AIM and Media Release
19 February 2021
BASE RESOURCES
LIMITED
Updated Kwale North Dune and Maiden Bumamani Mineral Resources
Estimates
Key Points
- As part of the pre-feasibility study currently underway to
assess the viability of mining the Kwale North Dune and Bumamani
deposits, seeking to extend the mine life of Kwale Operations,
additional drilling and mineralogy assessments have been
conducted.
- The Kwale North Dune Mineral Resources estimate has increased
by 13% to 194 million tonnes at an average HM grade of 1.5%,
containing 2.9Mt HM, based on a 1% HM cut-off grade.
- 99% of the Kwale North Dune Mineral Resources estimate is now
reported in the Measured and Indicated categories.
- The maiden Bumamani Mineral Resources estimate is 5.9 million
tonnes at an average HM grade of 1.9%, containing 0.115Mt HM, based on a 1% HM cut-off grade.
- The pre-feasibility study for the Kwale North Dune and Bumamani
deposits is due for completion early in Q2 2021.
African mineral sands producer, Base Resources Limited
(ASX / AIM: BSE) (Base Resources) is pleased to provide an
update to the Kwale North Dune Mineral Resources (2021
Kwale North Dune Mineral Resources) estimate and announce a
maiden Bumamani Mineral Resources estimate (2021
Bumamani Mineral Resources) at its 100% owned and
operated mineral sands operations in Kwale County, Kenya (Kwale Operations).
The 2021 Kwale North Dune Mineral Resources and 2021 Bumamani
Mineral Resources estimates are being presented together because of
the close proximity of the underlying deposits and as these
deposits are the subject of a single pre-feasibility study (the
Kwale North Dune PFS) being undertaken to assess their
potential to extend the mine life of Kwale Operations. The
Kwale North Dune PFS commenced in early 2020 and is due for
completion early in the second quarter of 2021.
Since announcement of the maiden JORC 2012 North Dune Mineral
Resources estimate in May 2019
(2019 Kwale North Dune Mineral
Resources)1, Base Resources has carried out
additional drilling, assaying and mineralogy studies of the Kwale
North Dune to improve the confidence of the Mineral Resources
estimate and further the Company’s understanding of the deposit.
As a result of this additional work, 99% of the 2021 Kwale
North Dune Mineral Resources estimate is now reported in the
Measured and Indicated categories. Material tonnage for the
2021 Kwale North Dune Mineral Resources estimate has also increased
by 13% and contained heavy mineral (HM) has increased by 12%
from the 2019 Kwale North Dune Mineral Resources estimate.
The 2021 Kwale North Dune Mineral Resources are now estimated to
be 194 million tonnes (Mt) at an average HM grade of 1.5%
for 2.9Mt of contained HM, at a 1% HM cut-off grade.
The Bumamani deposit is situated approximately 1.5km south of
the North Dune deposit (Figure 1) and was discovered by Base
Resources in 2017 when drilling to test for mineralisation in the
north-east sector of the Kwale Prospecting Licence PL/2018/0119
(PL119). At that time, taking into account the results
at hand and the small size of the deposit indicated by such
results, it was decided that any Mineral Resources estimate would
be deferred until the full drilling program planned for the
north-east sector was able to be completed and the full results
incorporated into the estimation process. Due to ongoing
community access issues, Base Resources has not been able to
complete that program. However, with commencement of the
Kwale North Dune PFS, the Bumamani deposit has now been revisited
due to its proximity to the Kwale North deposit and a Mineral
Resources estimate completed to allow its inclusion in that
study.
The maiden 2021 Bumamani Mineral Resources estimate was
developed from 2,977.5m of drilling
from 183 holes and is 5.9Mt at an average HM grade of 1.9% for
0.115Mt of contained HM, at a 1% HM
cut-off grade.
The 2021 Kwale North Dune Mineral Resources and the 2021
Bumamani Mineral Resources estimates are reported in accordance
with the JORC Code. Base Resources has a net attributable
interest of 100% in the 2021 Kwale North Dune Mineral Resources and
the 2021 Bumamani Mineral Resources.
The information prescribed by the ASX Listing Rules, including a
summary of the information material to understanding each Mineral
Resources estimate in respect of the prescribed matters, is set out
in the sections below. For each Mineral Resources estimate,
such information should be read in conjunction with the explanatory
information provided in respect of the applicable estimate for the
purposes of Sections 1 to 3 of Table 1 of the JORC Code - see
Appendix 1 to this announcement in the case of the 2021 Kwale
North Dune Mineral Resources estimate and Appendix 2 in the case of
the 2021 Bumamani Mineral Resources estimate.
Figures (graphics) referenced in this announcement have been
omitted. A full PDF version of this announcement, including
all figures (graphics), is available from Base Resources’
website: https://baseresources.com.au/investors/
announcements/.
[Note (1): Refer to Base
Resources’ market announcement “Mineral Resource for Kwale North
Dune deposit” released on 1 May 2019,
which is available at
https://baseresources.com.au/investors/announcements/]
Table 1: 2021 Kwale North Dune Mineral Resources estimate
compared with the 2019 Kwale North Dune Mineral Resources
estimate.
|
2021
as at 19 February 2021 |
2019
as at 1 May 2019 |
Category |
Tonnes
(Mt) |
HM
(Mt) |
HM
(%) |
SL
(%) |
OS
(%) |
HM Assemblage |
Tonnes
(Mt) |
HM
(Mt) |
HM
(%) |
SL
(%) |
OS
(%) |
HM Assemblage |
ILM
(%) |
RUT
(%) |
ZIR
(%) |
ILM
(%) |
RUT
(%) |
ZIR
(%) |
Kwale North Dune
Mineral Resources |
Measured |
119 |
1.8 |
1.5 |
37 |
1 |
42 |
13 |
6 |
- |
- |
- |
- |
- |
- |
- |
- |
Indicated |
73 |
1.0 |
1.4 |
37 |
2 |
50 |
14 |
6 |
136 |
2.1 |
1.5 |
38 |
2 |
45 |
12 |
5 |
Inferred |
2 |
0.0 |
1.2 |
37 |
3 |
50 |
15 |
7 |
34 |
0.5 |
1.4 |
36 |
3 |
46 |
13 |
6 |
Total |
194 |
2.9 |
1.5 |
37 |
2 |
45 |
13 |
6 |
171 |
2.6 |
1.5 |
38 |
2 |
45 |
12 |
5 |
Table subject to rounding differences, resources
estimated at a 1% HM cut-off grade.
Table 2: Maiden 2021 Bumamani Mineral Resources
estimate.
|
2021
as at 19 February 2021 |
|
Category |
Tonnes
(Mt) |
HM
(kt) |
HM
(%) |
SL
(%) |
OS
(%) |
HM Assemblage |
Tonnes
(Mt) |
HM
(Mt) |
HM
(%) |
SL
(%) |
OS
(%) |
HM Assemblage |
ILM
(%) |
RUT
(%) |
ZIR
(%) |
ILM
(%) |
RUT
(%) |
ZIR
(%) |
Bumamani Mineral
Resources |
Measured |
3.0 |
66 |
2.2 |
19 |
2 |
48 |
15 |
7.5 |
N/A |
Indicated |
2.6 |
45 |
1.7 |
23 |
5 |
47 |
16 |
7.7 |
Inferred |
0.3 |
4 |
1.4 |
27 |
6 |
41 |
14 |
7.8 |
Total |
5.9 |
115 |
1.9 |
21 |
4 |
47 |
15 |
7.6 |
Table subject to rounding differences, resources
estimated at a 1% HM cut-off grade.
Further information relevant to
both Mineral Resources estimates
Kwale Operations is located on Special Mining Lease 23
(SML 23), which lies within PL119. The
Prospecting Licence covers an area of 88.7km2, which
includes the Kwale North and Bumamani deposits, and is located
approximately 50 kilometres south of Mombasa and approximately 10
kilometres inland from the Kenyan coast (Figure 1).
The Kwale Project initially comprised three areas that contained
concentrations of heavy minerals. They were the South Dune,
Central Dune (now totally depleted by mining and currently the
repository for sand tailings from the South Dune) and the North
Dune deposits (Figure 2), with the Bumamani deposit only being
discovered in 2017 after mining operations had commenced.
The project was initially owned by Tiomin Resources Inc.
(Tiomin) which conducted drilling in 1997 and then by Base
Titanium Limited (a wholly owned subsidiary of Base Resources)
which purchased the project late in 2010 and commenced confirmatory
drilling of the Central, South and North Dune deposits. The
North Dune deposit was initially excluded from the project’s
Mineral Resources on the basis of HM grade and the then prevailing
economic conditions. However, in 2018, it was decided to
re-evaluate the potential of the North Due in light of improved
economic conditions, refined resource definition methodology and
with insights gained from five years of operations on the Central
Dune. Following that decision, the 2019 Kwale North Dune
Mineral Resources estimate was announced.
The rocks of the area are of sedimentary origin and range in age
from Upper Carboniferous to Recent. Three divisions are
recognised: the Cainozoic rocks, the Upper Mesozoic rocks (not
exposed within the area) and the Duruma Sandstone Series giving
rise to the dominant topographical feature of the area: the Shimba
Hills. The Shimba grits and Mazeras sandstone are of Upper
Triassic age and form the Upper Duruma Sandstone.
The Magarini sands form a belt of low hills running parallel to
the coast. They rest with slight unconformity on the Shimba
grits and Mazeras sandstone. This formation was deposited
during Pliocene times and consists mainly of unconsolidated
fluviatile sediments derived from the Duruma Sandstone Series.
The Kwale deposits are an aeolian subset of the Magarini sands
and are generally poorly stratified and contain a fraction of clay,
which for the North Dune and Bumamani deposits is approximately 37%
and 21%, respectively. Heavy minerals, mainly ilmenite,
rutile and zircon, are locally concentrated and are abundant in
some places, giving rise to the deposits.
Further information specific to the
2021 Kwale North Dune Mineral Resources estimate
The geological interpretations for the Kwale North Dune deposit
considered the data in the drill logs, HM assay results,
microscopic logging of HM sinks, detailed mineralogy and knowledge
gained from mining the Central Dune and South Dune deposits.
Four geological domains have been identified at the Kwale North
Dune deposit. These were used and honoured during the
geological modelling (Figure 3).
The uppermost zone at the Kwale North Dune deposit, referred to
as Ore Zone 1, is a dark brown, predominantly fine grained, well
sorted silty sand with very little induration and is similar to the
Ore Zone 1 units in the other Kwale deposits.
Mineralogically, it is characterised by clean, glossy and rounded
HM grains with an average valuable heavy mineral (VHM)
content of approximately 75%.
Ore Zone 4 lies below Ore Zone 1, with an indurated
paleo-surface separating the two zones, as observed in the field
through difficult drill bit penetration, and in HM sink logs,
exhibiting elevated iron oxides. The Ore Zone 4 host is
higher in slimes with difficult washability and the grain sorting
is generally poor. It is slightly lower in VHM content (71%),
often with elevated iron oxides and alumino-silicate minerals
(kyanite, andalusite and sillimanite). Ore Zone 4 is
considered a fluvial deposit based on the difficulty of wash and
the poor grain sorting.
Ore Zone 5 lies below Ore Zone 4 and is separated from that zone
by a lateritic paleo-surface and is also hosted in a fluviatile
clay-rich, poorly sorted formation. It is distinguished
mineralogically by an increased amount of almandine garnet that
reports to the magnetic fraction, significantly increasing
magnesium, manganese, aluminium and silicon in the oxide
chemistry. As a result of this, Ore Zone 5 has a notably
lower average VHM content (44%).
The Basement Zone lies below Ore Zone 5 and is typically hosted
in weathered variants of the Mesozoic (Permo-Triassic) Duruma
Sandstones. It does contain mineralisation which was reported
in the 2019 Kwale North Dune Mineral Resources estimate as Ore Zone
10. However, it has a VHM content of just 10% being
predominantly titano-haematite (<40% TiO2) to which
no value is ascribed, with zircon enrichment in the non-magnetic
fraction. This mineralisation was assessed at scoping
level. It is not considered to hold potential for eventual
economic extraction due to its low VHM content, depth of burial,
high slime content (42%), high grade variability, presence of
induration and the fact that most of it lies below the water table
(significantly increasing the cost and complexity of mining) and is
therefore not reported.
For Ore Zones 1, 4 and 5, a strong correlation between the field
logs, HM sink logs and XRF oxide chemistry and QEMSCAN mineralogy
gives confidence to these interpretations.
Following acquisition of the Kwale Project, subsequent resource
drilling by Base Resources’ wholly-owned subsidiary, Base Titanium
Limited, of the Kwale North deposit was completed using the reverse
circulation, air core (RCAC) method and conducted in three
campaigns: November 2010,
December 2012 to April 2013 and June
2018 to May 2019 (Figure
4). A total of 745 holes were drilled for 27,429 metres and
generated 15,441 samples for assay. Tiomin drilled 37 holes
in 1997 but, due to poor twinned hole assay repeatability at other
areas of the Kwale Project, no Tiomin drilling information was used
by Base Resources for the 2019 Kwale North Dune Mineral Resources
estimate and this is also the case of the 2021 Kwale North
Dune Mineral Resources.
The predominantly three metre sample intervals in the 2010 and
2012/13 drilling were replaced by sampling at 1.5 metre intervals
for the 2018/19 drill program to provide greater control on
geological boundaries. Sample sizes averaged close to 3kg at
this sample interval when collecting 25% of the rotary splitter
cycle. Samples were dried, weighed, and screened for material
less than 45 micrometres (slimes) and +1 mm (oversize).
Approximately 100 grams of the screened sample was subjected to
a HM float/sink technique using the heavy liquid, lithium
polytungstate (LST) with a specific gravity of 2.85 grams per cubic
centimetre. The resulting HM concentrate was dried and
weighed as were the other separated constituent size fractions (the
minus 45 micrometre material being calculated by difference).
Mineral assemblage analyses were conducted by Base Resources to
characterise the mineralogical and chemical characteristics of
specific mineral species and magnetic fractions. These
mineral assemblage samples were subjected to magnetic separation
using a Mineral Technologies induced-roll magnetic separator which
captures magnetic (mag), middling (mid) and
non-magnetic (non-mag) fractions. The mid and mag
fractions were combined and, with the non-mag fraction, were
subjected to XRF analysis using a Bruker, S8 Tiger XRF.
Data from the mag and non-mag XRF analyses are processed through
an algorithm (Minmod) that runs approximately 100,000
iterations in assigning key chemical species to derive a calculated
mineralogy determination.
Drill hole collar and geology data was captured by
industry-specific, field logging software with on-board
validation. Field and assay data were managed in a MS Access
database and subsequently migrated to a more secure SQL
database.
Standard samples were generated and certified for use in the
field and laboratory. Accuracy of HM and slimes (SL)
analysis was verified by using the standard samples and monitored
using control charts. Standard errors greater than three
standard deviations from the mean prompted batch re-assay. A
standard precision analysis was conducted on the key assay fields:
HM, SL and Oversize (OS) for both laboratory and field
duplicate samples. Normal scatter and QQ plots were prepared
for HM, SL and OS for laboratory and field duplicates.
A twin drilling program was introduced for the 2018 program to
quantify short-range variability in geological character and grade
intersections. A water injection versus dry drilling
assessment was included in the twin drilling analysis. Field
and laboratory duplicate, standard and twin drilling analysis show
adequate level of accuracy and precision to support resource
classifications as stated.
A topographic DTM was prepared by Base Resources based on a
LIDAR survey.
Construction of the geological grade model was based on coding
model cells below open wireframe surfaces, comprising topography,
geology (Ore Zones 1, 4, and 5) and basement (Figure 3).
Model cell dimensions of 50m x
50m x 1.5m in the XYZ orientations were utilised.
Interpolation was undertaken using various sized search ellipses
to populate the model with primary grade fields (HM, SL and OS),
and index fields (hardness, induration percent, mineralogy).
Inverse distance weighting to a power of three was used for primary
assay fields whilst nearest neighbour was used to interpolate index
fields. Figure 5 shows an oblique view of the model coloured
by HM grades.
A fixed bulk density of 1.7 (t/m3) was applied to the
2021 Kwale North Dune Mineral Resources model. This bulk
density was selected based on operational experience in the Kwale
Central and South Dune deposits and because no bulk density
sampling was undertaken. This is considered to be a
conservative estimate of bulk density.
The Kwale North Dune deposit, being similar in nature to the
Kwale South Dune deposit currently being mined, is considered
amenable to being mined and processed in the same way. That
is, by using the existing plant and equipment at the Kwale
Operations: hydraulic mining, spiral concentrator and mineral
separation plant with magnetic, electrostatic and further gravity
separation. The only departure from current methodology is
that, for the Kwale North Dune deposit, the fine and coarse
tailings are likely to be co-disposed together. Apart from
that, there is no indication that the mining, metallurgical and
operating cost modifying factors for the Kwale North deposit would
be materially different to those derived from mining the Kwale
South Dune deposit.
The criteria used for classification was primarily the drill
spacing (predominantly 100m x
100m) and sample interval
(predominantly 1.5m), with
consideration also given to the continuity of mineral assemblage
information. The ore zones exhibit spatially different
classifications mainly because of differing density of
mineralogical information and variography. The reason for the
increased material tonnes between the 2019 and 2021 Kwale North
Dune Mineral Resources estimates is that the area covered by assays
has increased. The reason for the increased confidence levels
in the 2021 Kwale North Dune Mineral Resources estimate is refined
variography assessments for Ore Zones 1 and 5 which indicate
increased ranges in the primary and/or secondary directions of
grade continuity compared to the 2019 Kwale North Dune Mineral
Resources. The 2021 Kwale North Dune Mineral
Resources estimate used a 1% HM bottom cut because the
economic cut-off grade at the nearby Kwale South Dune deposit mine
is near to this, and resource estimates for Kwale Operations have
historically been reported at this cut-off grade. Figures 4,
6 and 7 show the distribution of the resource classifications for
Ore Zones 1, 4 and 5, respectively.
Further information specific to the
2021 Bumamani Mineral Resources estimate
The geological interpretations for the Bumamani deposit
considered the data in the drill logs, HM assay results,
microscopic logging of HM sinks, detailed mineralogy and knowledge
gained from mining the Central Dune and South Dune deposits.
Three geological domains have been identified at the Bumamani
deposit. These were used and honoured during the geological
modelling (Figure 8).
The uppermost zone at the Bumamani deposit, referred to as Ore
Zone 1 (Figure 9), is a dark brown, predominantly fine grained,
well sorted silty sand with very little induration and is similar
to the Ore Zone 1 units in the other Kwale deposits. It
averages 1.9% HM, 21% SL and 4% OS. The zone gets sandier to
the east with reduced silt content. Mineralogically it is
characterised by clean, glossy and rounded HM grains with an
average VHM content of approximately 70% VHM.
Ore Zone 4 (Figure 10) lies below Ore Zone 1, with the two zones
separated by a lateritic paleo-surface which may imply a time-gap
in depositional history. Ore Zone 4 is a fluviatile unit
represented locally with poorly sorted sandy clays and gritty
sands. The Ore Zone 4 domain averages 1.8% HM, 23.6% SL and
6.4% OS. Ore Zone 4 is mineralogically similar to Ore Zone
1.
The Basement Zone at the Bumamani deposit lies beneath Ore Zone
4 and comprises compacted clays, sandy-clays, limestone and fluvial
sands. The grain sizes range from silt to pebbles and
boulders, with generally poor sorting and is characterised by trace
concentrations of HM typically with low VHM content.
For Ore Zones 1 and 4, a strong correlation between the field
logs, HM sink logs and XRF oxide chemistry and QEMSCAN mineralogy
gives confidence to these interpretations.
Drilling by Base Resources’ wholly-owned subsidiary, Base
Titanium Limited, of the Bumamani deposit was completed using the
RCAC method and conducted in two campaigns in 2017 and 2018, both
employing 76mm diameter, 3m long NQ
drill rods. A total of 183 holes were drilled for
2,977.5m at 1.5m sampling intervals and generated 1,968
assayed samples. Holes were drilled 50m apart on lines 100m apart. Samples were split using a rig
mounted rotary splitter which delivered an average of 2.7kg of dry
sample per interval. Samples were dried, weighed, and
screened for material less than 45 micrometres (slimes) and +1mm
(oversize).
Approximately 100 grams of the screened sample was subjected to
a HM float/sink technique using the heavy liquid, lithium
polytungstate (LST) with a specific gravity of 2.85 grams per cubic
centimetre. The resulting HM concentrate was dried and
weighed as were the other separated constituent size fractions (the
minus 45 micrometre material being calculated by difference).
Mineral assemblage analyses were conducted by Base Resources to
characterise the mineralogical and chemical characteristics of
specific mineral species and magnetic fractions. These
mineral assemblage samples were subjected to magnetic separation
using a Mineral Technologies induced-roll magnetic separator which
captures mag, mid and non-mag fractions. The mid and mag
fractions were combined and, with the non-mag fraction, were
subjected to XRF analysis using a Bruker, S8 Tiger XRF.
Data from the mag and non-mag XRF analyses was processed through
the Minmod algorithm that runs approximately 100,000 iterations in
assigning key chemical species to derive a calculated mineralogy
determination.
Drill hole collar and geology data was captured by
industry-specific, field logging software with on-board
validation. Field and assay data were managed in a MS Access
database and subsequently migrated to a more secure SQL
database.
Standard samples were generated and certified for use in the
field and laboratory. Accuracy of HM and SL analysis was
verified by using the standard samples and monitored using control
charts. Standard errors greater than three standard
deviations from the mean prompted batch re-assay. A standard
precision analysis was conducted on the key assay fields: HM, SL
and OS for both laboratory and field duplicate samples.
Normal scatter and QQ plots were prepared for HM, SL and OS for
laboratory and field duplicates.
A twin drilling program was introduced for the 2018 program to
quantify short-range variability in geological character and grade
intersections. A water injection versus dry drilling
assessment was included in the twin drilling analysis. Field
and laboratory duplicate, standard and twin drilling analysis show
adequate level of accuracy and precision to support resource
classifications as stated.
A topographic DTM was prepared by Base Resources based on a
LIDAR survey.
Construction of the geological grade model was based on coding
model cells below open wireframe surfaces, comprising topography,
geology (Ore Zones 1 and 4) and basement (Figure 8). Model
cell dimensions of 50m x 50m x 1.5m in the
XYZ orientations were utilised.
Interpolation was undertaken using various sized search ellipses
to populate the model with primary grade fields (HM, SL and OS),
and index fields (hardness, induration percent, mineralogy).
Inverse distance weighting to a power of three was used for primary
assay fields whilst nearest neighbour was used to interpolate index
fields. Figure 11 shows an oblique view of the model coloured
by HM grade.
A fixed bulk density of 1.7 (t/m3) was applied to the
2021 Bumamani Mineral Resources estimate model. This bulk
density was selected based on operational experience in the Kwale
Central and South Dune deposits and because no bulk density
sampling was undertaken. This is considered to be a
conservative estimate of bulk density.
The Bumamani deposit, being similar in nature to the Kwale South
Dune deposit currently being mined, is considered amenable to being
mined and processed in the same way. That is, by using the
existing plant and equipment at the Kwale Operations: hydraulic
mining, spiral concentrator and mineral separation plant with
magnetic, electrostatic and further gravity separation. The
only departure from current methodology is that, for the Bumamani
deposit (like for the Kwale North Dune deposit), the fine and
coarse tailings are likely to be co-disposed together. Apart
from that, there is no indication that the mining, metallurgical
and operating cost modifying factors for the Bumamani deposit would
be materially different to those derived from mining the Kwale
South Dune deposit.
The criteria used for classification was primarily the drill
spacing (predominantly 100m x
50m) and sample interval
(1.5m), with consideration also given
to the continuity of mineral assemblage information. The ore
zones exhibit spatially different classifications mainly because of
differing density of mineralogical information. The
2021 Bumamani Mineral Resources estimate used a 1% HM bottom
cut because the economic cut-off grade at the nearby Kwale South
Dune deposit mine is near to this, and resource estimates for Kwale
Operations have historically been reported at this cut-off
grade. Figures 9 and 10 show the distribution of the resource
classifications for Ore Zones 1 and 4 respectively.
Competent Persons'
Statements
2021 Kwale North Dune Mineral
Resources estimate
The information in this announcement that relates to the 2021
Kwale North Dune Mineral Resources estimate is based on, and fairly
represents, information and supporting documentation prepared by
Mr. Greg Jones, who acts as a Consultant Geologist for Base
Resources and is employed by IHC Robbins. Mr. Jones is a
Fellow of The Australasian Institute of Mining and Metallurgy and
has sufficient experience that is relevant to the style of
mineralisation, type of deposits under consideration and activity
which he is undertaking to qualify as a Competent Person as defined
in the JORC Code and as a Qualified Person for the purposes of the
AIM Rules for Companies. Mr. Jones has reviewed this
announcement and consents to the inclusion in this announcement of
the 2021 Kwale North Dune Mineral Resources estimate and supporting
information in the form and context in which that information
appears.
2021 Bumamani Mineral Resources
estimate
The information in this announcement that relates to the 2021
Bumamani Mineral Resources estimate is based on, and fairly
represents, information and supporting documentation prepared by
Mr. Scott Carruthers. Mr.
Carruthers is a Member of The Australasian Institute of Mining and
Metallurgy. Mr. Carruthers is employed by Base Resources,
holds equity securities in Base Resources, and is entitled to
participate in Base Resources’ long-term incentive plan and receive
equity securities under that plan. Details about that plan
are included in Base Resources’ 2020 Annual Report. Mr.
Carruthers has sufficient experience that is relevant to the style
of mineralisation, type of deposits under consideration and
activity which he is undertaking to qualify as a Competent Person
as defined in the JORC Code and as a Qualified Person for the
purposes of the AIM Rules for Companies. Mr. Carruthers has
reviewed this announcement and consents to the inclusion in this
announcement of the 2021 Bumamani Mineral Resources estimate and
supporting information in the form and context in which that
information appears.
Forward Looking Statements
Certain statements in or in connection with this announcement
contain or comprise forward looking statements.
By their nature, forward looking statements involve risk and
uncertainty because they relate to events and depend on
circumstances that will occur in the future and may be outside Base
Resources’ control. Accordingly, results could differ
materially from those set out in the forward-looking statements as
a result of, among other factors, changes in economic and market
conditions, success of business and operating initiatives, changes
in the regulatory environment and other government actions,
fluctuations in product prices and exchange rates and business and
operational risk management. Subject to any continuing
obligations under applicable law or relevant stock exchange listing
rules, Base Resources undertakes no obligation to update publicly
or release any revisions to these forward-looking statements to
reflect events or circumstances after the date of this announcement
or to reflect the occurrence of unanticipated events.
No representation or warranty, express or implied, is made as to
the fairness, accuracy or completeness of the information contained
in this announcement (or any associated presentation, information
or matters). To the maximum extent permitted by law, Base
Resources and its related bodies corporate and affiliates, and
their respective directors, officers, employees, agents and
advisers, disclaim any liability (including, without limitation,
any liability arising from fault, negligence or negligent
misstatement) for any direct or indirect loss or damage arising
from any use or reliance on this announcement or its contents,
including any error or omission from, or otherwise in connection
with, it.
Nothing in this announcement constitutes investment, legal or
other advice. You must not act on the basis of any matter
contained in this announcement but must make your own independent
investigation and assessment of Base Resources and obtain any
professional advice you require before making any investment
decision based on your investment objectives and financial
circumstances. This announcement does not constitute an
offer, invitation, solicitation, advice or recommendation with
respect to the issue, purchase or sale of any security in any
jurisdiction.
Appendix 1 – 2021 Kwale North Dune
Mineral Resources estimate
JORC Code, 2012 Edition
Section 1 Sampling Techniques and
Data
(Criteria in this section apply to all succeeding sections.)
Criteria |
Explanation |
Comment |
Sampling techniques |
Nature and quality of sampling (e.g., cut channels, random
chips, or specific specialised industry standard measurement tools
appropriate to the minerals under investigation, such as down hole
gamma sondes, or handheld XRF instruments, etc). These examples
should not be taken as limiting the broad meaning of
sampling.
Include reference to measures taken to ensure sample
representivity and the appropriate calibration of any measurement
tools or systems used.
Aspects of the determination of mineralisation that are Material
to the Public Report. In cases where ‘industry standard’ work has
been done this would be relatively simple (e.g., ‘reverse
circulation drilling was used to obtain 1 m samples from which 3 kg
was pulverised to produce a 30 g charge for fire assay’). In other
cases, more explanation may be required, such as where there is
coarse gold that has inherent sampling problems. Unusual
commodities or mineralisation types (e.g., submarine nodules) may
warrant disclosure of detailed information. |
Reverse
circulation aircore drilling was used to collect downhole samples
for the project.
Of the 745 drill holes used for this resource update, 21 of them
(drilled between 2010 – mid 2012) utilised 3m sample intervals.
The remaining 724 drill holes used 1.5m sample intervals from
mid-2012 to 2019 using an on-board rotary splitter mounted beneath
the rig cyclone.
Sample gates were set to collect 25% of the splitter cycle, which
delivered about 2.5 - 3.5kg of sample per interval on average.
Duplicate samples were collected at the splitter for every 20th
sample simultaneously with the original sample.
A representative grab sample from the sample bags was routinely
washed and panned for a visual HM content estimate. |
Drilling techniques |
Drill
type (e.g., core, reverse circulation, open-hole hammer, rotary air
blast, auger, Bangka, sonic, etc) and details (e.g., core diameter,
triple or standard tube, depth of diamond tails, face-sampling bit
or other type, whether core is oriented and if so, by what method,
etc). |
122 holes
in the 2010, 2012/2013 campaigns were drilled with a RCAC Wallis
Mantis 75 drill rig using NQ drill tooling of about 76mm in
diameter.
567 holes in the 2018 campaign and the 56 holes in the 2019
campaign were drilled with a more modernised Mantis 80 drill rig,
also using NQ drill bits.
For the 2010 and 2012/13 campaigns, the mast was oriented
vertically (90º) by sight. For the 2018/19 drilling campaign,
the rig mast was orientated vertically by spirit level prior to
drilling to adhere to best practice for geological boundary
delineation.
Drilling was recorded in geological logs as either dry or water
injected, depending on ground conditions. Water injection was
employed to assist with penetration through clays/rock and maintain
sample quality and delivery. |
Drill
sample recovery |
Method of recording and assessing core and chip sample
recoveries and results assessed.
Measures taken to maximise sample recovery and ensure
representative nature of the samples.
Whether a relationship exists between sample recovery and grade
and whether sample bias may have occurred due to preferential
loss/gain of fine/coarse material. |
Sample
condition was logged at the rig as either good, moderate or poor,
with good meaning not contaminated and appropriate sample size
(recovery), moderate meaning not contaminated, but sample over or
under sized, and poor meaning contaminated or grossly
over/undersized.
Slightly damp ground conditions with approximately 36% silt/clay
meant that best sample quality was found to be achieved via slow
penetration with water injection to aid in the sample recovery.
No relationship is believed to exist between grade and sample
recovery. No bias is also believed to occur due to loss of fine
material. |
Logging |
Whether core and chip samples have been geologically and
geotechnically logged to a level of detail to support appropriate
Mineral Resource estimation, mining studies and metallurgical
studies.
Whether logging is qualitative or quantitative in nature. Core
(or costean, channel, etc) photography.
The total length and percentage of the relevant intersections
logged. |
Field
logging was recorded for all 16,257 fixed, down-hole intervals and
was conducted as drilling and sampling proceeded. Logging was based
on a representative grab sample that was panned for heavy mineral
estimation and host material observations.
Logging codes were designed to capture observations on lithology,
colour, grainsize, induration and estimated mineralisation. Any
relevant comments e.g., water table, gangue HM components and
stratigraphic markers were included to aid in the subsequent
geological modelling.
A qualitative estimate of how representative a sample was of the
drilled interval was recorded by Base Titanium Limited (BTL)
field geologists whilst logging. This sample condition field
records whether the hole was drilled with injected water or dry and
sample size (and the influence of contamination or sample loss)
directs the quality assessment of each sample.
Heavy mineral sinks from assayed samples were logged routinely
under a reflected-light, stereoscopic microscope. This work
was carried out to capture information relating to VHM content,
mineralogy, HM grainsize and quality. |
Sub-sampling techniques and sample preparation |
If
core, whether cut or sawn and whether quarter, half or all core
taken.
If non-core, whether riffled, tube sampled, rotary split, etc
and whether sampled wet or dry.
For all sample types, the nature, quality and appropriateness of
the sample preparation technique.
Quality control procedures adopted for all sub-sampling stages
to maximise representivity of samples.
Measures taken to ensure that the sampling is representative of
the in-situ material collected, including for instance results for
field duplicate/second-half sampling.
Whether sample sizes are appropriate to the grain size of the
material being sampled. |
Rotary
split at the sampling cyclone on the rig. Approximately 25%
of the original sample retained. Duplicate samples were collected
at every 20th sample. The drill rods and cyclone were routinely
cleaned between holes using pressurised water to avoid inter-hole
contamination. The sample size is considered appropriate for
the grain size of the material because the grade of HM is measured
in per cent, and a 2.5-5kg sample contains in excess of 50 million
grains of sand.
The sample preparation flow sheet departed from standard mineral
sand practices in one respect; the samples were not oven dried
prior to de-sliming, to prevent clay minerals being baked onto the
HM grains (because the HM fractions were to be used in further
mineralogical test work). Instead, a separate sample was
split and dried to determine moisture content, which was accounted
for mathematically.
Pre-soaking of the sample Sodium (Tetra) Pyrophosphate
(TSPP) dispersant solution ensured a more efficient
de-sliming process and to avoid potentially under-reporting slimes
content. |
Quality of assay data and laboratory tests |
The
nature, quality and appropriateness of the assaying and laboratory
procedures used and whether the technique is considered partial or
total.
For geophysical tools, spectrometers, handheld XRF instruments,
etc, the parameters used in determining the analysis including
instrument make and model, reading times, calibrations factors
applied and their derivation, etc.
Nature of quality control procedures adopted (e.g., standards,
blanks, duplicates, external laboratory checks) and whether
acceptable levels of accuracy (i.e., lack of bias) and precision
have been established. |
The
assay process employed included a Sample Preparation stage,
completed by BTL staff, followed by a heavy liquid separation
(using lithium polytungstate: SG = 2.85g/cm3), completed
at Kwale Operations’ site laboratory.
Improvements to the sample preparation stage were made to ensure
industry best practice and to deliver a high degree of confidence
in the results. These included the following:
- A formalised process flow was generated, posted in all sample
preparation areas and used to train and monitor sample preparation
staff
- Regular monitoring was completed by BTL senior staff
- Field samples were left in their bags for initial air-drying to
avoid sample loss
- TSPP was introduced to decrease attrition time and improve
slimes recovery.A range of attrition times (with 5% TSPP) were
trialled and plotted against slimes recovery figures to determine
optimum attrition time (15 minutes)
- Staff were trained to use paint brushes and water spray rather
than manipulate sample through slimes screen by hand to remove the
potential for screen damage
- A calibration schedule was introduced for scales used in the
sample preparation stage
- The introduction of ruggedized computers allowed the capture of
sample preparation data digitally at inception.This greatly reduced
the instance of scribe and data entry errors
- Slimes screen number recorded to isolate batches should
re-assay be required due to poor adherence to procedure or to
identify screen damage
- Various quality control samples were submitted routinely to
assure assay quality. A total of 809 duplicate field samples,
809 lab duplicate sample preparation samples, 279 field certified
standard samples, and an unspecified number of internal laboratory
standards, repeats and blanks have been assayed at Kwale
Operations’ site laboratory.
|
Verification of sampling and assaying |
The
verification of significant intersections by either independent or
alternative company personnel.
The use of twinned holes.
Documentation of primary data, data entry procedures, data
verification, data storage (physical and electronic)
protocols.
Discuss any adjustment to assay data. |
The Kwale
North Dune deposit is a moderate to low HM grade, dunal-style
accumulation that does not carry excessive mineralisation or suffer
from ‘nugget’ effects, typical of other commodities.
No external audit validation was completed for the HM analyses
included in the 2021 Kwale North Dune Mineral Resources
estimate. This is not considered material given the adequate
performance of results from extensive QA/QC verification and on
account of low HM grade variance and deposit homogeneity.
A twin drill hole procedure was introduced for the 2018/19 program
at a recommended rate of 5% of the total number of holes.
These twins were used to quantify short-range variability in
geological character and grade intersections and ideally should be
placed throughout the deposit.
A total of 41 twin drill holes were completed during the 2018/19
Kwale North Dune drilling program, which represents about 5.7% of
the total program.
The spatially well-represented twin hole paired data shows very
good correlation considered material to the integrity/quality of
the resource data. |
Location of data points |
Accuracy and quality of surveys used to locate drill holes
(collar and down-hole surveys), trenches, mine workings and other
locations used in Mineral Resource estimation.
Specification of the grid system used.
Quality and adequacy of topographic control. |
Proposed
drill holes were sited on the ground using hand-held GPS.
After drilling, surveyors recorded collar positions via DGPS RTK
unit registered to local base stations. The accuracy of the
DGPS unit is stated at 0.02m in the X, Y and Z axes.
The survey Geodetic datum utilised was UTM Arc 1960, used in E.
Africa. Arc 1960 references the Clark 1880 (RGS) ellipsoid and the
Greenwich prime meridian. All survey data used in the
2021 Kwale North Mineral Resources estimate dataset has undergone a
transformation to the local mine grid from the standard UTM Zone
37S (Arc 1960). The local Grid was rotated 42.5o, which
aligns the average strike of the deposit with local North and is
useful for both grade interpolation and mining reference during
production.
All drill collars were projected to the local LIDAR survey, digital
terrain model, captured over the resource area in 2018/19 at a 2x2m
grid spacing. This was performed prior to interpretation and
model construction to eliminate any elevation disparities for the
block model construction. |
Data
spacing and distribution |
Data
spacing for reporting of Exploration Results.
Whether the data spacing, and distribution is sufficient to
establish the degree of geological and grade continuity appropriate
for the Mineral Resource and Ore Reserve estimation procedure(s)
and classifications applied.
Whether sample compositing has been applied. |
The
drill data spacing for the 2018/19 Kwale North Resource drilling
was nominally 100m X, 100m Y and 1.5m Z. Variations from this
spacing resulted from terrain/traverse difficulties and ground
access.
A sample spacing of 3m, with occasional 1.5m intervals at
geological contacts, was employed in the 2012/2013 drilling
campaign by BTL.
A 3m, down-hole block size was applied to model construction and
for consistency in the interpolation processes.
This spacing and distribution is considered sufficient to establish
the degree of geological and mineralisation continuity appropriate
for the resource estimation procedures and classifications
applied.
No sample compositing has been applied for HM, slimes and oversize
in the interpolation processes. |
Orientation of data in relation to geological structure |
Whether the orientation of sampling achieves unbiased sampling
of possible structures and the extent to which this is known,
considering the deposit type.
If the relationship between the drilling orientation and the
orientation of key mineralised structures is considered to have
introduced a sampling bias, this should be assessed and reported if
material. |
With the
geological setting being a layered dunal/fluviatile sequence, the
orientation of the deposit mineralisation in general is
sub-horizontal. All drill holes were orientated vertically to
penetrate the sub-horizontal mineralisation orthogonally.
Hole centres were spaced nominally at 100m. This cross-profiles the
dune so that variation can be determined. Down hole intervals were
nominated as 1.5m. This provides adequate sampling resolution to
capture the distribution and variability of geology units and
mineralisation encountered vertically down hole.
The orientation of the drilling is considered appropriate for
testing the horizontal and vertical extent of mineralisation
without bias. |
Sample
security |
The
measures taken to ensure sample security. |
Sample
residues from the prep stage were transferred to pallets and stored
in a locked shed beside the warehouse at Kwale Operations.
Residues from the Kwale Operations site laboratory were placed in
labelled bags and stored in numbered boxes. Boxes were placed
into a locked container beside the laboratory.
Sample tables are housed on a secure, network-hosted SQL
database. Administration privileges are limited to two BTL
staff: Exploration Superintendent and the Business Applications
Administrator.
Data is backed up every 12 hours and stored in perpetuity on a
secure, site backup server. |
Audits
or reviews |
The
results of any audits or reviews of sampling techniques and
data. |
In-house
reviews were undertaken by the Base Resources’ Resources Manager,
Mr. Scott Carruthers who is a Competent Person under the JORC
Code. |
Section 2 Reporting of Exploration
Results
(Criteria listed in the preceding section also apply to this
section.)
Criteria |
Explanation |
Comment |
Mineral tenement and land tenure status |
Type,
reference name/number, location and ownership including agreements
or material issues with third parties such as joint
ventures, partnerships, overriding royalties, native title
interests, historical sites, wilderness or national park and
environmental settings.
The security of the tenure held at the time of reporting along
with any known impediments to obtaining a licence to operate in the
area. |
The
Kwale North Dune is situated on a Prospecting License (PL) 100%
owned by Base Titanium Limited – PL/2018/0119 located in Kwale
County, Kenya. Base Titanium Limited is a wholly owned
subsidiary of Australian and UK-listed resources company, Base
Resources Limited.
The 88.7 km2 Prospecting License was granted on the 26th
of May 2018 for a three-year term ending 25th May 2021.
The PL is in good standing with the Kenya Ministry of Petroleum
& Mining at the time of reporting, with all statutory reporting
and payments up to date.
Local landowners generally supportive of exploration activities
with over 90% of planned holes drilled.
The existing Special Mining Lease 23 lies within the Prospecting
license area and covers the Kwale Central Dune deposit and some of
the Kwale South Dune deposit but does not include the Kwale North
Dune deposit. The Kenya Mining Act 2016 includes provision for the
amendment of an existing SML and for the conversion of an existing
PL to SML. |
Exploration done by other parties |
Acknowledgment and appraisal of exploration by other
parties. |
In 1996,
Tiomin carried out reconnaissance surface and hand-auger
sampling.
Following the encouraging results obtained, mud-rotary drilling was
undertaken in 1997 and 37 holes for a total of 1,824m was achieved
for the North dune, at 3m sampling intervals.
Prior to acquisition of the Kwale Project by Base Resources, Tiomin
prepared and published a North Dune Mineral Resources estimate of
116 Mt @ 2.1% HM using a 0.5% HM cut-off grade.
The current resource model omits the Tiomin data. This followed a
twin drilling analysis of the Tiomin Mud Rotary holes with Base
Resources’ RCAC to determine relevance of historical data to the
Kwale South Dune Mineral Resources estimate in 2016. A total
of 18 twin-hole pairs from a geographically dispersed area within
the South Dune were included for analysis. A very poor
correlation in HM values between the two methods (R2 =
0.1522) resulted from the study. It is assumed that the poor
correlation would extend to the North Dune.
This is expected, given the open-hole method of drilling employed
by Tiomin and supports the decision to exclude Tiomin data from the
current interpolation. |
Geology |
Deposit type, geological setting and style of
mineralisation. |
The
North Dune is part of the extensive Kwale Dune systems comprising
of reddish, windblown Magarini sand formations that overlie a
sequence of mineralised clay-rich fluviatile units, which in turn
overlie a Mesozoic sandstone Base, known as the Mazeras
formation.
These three units are separated by lateritic paleo-surfaces which
signify a time-gap between the geological formations.
The Mazeras Sandstone, derived from the disintegration of the
Mozambique Belt metamorphic rocks, has likely provided the supply
of heavy minerals to the Magarini sand dunes and the fluviatile
formations.
Exploration of the Kenyan coastline is yet to be successful in
terms of mineralised paleo-strandlines related to fossil marine
terraces, as these are likely buried beneath recent barren fluvial
overburden or were just not developed owing to reduced energy
levels from a fringing coral reef that has acted as a barrier to
effective winnowing and reworking of HM deposits. |
Drill
hole Information |
A
summary of all information material to the understanding of the
exploration results including a tabulation of the following
information for all Material drill holes:
If the exclusion of this information is justified on the basis
that the information is not Material and this exclusion does not
detract from the understanding of the report, the Competent Person
should clearly explain why this is the case. |
Drilling
by year (max, min and average depths) used for the resource model
build are as follows:
- 2010
- 11 drill holes (depth: max 72m, min 24m, avg 56m).
- Total 582m drilled.
- 2012
- 31 drill holes (depth: max 75m, min 18m, avg 60m).
- Total 1,681.5m drilled.
- 2013
- 80 drill holes (depth: max 75m, min 27m, avg 55m).
- Total 3,792m drilled.
- 2018
- 567 drill holes (depth: max 117m, min 6m, avg 45 m).
- Total 20,477m drilled.
- 2019
- 56 drill holes (depth: max 30m, min 9m, avg 30m).
- Total 897m drilled.
See drill hole location plan, Figure 4.
All drill holes drilled vertically.
Exploration results are not being reported at this time. |
Data
aggregation methods |
In
reporting Exploration Results, weighting averaging techniques,
maximum and/or minimum grade truncations (e.g., cutting of high
grades) and cut-off grades are usually Material and should be
stated.
Where aggregate intercepts incorporate short lengths of
high-grade results and longer lengths of low-grade results, the
procedure used for such aggregation should be stated and some
typical examples of such aggregations should be shown in
detail.
The assumptions used for any reporting of metal equivalent
values should be clearly stated. |
Exploration results are not being reported at this time.
No equivalent values were used.
No aggregation of short length samples used as samples were
consistently 3m and 1.5m intervals. |
Relationship between mineralisation widths and intercept
lengths |
These
relationships are particularly important in the reporting of
Exploration Results.
If the geometry of the mineralisation with respect to the drill
hole angle is known, its nature should be reported.
If it is not known and only the down hole lengths are reported,
there should be a clear statement to this effect (e.g., ‘down hole
length, true width not known’). |
The
deposit sequences are sub-horizontal, and the vertically inclined
holes are a fair representation of true thickness. |
Diagrams |
Appropriate maps and sections (with scales) and tabulations of
intercepts should be included for any significant discovery being
reported These should include, but not be limited to a plan view of
drill hole collar locations and appropriate sectional
views. |
See
figures 3-7. |
Balanced reporting |
Where
comprehensive reporting of all Exploration Results is not
practicable, representative reporting of both low and high grades
and/or widths should be practiced to avoid misleading reporting of
Exploration Results. |
Exploration results are not being reported at this time. |
Other
substantive exploration data |
Other
exploration data, if meaningful and material, should be reported
including (but not limited to): geological observations;
geophysical survey results; geochemical survey results; bulk
samples – size and method of treatment; metallurgical test results;
bulk density, groundwater, geotechnical and rock characteristics;
potential deleterious or contaminating substances. |
The
proprietary Minmod mineralogy technique, developed and employed by
Base Resources, comprises an XRF analysis of the magnetic and
non-magnetic fractions of each composite or sample, the results
from which are then back-calculated to determine in-ground
mineralogy. Minmod represents an improvement on the previous
method (Geomod) that was not as effective at determining accessory
minerals in the Kwale assemblage. Minmod has been validated
by external quantitative analysis (QEMSCAN and SEM EDX) and is
considered sufficiently certified to support quoted resource
confidence in this report. |
Further
work |
The
nature and scale of planned further work (e.g., tests for lateral
extensions or depth extensions or large-scale step-out
drilling).
Diagrams clearly highlighting the areas of possible extensions,
including the main geological interpretations and future drilling
areas, provided this information is not commercially
sensitive. |
Additional 100 x 100m aircore drilling to in-fill gaps and extend
mineralisation in the open NW part of the deposit.
Recommended 50 x 50m aircore drilling across strike primarily to
improve across strike variography for Ore 4.
Generation of further Ore Zone 5 QEMSCAN composites for a more
confident mineralogical modelling.
Detailed tests to establish accurate bulk densities. |
Section 3 Estimation and Reporting of
Mineral Resources
(Criteria listed in section 1, and where relevant in section 2,
also apply to this section.)
Criteria |
Explanation |
Comment |
Database integrity |
Measures taken to ensure that data has not been corrupted by,
for example, transcription or keying errors, between its initial
collection and its use for Mineral Resource estimation
purposes.
Data validation procedures used. |
Field
data was captured in LogChief logging application and
automatically validated through reference to pre-set library table
configurations.
Typing or logging code errors, duplication of key identifiers
(e.g., HOLE_ID, SAMP_ID) and conflicts in related tables (e.g.,
down-hole depth) are quarantined by the software and require
resolving immediately before logging can proceed.
The SQL Database also has identical automated validation features.
Data import is unsuccessful until these data issues are
resolved.
Field logging and survey data from the SQL database were imported
into Datamine Discover (MapInfo) for sectional interpretation.
Validation steps included a visual interrogation of collar versus
geology depths, a review of hole locations against the drilling
plan and a check for missing or duplicated logged fields and
outliers. Any spurious or questionable entries were resolved
by the supervising Geologist.
At the completion of each hole, an entry was made to the
hand-written drilling diary. The diary recorded the hole name,
date, depth, number of samples, time of start and finish, a
description of the location of the hole in relation to the last
hole and other things. Such a diary provides valuable evidence if
there is an error in hole naming or surveying.
A geologist was employed to manage digital data capture at the
sample preparation laboratory to reduce the potential for data
entry error by unskilled labourers. A number of validation
checks were made of sample preparation data to ensure accurate data
entry and application of correct procedure by BTL staff. This
included:
- comparison of pre- versus post-oven weights
- comparison of split weight versus de-slimed weight
- comparison of split weight versus field sample weight
- all sample preparation data were sorted by each individual
field and outliers investigated
Assay results were delivered via email in 45 sample batches from
Kwale Operations’ site laboratory. These were in the form of CSV
text files and imported by batch number directly into the SQL
database tables where pre-set algorithms converted weights to
percentages and removed the moisture content. The calculated assay
results were then checked manually for missing records and out of
range or unrealistic values. |
Site
visits |
Comment on any site visits undertaken by the Competent Person
and the outcome of those visits.
If no site visits have been undertaken indicate why this is the
case. |
Base
Resources’ Resources Manager Scott Carruthers made one site visit
to review the SQL database and the geological interpretations. The
Competent Person is satisfied with the integrity of the database as
well as the delineation of the geological boundaries. |
Geological interpretation |
Confidence in (or conversely, the uncertainty of) the geological
interpretation of the mineral deposit.
Nature of the data used and of any assumptions made.
The effect, if any, of alternative interpretations on Mineral
Resource estimation.
The use of geology in guiding and controlling Mineral Resource
estimation.
The factors affecting continuity both of grade and
geology. |
The
geological interpretation was undertaken by the BTL Exploration
Superintendent using field logs and observations, assays, HM sachet
logs, XRF oxide chemistry and mineralogy data. The oversize grades
were particularly useful in determining the lateritic
paleo-surfaces between the geological zones.
The data spacing for the project is considered sufficient for grade
and mineralogical continuity.
Four mineralised geological zones and a basement zone were
identified and are used as constraints in the Mineral Resources
estimation.
The uppermost zone at Kwale North, referred to as Ore Zone 1, is a
dark brown, predominantly fine grained, well sorted silty sand with
very little induration. It is also characterised by a clean,
high value heavy mineral assemblage.
Ore Zone 4 lies below Ore Zone 1 with a clear lateritic boundary
observed in the field with slightly difficult bit penetration, and
in HM sink logs, exhibiting elevated iron oxides. Ore Zone 4
is lower in valuable heavy mineral content, often dominated by iron
oxides and Al2SiO4 polymorphs (kyanite,
andalusite and sillimanite). It is considered a fluvial deposit
based on the difficulty of wash and the poor grain sorting.
Ore Zone 5 lies below Ore Zone 4 and is separated from that zone by
a lateritic paleo-surface. It is unique mineralogically due
to an increased amount of almandine garnet that reports to the mag
fraction, significantly increasing the magnesium, manganese,
aluminium and silicon in the oxide chemistry, and this is also
reflected in QEMSCAN mineralogy.
For Ore Zones 1, 4 and 5, a strong correlation between the field
logs, HM sink logs and XRF oxide chemistry and QEMSCAN mineralogy
gives confidence to these interpretations.
The grade and mineralogy continuity is abruptly truncated at the
western edge by an interpreted normal fault that pushed basement
material to the surface with resultant low grades and trash
HM. |
Dimensions |
The
extent and variability of the Mineral Resource expressed as length
(along strike or otherwise), plan width, and depth below surface to
the upper and lower limits of the Mineral Resource. |
The 2021
Kwale North Dune Mineral Resources estimate is approximately 6,300m
along strike and about 1,200m across strike on average.
The average thickness of Ore 1, Ore 4 and Ore 5 are approximately
10m, 7m and 5m respectively. |
Estimation and modelling techniques |
The
nature and appropriateness of the estimation technique(s) applied
and key assumptions, including treatment of extreme grade values,
domaining, interpolation parameters and maximum distance of
extrapolation from data points. If a computer assisted estimation
method was chosen include a description of computer software and
parameters used.
The availability of check estimates, previous estimates and/or
mine production records and whether the Mineral Resource estimate
takes appropriate account of such data.
The assumptions made regarding recovery of by-products.
Estimation of deleterious elements or other non-grade variables
of economic significance (e.g., sulphur for acid mine drainage
characterisation).
In the case of block model interpolation, the block size in
relation to the average sample spacing and the search
employed.
Any assumptions behind modelling of selective mining
units.
Any assumptions about correlation between variables.
Description of how the geological interpretation was used to
control the resource estimates.
Discussion of basis for using or not using grade cutting or
capping.
The process of validation, the checking process used, the
comparison of model data to drill hole data, and use of
reconciliation data if available. |
The 2021
Kwale North Dune Mineral Resources estimation was undertaken using
Datamine Studio RM software.
Inverse Distance Weighting to the power of three was used to
interpolate assay grades (HM, Slimes, Oversize) from the drill hole
file.
Nearest Neighbour was used to interpolate the composite ID and
mineralogy data.
This is an update to the previous (and maiden JORC 2012) 2019 Kwale
North Dune Mineral Resources estimate, which was 171 Mt @ 1.5% HM
using a 1.0% cut-off grade. No mining has been undertaken.
No assumptions have been made as to the recovery of
by-products.
The parent cell size used in the grade interpolation (50m x 50m)
was half the average drill hole spacing on the X and Y axes, which
was 100m x 100m. The vertical thickness of the cell was the nominal
average drill sample interval i.e., 1.5m.
No assumptions were made behind modelling of selected mining
units.
No assumptions made about correlation behind variables.
Validation was undertaken by swathe plots, population distribution
analysis and visual inspection.
The geological zones were used to control the resource estimate by
constraining grade interpolations and reporting. |
Moisture |
Whether the tonnages are estimated on a dry basis or with
natural moisture, and the method of determination of the moisture
content. |
The
Mineral Resources estimate is on a dry tonnes basis. |
Cut-off
parameters |
The
basis of the adopted cut-off grade(s) or quality parameters
applied. |
The
economic cut-off of Kwale Operations is between 1% and 1.5% HM, and
historically Kwale Operations Mineral Resources estimate reporting
focuses on a 1% HM cut-off grade. |
Mining
factors or assumptions |
Assumptions made regarding possible mining methods, minimum
mining dimensions and internal (or, if applicable, external) mining
dilution. It is always necessary as part of the process of
determining reasonable prospects for eventual economic extraction
to consider potential mining methods, but the assumptions made
regarding mining methods and parameters when estimating Mineral
Resources may not always be rigorous. Where this is the case, this
should be reported with an explanation of the basis of the mining
assumptions made. |
It is
assumed that the hydraulic mining method used at the neighbouring
Kwale Operations would be used. The high slime content and
generally low levels of induration in the North Dune deposit
provide support for this mining method. This mining method is
being re-assessed as part of the Kwale North Dune PFS. |
Metallurgical factors or assumptions |
The
basis for assumptions or predictions regarding metallurgical
amenability. It is always necessary as part of the process of
determining reasonable prospects for eventual economic extraction
to consider potential metallurgical methods, but the assumptions
regarding metallurgical treatment processes and parameters made
when reporting Mineral Resources may not always be rigorous. Where
this is the case, this should be reported with an explanation of
the basis of the metallurgical assumptions made. |
The
existing concentrator, modified to accommodate the increased
slimes, and mineral separation plant at Kwale Operations are
assumed capable of processing the material with recoveries expected
to be aligned with present production. |
Environmental factors or assumptions |
Assumptions made regarding possible waste and process residue
disposal options. It is always necessary as part of the process of
determining reasonable prospects for eventual economic extraction
to consider the potential environmental impacts of the mining and
processing operation. While at this stage the determination of
potential environmental impacts, particularly for a greenfields
project, may not always be well advanced, the status of early
consideration of these potential environmental impacts should be
reported. Where these aspects have not been considered this should
be reported with an explanation of the environmental assumptions
made. |
Tailing
disposal is likely to utilise co-disposal of fine and coarse tails
together, initially into the Kwale Central pit void. Once
space is available, tailings would be co-disposed into the Kwale
North pit void. |
Bulk
density |
Whether assumed or determined. If assumed, the basis for the
assumptions. If determined, the method used, whether wet or dry,
the frequency of the measurements, the nature, size and
representativeness of the samples.
The bulk density for bulk material must have been measured by
methods that adequately account for void spaces (vugs, porosity,
etc), moisture and differences between rock and alteration zones
within the deposit.
Discuss assumptions for bulk density estimates used in the
evaluation process of the different materials. |
A fixed
dry bulk density of 1.7 (t/m3) was assumed for the Mineral Resource
estimation, based on operational experience of mining the Kwale
Central Dune and South Dune deposits. |
Classification |
The
basis for the classification of the Mineral Resources into varying
confidence categories.
Whether appropriate account has been taken of all relevant
factors (i.e., relative confidence in tonnage/grade estimations,
reliability of input data, confidence in continuity of geology and
metal values, quality, quantity and distribution of the
data).
Whether the result appropriately reflects the Competent Person’s
view of the deposit. |
The
Mineral Resource classification for the Kwale North deposit was
based on drill hole spacing, sample interval and the distribution
and influence of composite mineralogical samples.
The classification of the Measured, Indicated, and Inferred Mineral
Resources was supported by the uniform grid spacing of drilling,
uncomplicated and consistent geology, relatively good continuity of
mineralisation particularly along strike (and supported by the
domain controlled variography), confidence in the down hole
drilling data and supporting criteria as noted above.
As Competent Person, IHC Robbins Geological Services Manager, Greg
Jones, considers that the result appropriately reflects a
reasonable view of the deposit categorisation. |
Audits
or reviews. |
The
results of any audits or reviews of Mineral Resource
estimates. |
Peer
review was undertaken by Scott Carruthers, Base Resources’
Resources Manager, with focus on the process and output of the
geology interpretation, database integrity, whether wireframes
reflect the geological interpretation, and model vs. drill hole
grades. Mr. Carruthers was satisfied with these facets. |
Discussion of relative accuracy/ confidence |
Where
appropriate a statement of the relative accuracy and confidence
level in the Mineral Resource estimate using an approach or
procedure deemed appropriate by the Competent Person. For example,
the application of statistical or geostatistical procedures to
quantify the relative accuracy of the resource within stated
confidence limits, or, if such an approach is not deemed
appropriate, a qualitative discussion of the factors that could
affect the relative accuracy and confidence of the
estimate.
The statement should specify whether it relates to global or
local estimates, and, if local, state the relevant tonnages, which
should be relevant to technical and economic evaluation.
Documentation should include assumptions made and the procedures
used.
These statements of relative accuracy and confidence of the
estimate should be compared with production data, where
available. |
Variography was undertaken to determine the drill hole support of
the selected JORC classification.
Validation of the model vs drill hole grades by direct observation
and comparison of the results on screen.
The resource statement is a global estimate for the entire known
extent of the Kwale North deposit within the tenement area. |
Appendix 2 – 2021 Bumamani Mineral
Resources estimate
JORC Code, 2012 Edition
Section 1 Sampling Techniques and
Data
(Criteria in this section apply to all succeeding sections.)
Criteria |
JORC Code explanation |
Commentary |
Sampling techniques |
Nature and quality of sampling (e.g., cut channels, random
chips, or specific specialised industry standard measurement tools
appropriate to the minerals under investigation, such as down hole
gamma sondes, or handheld XRF instruments, etc). These examples
should not be taken as limiting the broad meaning of
sampling.
Include reference to measures taken to ensure sample
representivity and the appropriate calibration of any measurement
tools or systems used.
Aspects of the determination of mineralisation that are Material
to the Public Report.
In cases where ‘industry standard’ work has been done this would
be relatively simple (e.g., ‘reverse circulation drilling was used
to obtain 1 m samples from which 3 kg was pulverised to produce a
30 g charge for fire assay’). In other cases, more explanation may
be required, such as where there is coarse gold that has inherent
sampling problems. Unusual commodities or mineralisation types
(e.g., submarine nodules) may warrant disclosure of detailed
information. |
Reverse
circulation aircore drilling was used to collect downhole samples
for the project.
Sample sub-splits were collected at 1.5m down-hole intervals for
holes drilled, using an on-board rotary splitter mounted beneath
the rig cyclone.
Sample gates were set to collect approximately 25% of the splitter
cycle, which delivered about 2.7kg of sample per interval on
average.
Rig duplicate samples were collected at the splitter for every 20th
sample simultaneously with the original sample.
A representative grab sample from the sample bags was routinely
washed and panned for lithological logging and HM grade
estimate. |
Drilling techniques |
Drill
type (e.g., core, reverse circulation, open-hole hammer, rotary air
blast, auger, Bangka, sonic, etc) and details (e.g., core diameter,
triple or standard tube, depth of diamond tails, face-sampling bit
or other type, whether core is oriented and if so, by what method,
etc). |
40 holes
in the 2017 campaign were drilled with a RCAC Wallis Mantis 80
drill rig using NQ drill tooling of about 76mm in diameter and a
drilling capability of 100m.
143 holes in the 2018 campaign were similarly drilled with a Mantis
80 drill rig, also using NQ drill bits.
For both drilling campaigns, the rig mast was orientated vertically
by spirit level prior to drilling to adhere to best practice for
geological boundary delineation.
Drilling was recorded in geological logs as either dry or water
injected, depending on ground conditions. Water injection was
employed to assist with penetration through clays/rock and maintain
sample quality and delivery. |
Drill
sample recovery |
Method of recording and assessing core and chip sample
recoveries and results assessed.
Measures taken to maximise sample recovery and ensure
representative nature of the samples.
Whether a relationship exists between sample recovery and grade
and whether sample bias may have occurred due to preferential
loss/gain of fine/coarse material. |
Sample
condition was logged at the rig as either good, moderate or poor,
with good meaning not contaminated and appropriate sample size
(recovery), moderate meaning not contaminated, but sample over or
under sized and poor meaning contaminated or grossly
over/undersized.
Slightly damp ground conditions with approximately 20% silt/clay
meant that best sample quality was found to be achieved via slow
penetration with water injection to aid in the sample recovery.
No relationship is believed to exist between grade and sample
recovery. No bias is also believed to occur due to loss of fine
material. |
Logging |
Whether core and chip samples have been geologically and
geotechnically logged to a level of detail to support appropriate
Mineral Resource estimation, mining studies and metallurgical
studies.
Whether logging is qualitative or quantitative in nature. Core
(or costean, channel, etc) photography.
The total length and percentage of the relevant intersections
logged. |
Field
logging was recorded for all 1,968 fixed, down-hole intervals and
was conducted as drilling and sampling proceeded. Logging was based
on a representative grab sample that was panned for heavy mineral
estimation and host material observations.
Logging codes were designed to capture observations on lithology,
colour, grainsize, induration and estimated mineralisation. Any
relevant comments e.g., water table, gangue HM components and
stratigraphic markers were included to aid in the subsequent
geological modelling. |
Sub-sampling techniques and sample preparation |
If
core, whether cut or sawn and whether quarter, half or all core
taken.
If non-core, whether riffled, tube sampled, rotary split, etc
and whether sampled wet or dry.
For all sample types, the nature, quality and appropriateness of
the sample preparation technique.
Quality control procedures adopted for all sub-sampling stages
to maximise representivity of samples.
Measures taken to ensure that the sampling is representative of
the in-situ material collected, including for instance results for
field duplicate/second-half sampling.
Whether sample sizes are appropriate to the grain size of the
material being sampled. |
Rotary
split at the sampling cyclone on the rig. Approximately 25%
of the original sample retained. Duplicate samples were collected
at every 20th sample. The drill rods and cyclone were routinely
cleaned between holes using pressurised water to avoid inter-hole
contamination. The sample size is considered appropriate for
the grain size of the material because the grade of HM is measured
in per cent, and a 2.5-5kg sample contains in excess of 50 million
grains of sand.
The sample preparation process departed from standard mineral sand
practices in one respect; the samples were not oven dried prior to
de-sliming, to prevent clay minerals from baking onto the HM grains
(because the HM fractions were to be used in further mineralogical
test work). Instead, a separate sample was split and dried to
determine moisture content, which was accounted for
mathematically.
Pre-soaking of the sample TSPP dispersant solution ensured a more
efficient de-sliming process and to avoid potentially
under-reporting slimes content. |
Quality of assay data and laboratory tests |
The
nature, quality and appropriateness of the assaying and laboratory
procedures used and whether the technique is considered partial or
total.
For geophysical tools, spectrometers, handheld XRF instruments,
etc, the parameters used in determining the analysis including
instrument make and model, reading times, calibrations factors
applied and their derivation, etc.
Nature of quality control procedures adopted (e.g., standards,
blanks, duplicates, external laboratory checks) and whether
acceptable levels of accuracy (i.e., lack of bias) and precision
have been established. |
The
assay process employed by Base Resources includes a Sample
Preparation stage, completed by BTL staff, followed by a heavy
liquid separation (using lithium polytungstate: SG =
2.85g/cm3), completed at Kwale Operations’ site
laboratory.
Recent improvements to the sample preparation stage were made to
ensure industry best practice and to deliver a high degree of
confidence in the results. These included the following:
- A formalised process flow was generated, posted in all sample
preparation areas and used to train and monitor sample preparation
staff.
- Regular monitoring was completed by BTL senior geology
staff.
- Field samples were left in their bags for initial air-drying to
avoid sample loss.
- TSPP was introduced to decrease attrition time and improve
slimes recovery.A range of attrition times (with 5% TSPP) were
trialled and plotted against slimes recovery figures to determine
optimum attrition time (15 minutes).
- Staff were trained to use paint brushes and water spray rather
than manipulate sample through slimes screen by hand to remove the
potential for screen damage.
- A calibration schedule was introduced for scales used in the
sample preparation stage.
- Samples prepared and submitted systematically in 40 -sample
batches, with each batch routinely containing QC samples – one
standard, two field duplicates and two lab duplicates.
- Slimes screen number recorded to isolate batches should
re-assay be required due to poor adherence to procedure or to
identify screen damage.
- Various quality control samples were submitted routinely to
assure assay quality. A total of 95 field duplicates, 95
sample prep duplicates, 47 field standard samples, 61 lab repeats,
and an unspecified number of internal standards, repeats and blanks
have been assayed at Kwale Operations’ site laboratory.
|
Verification of sampling and assaying |
The
verification of significant intersections by either independent or
alternative company personnel.
The use of twinned holes.
Documentation of primary data, data entry procedures, data
verification, data storage (physical and electronic)
protocols.
Discuss any adjustment to assay data. |
The
Bumamani deposit is a moderate to low HM grade, dunal-style
accumulation that does not carry excessive mineralisation or suffer
from ‘nugget’ effects, typical of other commodities.
An external audit validation was completed for the HM analyses
included in the 2021 Bumamani Mineral Resources estimate by IHC
Robbins in 2020.
A total of ten twin drill holes were completed between the 2017 and
2018 drilling program, representing about 5.5% of the total
drillholes. These twins were used to quantify short-range
variability in geological character and grade intersections and
were placed throughout the deposit.
The spatially well-represented twin hole paired data shows very
good correlation considered material to the integrity/quality of
the resource data. |
Location of data points |
Accuracy and quality of surveys used to locate drill holes
(collar and down-hole surveys), trenches, mine workings and other
locations used in Mineral Resource estimation.
Specification of the grid system used.
Quality and adequacy of topographic control. |
Proposed
drill holes were sited on the ground using hand-held GPS.
After drilling, surveyors recorded collar positions via DGPS RTK
unit registered to local base stations. The accuracy of the
DGPS unit is stated at 0.02m in the X, Y and Z axes.
The survey geodetic datum utilised was UTM Arc 1960, used in E.
Africa. Arc 1960 references the Clark 1880 (RGS) ellipsoid and the
Greenwich prime meridian. All survey data used in the
2021 Bumamani Mineral Resources estimate dataset has undergone a
transformation to the local mine grid from the geodetic datum. The
local Grid was rotated at 42.5° which aligns the average strike of
the deposit with local North and is useful for both grade
interpolation and mining reference during production.
All drill collars were projected to the local LIDAR digital terrain
model captured over the resource area in 2018 at a 2x2m grid
spacing. This was performed prior to interpretation and model
construction to eliminate any elevation disparities for the block
model construction. |
Data
spacing and distribution |
Data
spacing for reporting of Exploration Results.
Whether the data spacing, and distribution is sufficient to
establish the degree of geological and grade continuity appropriate
for the Mineral Resource and Ore Reserve estimation procedure(s)
and classifications applied.
Whether sample compositing has been applied. |
The drill
data spacing from the 2017 and 2018 Bumamani Resource drilling
programmes was nominally 50m X, 100m Y and 1.5m Z. Variations
from this spacing resulted from terrain difficulties or ground
access issues.
This spacing and distribution is considered sufficient to establish
the degree of geological and mineralisation continuity appropriate
for the resource estimation procedures and classifications
applied.
A 1.5m downhole compositing has been applied for HM, slimes and
oversize in the interpolation processes. This is necessary in
Geovia Surpac software which cannot estimate grades directly from
the drillhole database. |
Orientation of data in relation to geological structure |
Whether the orientation of sampling achieves unbiased sampling
of possible structures and the extent to which this is known,
considering the deposit type.
If the relationship between the drilling orientation and the
orientation of key mineralised structures is considered to have
introduced a sampling bias, this should be assessed and reported if
material. |
With the
geological setting being a layered dunal/fluviatile sequence, the
orientation of the deposit mineralisation in general is
sub-horizontal. All drill holes were orientated vertically to
penetrate the sub-horizontal mineralisation orthogonally.
Hole centres were spaced nominally at 50m. This cross-profiles the
dune so that variation can be determined. Down hole intervals were
nominated as 1.5m. This provides adequate sampling resolution to
capture the distribution and variability of geology units and
mineralisation encountered vertically down hole.
The orientation of the drilling is considered appropriate for
testing the horizontal and vertical extent of mineralisation
without bias. |
Sample
security |
The
measures taken to ensure sample security. |
Sample
residues from the prep stage were transferred to pallets and stored
in a locked storage facility beside the warehouse at Kwale
Operations.
Residues from the Kwale Operations site laboratory were placed in
labelled jars and stored in numbered boxes. Boxes were placed into
a locked container beside the laboratory.
Sample tables are housed on a secure, network-hosted SQL
database. Administration privileges are limited to two BTL
staff: Exploration Superintendent and the Business Applications
Administrator.
Data is backed up every 12 hours and stored in perpetuity on a
secure, site backup server. Data is also backed up on Maxwell
GeoServices servers in Perth. |
Audits
or reviews |
The
results of any audits or reviews of sampling techniques and
data. |
Base
Resources’ Resources Manager, Mr. Scott Carruthers reviewed the
Bumamani geological interpretations, wireframes and assay and
mineralogy data interpolations. IHC Robbins Geological Services
Manager Greg Jones validated the resource data and reviewed the
completed block model. |
Section 2 Reporting of Exploration
Results
(Criteria listed in the preceding section also apply to this
section.)
Criteria |
JORC Code explanation |
Commentary |
Mineral tenement and
land tenure status |
Type, reference
name/number, location and ownership including agreements or
material issues with third parties such as joint ventures,
partnerships, overriding royalties, native title interests,
historical sites, wilderness or national park and environmental
settings.
The security of the tenure held at the time of reporting along
with any known impediments to obtaining a licence to operate in the
area. |
The Bumamani deposit is
situated on a Prospecting License (PL) 100% owned by Base Titanium
Limited – PL/2018/0119 located in Kwale County, Kenya. Base
Titanium Limited is a wholly owned subsidiary of Australian and
UK-listed resources company, Base Resources Limited.
The 88.7 km2 Prospecting License was granted on the 26th
of May 2018 for a three-year term ending 25th May 2021.
The PL is in good standing with the Kenya Ministry of Petroleum
& Mining at the time of reporting, with all statutory reporting
and payments up to date.
Local landowners are generally supportive of exploration activities
with over 90% of planned holes drilled.
The existing Special Mining Lease 23 lies within the Prospecting
license area and covers the Kwale Central deposit and some of the
Kwale South deposit but does not include the Bumamani deposit. The
Kenya Mining Act 2016 includes provision for the amendment of an
existing SML and for the conversion of an existing PL to SML. |
Exploration done by
other parties |
Acknowledgment and
appraisal of exploration by other parties. |
No known prior
exploration has been undertaken by other parties. |
Geology |
Deposit type,
geological setting and style of mineralisation. |
The Bumamani deposit is
part of the extensive coastal Plio-Pleistocene Magarini Formation,
which comprises aeolian dunal sands and clay-rich fluviatile units
that overlie down-faulted Jurassic and Tertiary formations.
The presence of a thin, discontinuous laterite layer seen at the
base of the dune sands is considered to indicate a change of
climate in contradistinction to the underlying fluviatile
sediments.
These units are locally enriched with heavy minerals, primarily
ilmenite, rutile and zircon as well as significant silicate gangue
in the lower fluviatile units. The hinterland ‘Mozambique Belt’
metamorphic formations are considered the likely HM feed source for
the Kwale deposits.
Exploration along the Kenyan coastline is yet to be successful in
terms of mineralised paleo-strandlines related to fossil marine
terraces, perhaps due to low wave energy levels caused by the
fringing reef acting as a breakwater, thus preventing effective HM
winnowing and trapping. |
Drill hole
Information |
A summary of all
information material to the understanding of the exploration
results including a tabulation of the following information for all
Material drill holes:
If the exclusion of this information is justified on the basis
that the information is not Material and this exclusion does not
detract from the understanding of the report, the Competent Person
should clearly explain why this is the case. |
Drilling by year (max,
min and average depths) used for the resource model build are as
follows:
See drill hole location plan, Figures 9 and 10.
All drill holes drilled vertically.
All collars projected to the LIDAR surface DTM
Exploration results are not being reported at this time. |
Data aggregation
methods |
In reporting
Exploration Results, weighting averaging techniques, maximum and/or
minimum grade truncations (e.g., cutting of high grades) and
cut-off grades are usually Material and should be stated.
Where aggregate intercepts incorporate short lengths of
high-grade results and longer lengths of low-grade results, the
procedure used for such aggregation should be stated and some
typical examples of such aggregations should be shown in
detail.
The assumptions used for any reporting of metal equivalent
values should be clearly stated. |
Exploration results are
not being reported at this time.
No bottom and top cut grades were employed.
No equivalent values were used.
No aggregation of short length samples used as sample interval was
consistently 1.5m. |
Relationship between
mineralisation widths and intercept lengths |
These relationships
are particularly important in the reporting of Exploration
Results.
If the geometry of the mineralisation with respect to the drill
hole angle is known, its nature should be reported.
If it is not known and only the down hole lengths are reported,
there should be a clear statement to this effect (e.g., ‘down hole
length, true width not known’). |
The deposit sequences
are sub-horizontal, and the vertically inclined holes are a fair
representation of true thickness. |
Diagrams |
Appropriate maps and
sections (with scales) and tabulations of intercepts should be
included for any significant discovery being reported These should
include, but not be limited to a plan view of drill hole collar
locations and appropriate sectional views. |
See figures 8-11. |
Balanced
reporting |
Where comprehensive
reporting of all Exploration Results is not practicable,
representative reporting of both low and high grades and/or widths
should be practiced to avoid misleading reporting of Exploration
Results. |
Exploration results are
not being reported at this time. |
Other substantive
exploration data |
Other exploration
data, if meaningful and material, should be reported including (but
not limited to): geological observations; geophysical survey
results; geochemical survey results; bulk samples – size and method
of treatment; metallurgical test results; bulk density,
groundwater, geotechnical and rock characteristics; potential
deleterious or contaminating substances. |
The proprietary MinMod
mineralogy technique, developed and employed by Base Resources,
comprises an XRF analysis of the magnetic and non-magnetic
fractions of each composite or sample, the results from which are
then back-calculated to determine in-ground mineralogy.
MinMod represents an improvement on the previous method (GeoMod)
that was not as effective at determining accessory minerals in the
Kwale assemblage. MinMod has been validated by external
quantitative analysis (QEMSCAN and SEM EDX) and is considered
sufficiently certified to support quoted resource confidence in
this report. |
Further work |
The nature and scale
of planned further work (e.g., tests for lateral extensions or
depth extensions or large-scale step-out drilling).
Diagrams clearly highlighting the areas of possible extensions,
including the main geological interpretations and future drilling
areas, provided this information is not commercially
sensitive. |
Test pits for bulk
sample mineralogy test work.
Generation of more Ore4 downhole composites for MinMod
mineralogy.
Infill drilling to improve Mineral Resource confidence in the
Indicated and Inferred areas.
Drilling of the Magaoni prospect which is a northern extension of
the Bumamani Deposit. |
Section 3 Estimation and Reporting of
Mineral Resources
(Criteria listed in section 1, and where relevant in section 2,
also apply to this section.)
Criteria |
JORC Code explanation |
Commentary |
Database
integrity |
Measures taken to
ensure that data has not been corrupted by, for example,
transcription or keying errors, between its initial collection and
its use for Mineral Resource estimation purposes.
Data validation procedures used. |
Field data was captured
in LogChief logging application and automatically validated through
reference to pre-set library table configurations.
Typing or logging code errors, duplication of key identifiers
(e.g., HOLE_ID, SAMP_ID) and conflicts in related tables (e.g.,
down-hole depth) are quarantined by the software and require
resolving immediately before logging can proceed.
The SQL Database also has identical automated validation features.
Data import is unsuccessful until these data issues are
resolved.
Field logging and survey data from the SQL database were imported
into Geovia Surpac for database build and sectional
interrogation.
Validation steps included a visual interrogation of collar versus
geology depths, a review of hole locations against the drilling
plan and a check for missing or duplicated logged fields and
outliers. Any spurious or questionable entries were resolved
by the supervising Geologist.
At the completion of each hole, an entry was made to the
hand-written drilling diary. The diary recorded the hole name,
date, depth, number of samples, time of start and finish, a
description of the location of the hole in relation to the last
hole and other things. Such a diary provides valuable evidence if
there is an error in-hole naming or surveying.
Several validation checks were made of sample preparation data to
ensure accurate data entry and application of correct procedure by
BTL staff. This included:
- comparison of pre- versus post-oven weights
- comparison of split weight versus de-slimed weight
- comparison of split weight versus field sample weight
- all sample preparation data were sorted by each individual
field and outliers investigated
Assay results were delivered via email in 45 sample batches from
the Kwale Operations site laboratory. These were in the form of CSV
text files and imported by batch number directly into the SQL
database tables where pre-set algorithms converted weights to
percentages and removed the moisture content. The calculated assay
results were then checked manually for missing records and out of
range or unrealistic values. |
Site visits |
Comment on any site
visits undertaken by the Competent Person and the outcome of those
visits.
If no site visits have been undertaken indicate why this is the
case. |
Base Resources’
Resources Manager Scott Carruthers, the Competent Person, has
visited the site several times to review assaying, geological
interpretation and resource estimation processes, which are
considered appropriate. |
Geological
interpretation |
Confidence in (or
conversely, the uncertainty of) the geological interpretation of
the mineral deposit.
Nature of the data used and of any assumptions made.
The effect, if any, of alternative interpretations on Mineral
Resource estimation.
The use of geology in guiding and controlling Mineral Resource
estimation.
The factors affecting continuity both of grade and
geology. |
The geological
interpretation and zoning were completed by the BTL Exploration
Superintendent by considering field logs, assays, microscopic HM
sink descriptions and mineralogy data.
The data spacing for the project is considered sufficient for grade
and mineralogical continuity.
Two mineralised geological zones and a basement zone were
identified and were used as constraints in the Mineral Resource
estimation.
The uppermost zone at Bumamani, referred to as Ore Zone 1, is a
dark brown, predominantly fine grained, well sorted silty sand with
very little induration. It is also characterised by clean,
polished HM with minimal gangue minerals.
Ore Zone 4, underlying Ore Zone 1 is a sandy-clay fluviatile unit
with low-level sorting and common lateritic fragments. The HM
from this zone contains more lateritic aggregates.
The Basement zone is a low-grade, clay rich, fluviatile unit with a
difficult to impossible washability. The HM from this zone is
notably enriched in gangue silicates.
For Ore Zones 1 and 4, a strong correlation between the field logs,
HM sink logs and XRF oxide chemistry and QEMSCAN mineralogy gives
confidence to these interpretations. |
Dimensions |
The extent and
variability of the Mineral Resource expressed as length (along
strike or otherwise), plan width, and depth below surface to the
upper and lower limits of the Mineral Resource. |
The Bumamani Mineral
Resource is approximately 1,600m along strike and 500-700m across
strike on average. The deposit thickness averages 10m. |
Estimation and
modelling techniques |
The nature and
appropriateness of the estimation technique(s) applied and key
assumptions, including treatment of extreme grade values,
domaining, interpolation parameters and maximum distance of
extrapolation from data points. If a computer assisted estimation
method was chosen include a description of computer software and
parameters used.
The availability of check estimates, previous estimates and/or
mine production records and whether the Mineral Resource estimate
takes appropriate account of such data.
The assumptions made regarding recovery of by-products.
Estimation of deleterious elements or other non-grade variables
of economic significance (e.g., sulphur for acid mine drainage
characterisation).
In the case of block model interpolation, the block size in
relation to the average sample spacing and the search
employed.
Any assumptions behind modelling of selective mining
units.
Any assumptions about correlation between variables.
Description of how the geological interpretation was used to
control the resource estimates.
Discussion of basis for using or not using grade cutting or
capping.
The process of validation, the checking process used, the
comparison of model data to drill hole data, and use of
reconciliation data if available. |
The Bumamani Mineral
Resource estimation was undertaken using Geovia Surpac version 6.8
software.
Inverse Distance Weighting to the power of three was used to
interpolate assay grades (HM, Slimes, Oversize) from the assay
composite string file.
Nearest Neighbour was used to interpolate the mineralogy data from
the mineralogy composite string file.
This is the maiden Mineral Resource estimate for the Bumamani
deposit and no previous estimates, or mining production records
have been prepared by Base Resources.
No assumptions have been made as to the recovery of
by-products.
The parent cell size used in the grade interpolation was half the
average drill hole spacing on the Y and X axes, which was 100m x
50m. The vertical thickness of the cell was the nominal average
drill sample interval i.e., 1.5m.
No assumptions were made behind modelling of selected mining
units.
No assumptions made about correlation between variables.
Validation was undertaken by swath plots, population distribution
analysis and visual inspection.
The geological zones were used to control the resource
estimates. Grade interpolations were controlled by ore
zone. |
Moisture |
Whether the tonnages
are estimated on a dry basis or with natural moisture, and the
method of determination of the moisture content. |
The Mineral Resources
estimate is on a dry tonnes basis. |
Cut-off
parameters |
The basis of the
adopted cut-off grade(s) or quality parameters applied. |
The economic cut-off of
Kwale Operations is between 1% and 1.5% HM, and historically the
Kwale Operations Mineral Resources estimate reporting focuses on a
1% HM cut-off grade. |
Mining factors or
assumptions |
Assumptions made
regarding possible mining methods, minimum mining dimensions and
internal (or, if applicable, external) mining dilution. It is
always necessary as part of the process of determining reasonable
prospects for eventual economic extraction to consider potential
mining methods, but the assumptions made regarding mining methods
and parameters when estimating Mineral Resources may not always be
rigorous. Where this is the case, this should be reported with an
explanation of the basis of the mining assumptions made. |
It is assumed that the
hydraulic mining method used at the neighbouring Kwale Operations
would be used. Moderate slime content and generally low
levels of induration provide support for this mining method. This
mining method is being re-assessed as part of the Kwale North Dune
PFS. |
Metallurgical factors
or assumptions |
The basis for
assumptions or predictions regarding metallurgical amenability. It
is always necessary as part of the process of determining
reasonable prospects for eventual economic extraction to consider
potential metallurgical methods, but the assumptions regarding
metallurgical treatment processes and parameters made when
reporting Mineral Resources may not always be rigorous. Where this
is the case, this should be reported with an explanation of the
basis of the metallurgical assumptions made. |
The existing
concentrator and separation plant at Kwale Operations are assumed
capable of processing the material with recoveries expected to be
aligned with present production. |
Environmental factors
or assumptions |
Assumptions made
regarding possible waste and process residue disposal options. It
is always necessary as part of the process of determining
reasonable prospects for eventual economic extraction to consider
the potential environmental impacts of the mining and processing
operation. While at this stage the determination of potential
environmental impacts, particularly for a greenfields project, may
not always be well advanced, the status of early consideration of
these potential environmental impacts should be reported. Where
these aspects have not been considered this should be reported with
an explanation of the environmental assumptions made. |
Coarse and fine
tailings are intended to be co-disposed together. Initially,
into the Kwale Central pit void and subsequently into the Bumamani
and Kwale North pit voids. |
Bulk density |
Whether assumed or
determined. If assumed, the basis for the assumptions. If
determined, the method used, whether wet or dry, the frequency of
the measurements, the nature, size and representativeness of the
samples.
The bulk density for bulk material must have been measured by
methods that adequately account for void spaces (vugs, porosity,
etc), moisture and differences between rock and alteration zones
within the deposit.
Discuss assumptions for bulk density estimates used in the
evaluation process of the different materials. |
A fixed dry bulk
density of 1.7 (t/m3) was assumed for the Mineral Resource
estimation, based on operational experience of mining the Kwale
Central Dune and South Dune deposits. |
Classification |
The basis for the
classification of the Mineral Resources into varying confidence
categories.
Whether appropriate account has been taken of all relevant
factors (i.e., relative confidence in tonnage/grade estimations,
reliability of input data, confidence in continuity of geology and
metal values, quality, quantity and distribution of the
data).
Whether the result appropriately reflects the Competent Person’s
view of the deposit. |
The classification of
the Indicated, and Inferred Mineral Resources was supported by the
uniform grid spacing of drilling, uncomplicated and consistent
geology, relatively good continuity of mineralisation particularly
along strike (and supported by the domain controlled variography),
confidence in the down hole drilling data and supporting criteria
as noted above.
As Competent Person, Base Resources’ Resources Manager Scott
Carruthers considers that the result appropriately reflects a
reasonable view of the deposit categorisation. |
Audits or
reviews |
The results of any
audits or reviews of Mineral Resource estimates. |
An internal review was
undertaken by Base Resources’ Resources Manager Scott Carruthers
with focus on the process and output of the geology interpretation,
database integrity, whether wireframes reflect the geological
interpretation, and model vs. drillhole grades. Mr.
Carruthers was satisfied with these facets.
An audit and review of the Bumamani resource data and block model
was undertaken by Greg Jones of IHC Robbins. Mr. Jones was
satisfied with the integrity of the drilling/assay data, block
model interpolated values and resource output. |
Discussion of
relative accuracy/ confidence |
Where appropriate a
statement of the relative accuracy and confidence level in the
Mineral Resource estimate using an approach or procedure deemed
appropriate by the Competent Person. For example, the application
of statistical or geostatistical procedures to quantify the
relative accuracy of the resource within stated confidence limits,
or, if such an approach is not deemed appropriate, a qualitative
discussion of the factors that could affect the relative accuracy
and confidence of the estimate.
The statement should specify whether it relates to global or
local estimates, and, if local, state the relevant tonnages, which
should be relevant to technical and economic evaluation.
Documentation should include assumptions made and the procedures
used.
These statements of relative accuracy and confidence of the
estimate should be compared with production data, where
available. |
Variography was
undertaken to determine the drill hole support of the selected JORC
classification.
Validation of the model vs drill hole grades by direct observation
and comparison of the results on screen.
The resource statement is a global estimate for the entire known
extent of the Bumamani deposit within the tenement area. |
Glossary
Competent Person |
The JORC Code requires
that a Competent Person must be a Member or Fellow of The
Australasian Institute of Mining and Metallurgy, or of the
Australian Institute of Geoscientists, or of a ‘Recognised
Professional Organisation’. A Competent Person must have a
minimum of five years’ experience working with the style of
mineralisation or type of deposit under consideration and relevant
to the activity which that person is undertaking. |
DTM |
Digital Terrain
Model. |
Indicated Resource or
Indicated |
An Indicated Mineral
Resource is that part of a Mineral Resource for which quantity,
grade (or quality), densities, shape and physical characteristics
are estimated with sufficient confidence to allow the application
of Modifying Factors in sufficient detail to support mine planning
and evaluation of the economic viability of the deposit. |
Inferred Resource or
Inferred |
An Inferred Mineral
Resource is that part of a Mineral Resource for which quantity and
grade (or quality) are estimated on the basis of limited geological
evidence and sampling. Geological evidence is sufficient to imply
but not verify geological and grade (or quality) continuity. It is
based on exploration, sampling and testing information gathered
through appropriate techniques from locations such as outcrops,
trenches, pits, workings and drill holes. |
Inverse distance
weighting |
A statistical
interpolation method whereby the influence of data points within a
defined neighbourhood around an interpolated point decreases as a
function of distance. |
JORC Code |
The Australasian Code
for Reporting of Exploration Results, Mineral Resources and Ore
Reserves 2012 Edition, as published by the Joint Ore Reserves
Committee of The Australasian Institute of Mining and Metallurgy,
Australian Institute of Geoscientists and Minerals Council of
Australia. |
LIDAR survey |
LIDAR is a remote
sensing technology that measures distance by illuminating a target
with a laser and analysing the reflected light to produce a
DTM. |
Measured Resource or
Measured |
A Measured Mineral
Resource is that part of a Mineral Resource for which quantity,
grade (or quality), densities, shape, and physical characteristics
are estimated with confidence sufficient to allow the application
of Modifying Factors to support detailed mine planning and final
evaluation of the economic viability of the deposit. |
Mineral Resources |
Mineral Resources are a
concentration or occurrence of solid material of economic interest
in or on the Earth’s crust in such form, grade (or quality), and
quantity that there are reasonable prospects for eventual economic
extraction. The location, quantity, grade (or quality), continuity
and other geological characteristics of a Mineral Resource are
known, estimated or interpreted from specific geological evidence
and knowledge, including sampling. Mineral Resources are
sub-divided, in order of increasing geological confidence, into
Inferred, Indicated and Measured categories. |
Minmod |
A company developed
mineralogy modelling technique, it comprises an XRF analysis of the
magnetic and non-magnetic fractions of each composite or sample,
the results from which are then back-calculated to determine
in-ground mineralogy. |
QEMSCAN |
An acronym for
Quantitative Evaluation of Materials by Scanning Electron
Microscopy, an integrated automated mineralogy and petrography
solution providing quantitative analysis of minerals and
rocks. |
QQ plot |
Quantile plot.
Used to graphically compare data distributions. |
RTK |
Real time kinematic
DGPS uses a base station GPS at a known point that communicates via
radio with a roving unit so that the random position error
introduced by the satellite owners may be corrected in real
time. |
SEM, SEM EDX |
A Scanning Electron
Microscope is a type of electron microscope that produces images of
a sample or minerals by scanning the surface with a focused beam of
electrons. EDX is short for energy dispersive X-ray and is
commonly used in conjunction with SEM. |
Variography |
A
geostatistical method that investigates the spatial variability and
dependence of grade within a deposit. This may also include a
directional analysis. |
XRF
analysis or XRF |
A
spectroscopic method used to determine the chemical composition of
a material through analysis of secondary X-ray emissions, generated
by excitation of a sample with primary X-rays that are
characteristic of a particular element. |
ENDS.
For further information contact:
James
Fuller, Manager Communications and Investor Relations
Base Resources
Tel: +61 (8) 9413 7426
Mobile: +61 (0) 488 093 763
Email: jfuller@baseresources.com.au
UK Media Relations
Tavistock Communications
Jos Simson and Gareth Tredway
Tel: +44 (0) 207 920 3150
About Base Resources
Base Resources is an Australian based, African focused, mineral
sands producer and developer with a track record of project
delivery and operational performance. The company operates
the established Kwale Operations in Kenya and is developing the Toliara Project in
Madagascar. Base Resources is an ASX and AIM listed
company. Further details about Base Resources are available
at www.baseresources.com.au
PRINCIPAL & REGISTERED
OFFICE
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Email: info@baseresources.com.au
Phone: +61 (0)8 9413 7400
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RFC Ambrian Limited
Stephen Allen
Phone: +61 (0)8 9480 2500
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Berenberg
Matthew Armitt / Detlir Elezi
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