AIM and Media Release
1 May 2019
BASE RESOURCES LIMITED
Mineral Resource for Kwale North Dune deposit
HIGHLIGHTS
- The Kwale North Dune Mineral Resources estimate is 171 million
tonnes at an average HM grade of 1.5% and contains 2.6Mt HM, based
on a 1% HM cut-off grade.
- The Kwale North Dune Mineral Resource is considered to have the
potential to add mine life to the Company’s existing Kwale
Operations.
- Base Resources will shortly commence a concept study to confirm
a business case, followed by a pre-feasibility study to determine
the economics, and therefore viability, of any mine life
extensions.
- Drilling on the North Dune will continue in 2019, aimed at
increasing Mineral Resources in the Measured and Indicated
categories as well as furthering our understanding of the
resource.
Graphics and figures referenced in this release have been
omitted. A full PDF version of this release, including all
graphics and figures, is available from the Company’s
website: www.baseresources.com.au.
African mineral sands producer, Base Resources Limited
(ASX & AIM: BSE) (Base Resources or the Company)
is pleased to release the maiden JORC 2012 North Dune Mineral
Resources estimate (the 2019 Kwale North Dune Mineral
Resource) at its 100% owned and operated Kwale Operations in
Kenya.
The Kwale Operation is currently based on the Central Dune and
South Dune deposits, with mining operations to date focused on the
Central Dune. A transition to the South Dune deposit is
scheduled for June 2019. On the basis of current Ore
Reserves, Kwale Operations will continue until mid-2022, which will
be extended to mid-2024 subject to approval of the South Dune
mining lease variation currently before the Kenyan Government.
The North Dune deposit was acquired by the Company as part of
the acquisition of the Kwale Project in mid-2010 but was excluded
from the project’s Mineral Resources on the basis of grade and then
prevailing economic conditions. A decision was taken to
re-evaluate the potential of the North Dune in 2018 in light of
improved economic conditions, refined resource definition
methodology and with insights gained from five years of operations
on the Central Dune. The 2019 Kwale North Dune Mineral
Resources estimate incorporates the results of an extensional and
infill drill program completed in 2018 (refer to the Company’s
announcements on 25 July
2018[1] and 18 October 2018[2])
as well as earlier programs.
The 2019 Kwale North Dune Mineral Resource is estimated to be
171 million tonnes (Mt) at an average heavy mineral
(HM) grade of 1.5% and 38% slimes (SL) and containing
2.6Mt HM, based on a 1% HM cut-off grade. The high slimes
content is likely to make the resource amenable to hydraulic mining
as is currently employed at the Kwale Operations. Mining
activity on the North Dune deposit would only require minimal
capital expenditure due to the close proximity of the existing
Kwale Operations processing facilities.
With the expectation that the resource will support modest
extensions to the Kwale Operations, a further drilling program will
now be completed on the North Dune deposit to allow a better
understanding of the resource and a study phase commenced to assess
the economics of potential mine life extensions. This will
proceed in parallel with the ongoing drilling programs in the Vanga
and Kwale East zones in pursuit of further mine life
extensions.
[Note (1): Refer to Base Resources’ ASX
announcement “Quarterly Activities Report – June 2018” released on
25 July 2018, which is available at
http://www.baseresources.com.au/investor-centre/asx-releases/.
Note (2): Refer to Base Resources’ ASX announcement
“Quarterly Activities Report – September 2018” released on
18 October 2018, which is available
at
http://www.baseresources.com.au/investor-centre/asx-releases/.]
Table 1: 2019 Kwale North Dune Mineral
Resources estimate at a 1% HM cut-off.
|
2019 Kwale North
Dune Mineral Resources
as at 1 May 2019 |
Category |
Material |
In Situ HM |
HM |
SL |
OS |
HM Assemblage |
|
|
|
|
|
|
ILM |
RUT |
ZIR |
|
(Mt) |
(Mt) |
(%) |
(%) |
(%) |
(%) |
(%) |
(%) |
Measured |
- |
- |
- |
- |
- |
- |
- |
- |
Indicated |
136 |
2.1 |
1.5 |
38 |
2 |
45 |
12 |
5 |
Inferred |
34 |
0.5 |
1.4 |
36 |
3 |
46 |
13 |
6 |
Total |
171 |
2.6 |
1.5 |
38 |
2 |
45 |
12 |
5 |
Table subject to rounding errors,
resources estimated at a 1% HM cut-off grade.
In addition, some potentially valuable mineralisation was
identified in the lower sandstone unit (which normally forms the
basement to the Kwale Central Dune and South Dune deposits), see
Table 2. The mineralogy of this unit is quite different to
the much younger overlying units reported in Table 1. If it
were to be mined, its saleable products would likely only be rutile
and zircon. A titano-haematite mineral is also present, but
due to its low TiO2 content it is not currently
considered to be marketable.
Table 2: 2019 Kwale North Dune lower
sandstone unit (zone 10) Mineral Resources estimate at a 1% HM
cut-off.
|
2019 Kwale North
Dune Mineral Resources
as at 1 May 2019 |
Category |
Material |
In Situ HM |
HM |
SL |
OS |
HM Assemblage |
|
|
|
|
|
|
Ti-Haem. |
RUT |
ZIR |
|
(Mt) |
(Mt) |
(%) |
(%) |
(%) |
(%) |
(%) |
(%) |
Measured |
- |
- |
- |
- |
- |
- |
- |
- |
Indicated |
- |
- |
- |
- |
- |
- |
- |
- |
Inferred |
61 |
1.5 |
2.5 |
42 |
2 |
45 |
7 |
3 |
Total |
61 |
1.5 |
2.5 |
42 |
2 |
45 |
7 |
3 |
Table subject to rounding errors,
resources estimated at a 1% HM cut-off grade.
Mineral Resources are reported in accordance with the JORC Code
(2012 edition). Accordingly, the information in these
sections should be read in conjunction with the respective
explanatory Mineral Resources information included in
Appendix 1.
Supporting information
The supporting information below is provided in accordance with
Chapter 5 of the ASX Listing Rules.
Section 1, Section 2 and Section 3 of JORC Table 1 can be found
in Appendix 1.
Requirements applicable to the Mineral
Resources estimate
A summary of the information used to prepare the 2019 Kwale
North Dune Mineral Resources estimate as presented in this report
is as follows.
The Kwale Project was initially owned by Tiomin Resources Inc.
(Tiomin) who conducted drilling in 1997 to establish Mineral
Resources estimates for the Central Dune, South Dune and North Dune
deposits. Base Resources purchased the Kwale Project in
mid-2010. At the time, Base Resources excluded the North Dune
deposit from the project on the basis of HM grade and then
prevailing economic conditions.
The Kwale North deposit is located on prospecting licence
2018-0119 comprising an area of 88.7km2 (formerly
special prospecting licence 173) which is located approximately 50
kilometres south of Mombasa and approximately 10 kilometres inland
from the Kenyan coast. The deposit is immediately north of
the operating Kwale Central Dune mine and the plant and
infrastructure comprising the Kwale Operations. The Kwale
Operations currently comprise two areas that contain economically
viable concentrations of heavy minerals on Special Mining Lease 23,
being the Central Dune and the South Dune (Figure 2).
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 silt
of around 25%. Heavy minerals, mainly ilmenite, rutile and
zircon, are locally concentrated and are abundant in some places,
giving rise to the deposits.
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 deposit. Five 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 VHM content of ~75% VHM.
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 valuable heavy mineral
(VHM) content, 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 the
former 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 it has a notably lower average
VHM content (44%).
Ore Zone 10 lies below Ore Zone 5 and is typically hosted in
weathered variants of the Mesozoic (Permo-Triassic) Duruma
Sandstones. Its mineralogy is predominantly titano-haematite
(<40% TiO2) with zircon enrichment in the
non-magnetic fraction.
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 was completed using the reverse
circulation, air core (RCAC) method and conducted in three
campaigns: November 2010,
December 2012 to April 2013 and June to October 2018 (Figure 5).
The predominantly 3 m sample
intervals in the 2010 and 2012/13 drilling was replaced by sampling
at 1.5 m intervals for the 2018 drill
program to provide greater control on geological boundaries.
Sample size averages close to 3 kg at this sample interval when
collecting 25% of the rotary splitter cycle. Samples are
dried, weighed, and screened for material less than 45 µm (slimes)
and +1 mm (oversize).
Approximately 100 grams of the screened sample is subjected to a
HM float/sink technique using the heavy liquid, lithium
polytungstate (LST with an SG of 2.85 gcm-3). The
resulting HM concentrate is dried and weighed as are the other
separated constituent size fractions (the minus 45 µm 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 are combined and, with the non-mag fraction, are
subjected to XRF analysis using a Bruker, S8 Tiger XRF.
Data from the mag and non-mag XRF analyses are processed through
the Minmod algorithm that runs approximately 100,000 iterations in
assigning key chemical species to a calculated mineralogy
determination.
Drill hole collar and geology data is captured by
industry-specific, field logging software with on-board
validation. Field and assay data are 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 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 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, 5 and 10) and basement (Figure 3).
Model cell dimensions of 50 m x
50 m x 1.5
m 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, composite
ID). Inverse distance weighting to a power of three was used
for primary assay fields whilst nearest neighbour was used to
interpolate index fields.
A fixed bulk density of 1.7 (t/m3) was applied to the
2019 Kwale North Dune Mineral Resources model. This bulk
density was selected based on operational experience in the Kwale
Central Dune deposit 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 Central 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 criteria used for classification was primarily the drill
spacing (predominantly 100 m x
100 m) and sample interval
(predominantly 1.5 m), with
consideration also given to the continuity of mineral assemblage
information. The estimates presented herein used a 1% HM
bottom cut because the economic cut-off grade at the nearby Kwale
Central Dune deposit mine is near to this, and resource estimates
for the Kwale Operation have historically been reported at this
cut-off grade.
Competent Person’s Statement
The information in this report that relates to 2019 Kwale North
Dune Mineral Resources is based on, and fairly represents,
information and supporting documentation prepared by Mr. Greg
Jones, who acts as Consultant Geologist for Base Resources and is
employed by IHC Robbins. Mr. Jones is a Member of the
Australasian Institute of Mining and Metallurgy and has sufficient
experience that is relevant to the style of mineralisation and type
of deposits under consideration and to the activity which he is
undertaking to qualify as a Competent Person as defined in the 2012
Edition of the Australasian Code for Reporting of Exploration
Results, Mineral Resources and Ore Reserves (JORC Code) ) and as
qualified person for the purposes of the AIM Rules for
Companies. Mr. Jones has reviewed this report and consents to
the inclusion in this report of the Mineral Resources estimates and
supporting information in the form and context in which it
appears.
Forward Looking Statements
Information in this report should be read in conjunction with
other announcements made by Base Resources to the ASX. No
representation or warranty, express or implied, is made as to the
fairness, accuracy or completeness of the information contained in
this report (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 report or its contents, including
any error or omission from, or otherwise in connection with,
it.
Certain statements in or in connection with this report 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.
Nothing in this report constitutes investment, legal or other
advice. You must not act on the basis of any matter contained
in this report 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
document 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
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 (RCAC) was used to
collect downhole samples for the project.
- Sample sub-splits are collected at 3m down-hole intervals for
the 122 holes drilled in 2012/2013 and 1.5 m down-hole intervals
for the 566 holes (drilled in 2018), using an on-board rotary
splitter mounted beneath the rig cyclone.
- Sample gates are set to collect 25% of the splitter cycle,
which delivers about 2.5 - 3.5 kg of sample per interval on
average.
- Duplicate samples are collected at the splitter for every 20th
sample by simultaneously with the original sample.
- A representative grab sample from the sample bags is 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 2012/2013 campaign were drilled with a RCAC
Wallis Mantis 75 drill rig using NQ drill tooling of about 76 mm in
diameter.
- 566 holes in the 2018 campaign were drilled with a more
modernised Mantis 80 drill rig, also using NQ drill bits.
- For the 2012/13 campaign, the mast was oriented vertically
(90º) by sight. For the 2018 drilling the rig mast was orientated
vertically by spirit level prior to drilling to adhere to best
practice for geological boundary delineation.
- Drilling is 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 is 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.
- Ground conditions of slightly damp with ~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 is recorded for all 15,681 fixed, down-hole
intervals and is conducted as drilling and sampling proceeds.
Logging is based on a representative grab sample that is panned for
heavy mineral estimation and host material observations.
- Logging codes are 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 are included to aid in the
subsequent geological modelling.
PROJECT |
Kwale
North |
HOLE_ID |
Hole Identifier |
DEPTH_FROM |
Depth from |
DEPTH_TO |
Depth to |
SAMMETHOD |
Sampling method:
Rotary splitter (ROT) |
SAMTYPE |
Sample Type
(SOIL) |
SAMP_ID |
Sample identifier |
SAMPLE_CONDITION |
Sample Quality |
LITH1_COL1 |
Major lithology colour
observed in grab sample |
IND_CODE |
Induration type
observed in grab sample |
IND_PCT |
Induration percent
estimate in grab sample |
HARDNESS |
Hardness estimate:
qualitative from 1 = no induration to 5 = refusal |
LITH1_CODE |
Major Lithology
observed in grab sample |
LITH1_PCT |
Major Lithology
percent observed in grab sample |
WASH |
Washability of the
grab sample |
EST_HM_PCT |
HM visual
estimate |
HM_GRAINSIZE |
Heavy mineral grain
size estimate |
LITH2_CODE |
Minor Lithology
observed in grab sample |
LITH2_COL2 |
Minor Colour observed
in grab sample |
LITH1_GRAINSIZE |
Dominant grainsize of
Major lithology |
P90_GRAINSIZE |
Coarsest grainsize of
Major lithology |
SORTING |
Estimated sorting
(grainsize) of the sediment in grab sample |
AS |
Assay "yes" or
"no" |
FACIES |
Sequence stratigraphic
unit |
FORMATION |
Domain code (Ore Zone
1, 4, 5, 10 and Base) |
COMMENT |
Commentary on
non-coded observations |
- A qualitative estimate of how representative a sample is of the
drilled interval is recorded by Base Titanium Limited (BTL)
field geologists whilst logging. This sample condition field
records whether the hole is 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 are logged routinely
under a reflected-light, stereoscopic microscope. This work
is carried to capture information relating to valuable heavy
mineral (VHM) content, mineralogy, HM grainsize and
quality.
Field |
Description |
SAMP_ID |
Sample identifier |
DOMINANT_HM |
Classification of
dominant VHM, VHM percent and minor non-VHM species |
SINK_QUALIFIER |
Additional qualifier
field for non-coded observations |
SINK_COMMENTS |
General comments
field |
SINK_LOGGED_BY |
Geologist
Initials |
SINK_LOGGED_DATE |
Date of Logging |
|
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 are 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 2.5-5 kg sample
contains in excess of 50 million grains of sand.
- The sample preparation flow sheet departs 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 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 by SGS staff at the Kwale 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,
- Tetrasodium Pyrophosphate (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 is 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 684 duplicate field samples,
675 duplicate sample preparation samples, 326 field certified
standard samples, and an unspecified number of internal SGS
laboratory standards repeats and blanks have been assayed at the
host SGS Kwale 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 Kwale North Dune 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 program
at a recommended rate of 5% of the total number of holes.
These twins are used to quantify short-range variability in
geological character and grade intersections and ideally should be
placed throughout the deposit.
- A total of twenty-six twin drill holes were completed during
the 2018 Kwale North Dune drilling program, which represents about
4.8% 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 are sited on the ground using hand-held
GPS. After drilling, surveyors record 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 is 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
Kwale North Resource dataset has undergone a transformation to the
local mine grid from the standard UTM Zone 37S (Arc 1960). The
local Grid is rotated 42.5o, which aligns the average
strike of the deposits with local North and is useful for both
grade interpolation and mining reference during production.
- All drill collars are projected to the local LiDAR survey,
digital terrain model (DTM), captured over the resource area
in 2018 at a 2x2 m grid spacing. This is 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 Kwale North Resource
drilling is nominally 100 m X, 100 m Y and 1.5 m Z.
Variations from this spacing result from terrain/traverse
difficulties and ground access.
- A sample spacing of 3 m, with occasional 1.5 m intervals at
geological contacts, was employed in the 2012/2013 drilling
campaign by BTL.
- A 1.5 m, down-hole block size was applied to model construction
and all previous 3 m drill data was de-surveyed to 1.5 m intervals
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 are orientated vertically to
penetrate the sub-horizontal mineralisation orthogonally.
- Hole centres are spaced nominally at 100 m. This cross-profiles
the dune so that variation can be determined. Down hole intervals
are nominated as 1.5 metres. 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 are transferred to pallets
and stored in a locked shed beside the warehouse at the Kwale
Operations.
- Residues from the Kwale Operations (SGS) HM Laboratory are
placed in labelled bags and stored in numbered boxes. Boxes
are 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: Edwin Owino (Exploration Superintendent), and Crispo Mwangi
(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 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 |
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 drilling work was completed on a Prospecting License (PL)
that is 100% owned by Base Titanium Limited – PL/2018/0119 located
in Kwale County, Kenya.
- The 88 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 drilling activities
with over 90% of planned holes drilled.
- The existing Special Mining Lease (SML23) lies within
the Prospecting license area and covers the Kwale Central and South
Orebodies. 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.
- 37 holes for a total of 1,824 m was achieved for the North
dune, at 3 m sampling intervals.
- A pre-stripped resource at 1% cut-off established (47 Mt @ 2.1%
HM).
- The current resource model omits the Tiomin data. This follows
a twin drilling analysis of the Tiomin Mud Rotary holes with Base
RCAC to determine relevance of historical data to the Kwale South
Dune resource 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:
- easting and northing of the drill hole collar
- elevation or RL (Reduced Level – elevation above sea level
in metres) of the drill hole collar
- dip and azimuth of the hole
- down hole length and interception depth
- hole length.
- 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 72 m, min 24 m, avg 56 m).
- Total 581 m drilled.
- 31 drill holes (depth: max 75 m, min 18 m, avg 60 m).
- Total 1,681 m drilled.
- 65 drill holes (depth: max 75 m, min 21 m, avg 54 m).
- Total 3,234 m drilled.
- 524 drill holes (depth: max 117 m, min 6 m, avg 46 m).
- Total 19,176m drilled.
- See drill hole location plan, Figure 5.
- 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 1.5 m 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.
|
|
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 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.
|
- Geological interpretation of nearby drilling to the East.
- Additional 100 x 100 m aircore drilling to extend
mineralisation in the open NW part of the deposit.
- Generation of six Ore Zone 5 QEMSCAN composites for a more
confident mineralogical modelling.
- Detailed tests to establish accurate bulk densities.
- Updated Mineral Resource estimate.
- Scoping study and a go or no-go decision made to progress to a
pre-feasibility study.
|
Section 3 Estimation and Reporting
Mineral Resources
(Criteria listed 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 is 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 are
imported into Datamine Discover (MapInfo) for sectional
interpretation. Validation steps include 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 are delivered via email in 45 sample batches from
SGS. These are in the form of CSV text files and imported by batch
number directly into the SQL database tables where pre-set
algorithms convert weights to percentages and remove the moisture
content. The calculated assay results are 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 Resource
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 (VHM)
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 the
former by a lateritic paleo-surface. It is unique
mineralogically by 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.
- Ore Zone 10 lies below Ore Zone 5 and is typically hosted in
weathered variants of the Mesozoic (Permo-Triassic) Duruma
Sandstones. It ranges in composition from a predominantly primary
titano-haematite (<40% TiO2) to a garnet dominant
suite. Some portions show a high zircon enrichment in the non-mag
fraction.
- 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 Kwale North Mineral Resource is approximately 6,300 m along
strike and about 1,200 m across strike on average, the deposit
thickness ranges from 9 m to 109 m.
|
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 Kwale North Dune computerised Mineral Resource estimation
was undertaken using Datamine Studio RM software.
- Inverse Distance Weighting (IDW) to the power of three was used
to interpolate assay grades (HM, Slimes, Oversize) from the drill
hole file.
- Nearest Neighbour (NN) was used to interpolate the composite ID
and mineralogy data.
- This is the maiden JORC 2012 Mineral Resource estimate for the
Kwale North Dune and no previous estimates, or mining production
records have been prepared by Base Resources. Prior to
acquisition of the Kwale Project by Base Resources, Tiomin prepared
and published a Mineral Resource Estimate of 116 Mt @ 2.1% HM using
a 0.5% HM cut-off grade.
- 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 X and Y axes, which was 100 m
x 100 m. The vertical thickness of the cell was the nominal average
drill sample interval i.e. 1.5 m.
- 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
estimates.
|
Moisture |
- Whether the tonnages are estimated on a dry basis or with
natural moisture, and the method of determination of the moisture
content.
|
- The resource 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 the operating Kwale Mine is between 1
and 1.5% HM, and historically the Kwale Operation’s 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.
|
- Prior to commencing any feasibility studies that may find to
the contrary, it is assumed that the hydraulic mining method used
at the neighbouring Kwale mine would be used. High slime
content and low levels, generally, of induration provide support
for this mining method.
|
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 the Kwale
Operation 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, in the absence of any feasibility studies,
would probably initially use the existing TSF for slime tails
storage (it has spare tails storage capacity due to efficient
processing practices) and the existing pit void for sand
tails. Once space is available, tailings would probably 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 resource estimation, based on operational experience of
mining the Kwale Central Dune Deposit.
|
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 the following criteria: drill hole spacing and the
distribution and influence of bulk samples.
- 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), and 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 of Base
Resources 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.
|
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.
|
GLOSSARY
Arc 1960 |
The commonly used Geodetic System in
East Africa, and is the reference frame used by the Global
Positioning System (GPS). |
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. |
DGPS |
Differential Global Positioning
System is a system to provide positional corrections to GPS
signals. DGPS uses a fixed, known position to adjust real
time GPS signals to eliminate pseudo range errors. |
DTM |
Digital Terrain Model. |
Indicated Resource |
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 |
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 neighborhood
around an interpolated point decreases as a function of
distance. |
JORC |
The Joint Ore Reserves Committee:
The Australasian Code for Reporting of Exploration Results, Mineral
Resources and Ore Reserves (‘the JORC Code’), 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. |
Measured Resources |
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. |
NQ |
Refers to the diameter of drill
rods. It is 69.9mm. Drill bits extend beyond this
resulting in a larger diameter hole. NQ is the most common
size rod used in mineral sand drilling. |
Ore Reserves |
Ore Reserves are the economically
mineable part of Measured and/or Indicated Mineral Resources. |
QEMSCAN |
Is 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 quantile plot. Used
to graphically compare data distributions. |
RL |
The term Reduced Level is denoted
shortly by 'RL'. National survey departments of each country
determine RL's of significantly important locations or
points. RL is used to describe the relative vertical position
of drill collars. |
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. |
UTM |
The Universal Transverse Mercator
(UTM) conformal projection uses a 2-dimensional Cartesian
coordinate system to give locations on the surface of the
Earth. |
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 |
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 |
UK Media Relations |
Base Resources |
Tavistock Communications |
Tel: +61 (8) 9413 7426 |
Jos Simson and Barnaby Hayward |
Mobile: +61 (0) 488 093 763 |
Tel: +44 (0) 207 920 3150 |
Email:
jfuller@baseresources.com.au |
|
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
Level 1, 50 Kings Park Road
West Perth, Western Australia, 6005
Email: info@baseresources.com.au
Phone: +61 (0)8 9413 7400
Fax: +61 (0)8 9322 8912
NOMINATED ADVISOR
RFC Ambrian Limited
Andrew Thomson / Stephen Allen
Phone: +61 (0)8 9480 2500
JOINT BROKER
Berenberg
Matthew Armitt / Detlir Elezi
Phone: +44 20 3207 7800
JOINT BROKER
Numis Securities Limited
John Prior / James Black / Paul
Gillam
Phone: +44 20 7260 1000