Heron Resources Limited (ASX:HRR “Heron” or the
“Company”) is pleased to advise that it has intersected
significant base-metal sulphide mineralisation at its wholly-owned
Woodlawn Zinc-Copper Project, located 250km south-west of Sydney,
New South Wales, Australia. The intercepts at both the G2 and Lisa
Lens positions extend the limits of the mineralisation in these
areas and will provide additional early stage production for the
operation.
Diamond drilling program recently
commenced targeting the G2 and Lisa Lens positions, 5 holes for
1,125m completed to date
G2 Lens (awaiting
assays)
6.0m from 120.4m of high-grade (up to
30% Zn from handheld XRF1 readings) massive and
stringer sphalerite+galena (high-grade G2 hanging wall zone)
WNDD0138
5.0m from 138.3m of Zn stringer
mineralisation (typical G2 main zone)
WNDD01387.4m from 129.0m of Zn stringer
mineralisation (typical G2 main zone)
WNDD0139
Lisa Lens (awaiting assays)
11.0m of Cu-rich massive sulphide from
202.0m in upper centre of lens (approx. 4 to 5% Cu from averaged
handheld XRF readings) providing further scope to extend Lisa
up-dip WNDD0135
The drilling extends both the G2 and
Lisa lenses. In particular, the intercepts at G2 extend the
mineralised zone closer towards the mine portal providing
potentially an additional shallow production source for the early
stages of the mine. Further drilling will be undertaken over
the next few weeks in this area to better define mineralisation
limits
Commenting on the intercepts, Heron Resources
Managing Director and CEO, Mr Wayne Taylor, said: “the results of
the drilling program to date continue to build off the 2017
drilling and are very encouraging, providing extensions to both
these lenses. The high grade G2 hanging-wall (G2HW) intercept
in WNDD0138 appears to be one of the better intercepts into G2
hanging-wall position we have seen and has the potential to boost
the early mine cash flow. The southern end of G2 Lens remains
open and further drilling is being planned to better delineate this
position. In addition, encouraging metallurgical test results
have now been received for the G2 and G2HW Lenses. The
program represents an important component of the early stages of
the Woodlawn mine development schedule”
G2 Lens Drilling
The G2 Lens is located adjacent to the planned
route of the decline at 120m to 150m below the surface and
represents the first underground ore that would be processed
through the plant. Initial metallurgical test work results on
3 composite samples (G2 Main, G2 Hanging Wall and G2 Copper) have
been received and show encouraging recoveries and concentrate
grades and will be the subject of a later market release following
the receipt of the full test work program results. Two diamond
holes for 341m have been completed recently on the southern extent
of the G2 Lens to better delineate this position which is open to
the south of WNDD0133 (see Figures 1-3). Both holes intersected
significant sulphide mineralisation:
6.0m from 120.4m of high-grade (up to 30% Zn
from hand-held XRF readings) massive and stringer sphalerite/galena
(high-grade G2HW), WNDD01385.0m from 138.3m of Zn stringer
mineralisation (typical G2 main zone), WNDD01387.4m from 129.0m of
Zn stringer mineralisation (typical G2 main zone), WNDD0139
These results are highly encouraging and extend
the G2 Lens some 20m to the south and down-dip in this area.
Importantly, the very high-grade G2 Hanging Wall (G2HW) position
has been extending to the south beyond WNDD0116, although its
continuity is expected to be variable. Assays are currently
pending, and follow-up drilling is planned. With the expanding
footprint, it is clear that G2 Lens is proving-up to be an
important addition to the early mine inventory. The drill rig
is currently drilling a geotechnical hole before recommencing at
the G2 Lens.
Lisa Lens Drilling
The Lisa Lens is located adjacent to the I Lens
in the upper-most horizon within the Woodlawn mineral system
(Figure 4) approximately 80 meters from the planned decline route
at 200-250m below the surface. The current program is
designed to better delineate the lens position with a significant
Cu-dominated intercept being received to date, located
approximately 40m up dip from previous drilling:
11.0m of Cu rich massive sulphide from 202.0m in
upper centre of lens (approx. 4 to 5% Cu from averaged hand-held
XRF readings), WNDD0135
This intercept combined with results of an
electromagnetic survey suggests the lens has a strike length of
about 35-40m and extends down dip approximately 120m. The
copper-rich intercept aligns with the Cu-dominated intercept in
historic hole W145 (8.0m @ 1.9% Cu). Such copper zones
typically occur on the southern edge of the Woodlawn lenses and it
is likely polymetallic mineralisation occurs along strike to the
north as noted in WNDD0104 (12.4m @ 20% ZnEq)2 and WNDD0015 (4.2m @
28.5% ZnEq)2.
Figure 1: Long section of the G2 Main Lens
showing interpreted lens shape, previous drilling and the two
recent drill intercepts. View to northeast.
http://www.heronresources.com/tsximages/20180419/190418_fig1.jpg
Figure 2: Long section of the G2 Hanging Wall
Lens showing interpreted lens shape, previous drilling and the
recent drill intercept in WNDD0138. View to
northeast.
http://www.heronresources.com/tsximages/20180419/190418_fig2.jpg
Figure 3: Massive sphalerite rich drill
core intersection from WNDD0138 in the G2 Hanging Wall
position. Handheld Niton XRF analysis of these sphalerite
rich massive sulphide zones returned an average of approximately
30% Zn (some 25 readings taken) over the interval 120.4 to
126.4m. The average zinc grade, however, is expected to be
slightly lower than this as the handheld XRF reading does not take
into account some internal gangue and other dilution. The
interval shown here is approximately 80cm long.
http://www.heronresources.com/tsximages/20180419/190418_fig3.jpg
Figure 4: Long section of the Lisa Lens
showing interpreted lens shape, the location of previous drill
intercepts and this program’s proposed infill holes. View to
northeast.
http://www.heronresources.com/tsximages/20180419/190418_fig4.jpg
About Heron Resources
Limited:
Heron’s primary focus is the development of its
100% owned, high grade Woodlawn Zinc-Copper Project located 250km
southwest of Sydney, New South Wales, Australia.
Compliance Statement (JORC 2012 and
NI43-101)
The technical information in this report
relating to the exploration results is based on information
compiled by Mr. David von Perger, who is a Member of the Australian
Institute of Mining and Metallurgy (Chartered Professional –
Geology). Mr. von Perger is a full time employee of Heron Resources
Limited and has sufficient experience, which is relevant to the
style of mineralisation and type of deposit 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 and “qualified person” as this
term is defined in Canadian National Instrument 43-101 (“NI
43-101”). Mr. von Perger has approved the scientific and technical
disclosure in the news release.
Zinc equivalent calculation
The zinc equivalent ZnEq calculation takes into
account, mining costs, milling costs, recoveries, payability
(including transport and refining charges) and metal prices in
generating a Zinc equivalent value for Au, Ag, Cu, Pb and Zn.
ZnEq = Zn%+Cu%*3.12+Pb%*0.81+*Au g/t*0.86+Ag g/t*0.03. Metal
prices used in the calculation are: Zn US$2,300/t, Pb US$ 2,050/t,
Cu US$6,600/t, Au US$1,250/oz and Ag US$18/oz. It is Heron’s
view that all the metals within this formula are expected to be
recovered and sold. Metallurgical metal recoveries used for
the formula are 88% Zn, 70% Pb, 70% Cu, 33% Au and 82% Ag; these
are based on historical recoveries at Woodlawn and supported by
metallurgical test work undertaken during the 2015-16 feasibility
study.
Appendix 1
Drill hole details for diamond drill holes
completed as part of the Phase V drill campaign.
Hole No. |
WMGEast (m) |
WMGNorth (m) |
WMGRL (m) |
Surface Dip |
WMG SurfaceAzimuth |
EOHDepth (m) |
Target |
WNDD0134 |
9074.3 |
19544.1 |
2795 |
-74 |
65.0 |
239.7 |
Lisa Lens |
WNDD0135 |
9074.3 |
19544.1 |
2795 |
-73 |
92.0 |
242.3 |
Lisa Lens |
WNDD0137W1 |
9074.3 |
19544.1 |
2795 |
-70 |
110.0 |
242.8 |
Lisa Lens |
WNDD0138 |
9157.8 |
19165.8 |
2794 |
-68 |
99.0 |
170.9 |
G2HW and G2 Lenses |
WNDD0139 |
9157.8 |
19165.8 |
2794 |
-59 |
125.0 |
170.8 |
G2HW and G2 Lenses |
Notes: WMG = Woodlawn Mine Grid
1 See Table 1 at the end of this report for details of the
hand-held XRF device used
2 WNDD0104: 12.4m @ 20.5 ZnEq (12% Zn, 1.6% Cu, 2.0% Pb, 0.7g/t
Au, 23g/t Ag); WNDD0015: 4.2m @ 28.5% ZnEq (17.7% Zn, 1.6% Cu, 5.0%
Pb, 28g/t Ag, 1.1g/t Au)
JORC 2012 Table 1
Section 1 Sampling Techniques and Data
(Criteria in this section applies to all
succeeding sections)
Criteria |
JORC Code explanation |
Commentary |
Sampling techniques |
- Nature and quality of sampling (eg 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.
|
- Samples from the diamond-core holes are being taken from HQ3
sized core and sampled on a nominal 1 metre basis taking into
account smaller sample intervals up to geological contacts.
The core is cut in along the core orientation line (where
available). Generally in massive sulphide zones one portion is
quartered for assaying, half the core is preserved for
metallurgical testing and the remaining quarter is retained as
reference material in the core trays. In non-massive sulphide
material half core is sampled.
- These sampling methods are standard industry methods and are
believed to provide acceptably representative samples for the type
of mineralisation encountered.
- A hand held XRF (Thermo Scientific Niton XL3t XRF Analyser)
device is used routinely to provide first pass Zn, Cu and Pb (plus
other elements) analyses of the core. This instrument is
regularly serviced and calibrated by qualified technicians and the
Company conducts its own QAQC on the results to confirm they are
reasonable. The results from this device are not considered
properly representative of the core intervals, however, they do
provide a broad indication of the likely grade of mineralised
zones.
|
Drilling techniques |
- Drill type (eg core, reverse circulation, open-hole hammer,
rotary air blast, auger, Bangka, sonic, etc) and details.
|
- Diamond-core drilling is being undertaken by Sandvik DE710 rigs
with mostly HQ3 sized core being drilled. Various techniques
are employed to ensure the hole is kept within limits of the
planned position. The core is laid out in standard plastic
cores trays.
|
Drill sample recovery |
- Method of recording and assessing core and chip sample
recoveries and results assessed.
|
- The core is transported to an enclosed core logging area and
recoveries are recorded. Recoveries to date have been better
than 95%. The core is orientated where possible and marked
with 1 metre downhole intervals for logging and sampling.
|
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.
|
- The diamond core is geologically logged by qualified
geologists. Geotechnical logging is also being undertaken on
selected sections of the core. Samples for metallurgical
testing are being kept in a freezer to reduce oxidation prior to
being transported to the metallurgical laboratory.
|
Sub-sampling techniques and sample preparation |
- For all sample types, the nature, quality and appropriateness
of the sample preparation technique.
|
- All core samples are crushed then pulverised in a ring
pulveriser (LM5) to a nominal 90% passing 75 micron. An
approximately 250g pulp sub-sample is taken from the large sample
and residual material stored.
- A quartz flush (approximately 0.5 kilogram of white,
medium-grained sand) is put through the LM5 pulveriser prior to
each new batch of samples. A number of quartz flushes are
also put through the pulveriser after each massive sulphide sample
to ensure the bowl is clean prior to the next sample being
processed. A selection of this pulverised quartz flush
material is then analysed and reported by the lab to gauge the
potential level of contamination that may be carried through from
one sample to the next.
|
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.
- Nature of quality control procedures adopted (eg standards,
blanks, duplicates, external laboratory checks) and whether
acceptable levels of accuracy (ie lack of bias) and precision have
been established.
|
- Sample preparation and assaying is being conducted through ALS
Laboratories, Orange, NSW with certain final analysis of pulps
being undertaken at the ALS Laboratory in Brisbane QLD.
- Gold is determined by 30g fire assay fusion with ICP-AES
analysis to 1ppb LLD.
- Other elements by mixed acid digestion followed by ICP-AES
analysis.
- Laboratory quality control standards (blanks, standards and
duplicates) are inserted at a rate of 5 per 35 samples for ICP
work.
|
Verification of sampling and assaying |
- The verification of significant intersections by either
independent or alternative company personnel.
- Documentation of primary data, data entry procedures, data
verification, data storage (physical and electronic)
protocols.
- Discuss any adjustment to assay data.
|
- An internal review of results was undertaken by Company
personnel. No independent verification was undertaken at this
stage.
- All field and laboratory data has been entered into an industry
standard database (DataShed) using a contract database
administrator (DBA) in the Company’s Perth office. Validation
of both the field and laboratory data is undertaken prior to final
acceptance and reporting of the data.
- Quality control samples from both the Company and the
Laboratory are assessed by the DBA and reported to the Company
geologists for verification. All assay data must pass this
data verification and quality control process before being
reported.
|
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.
|
- The drill collars were initially located with a combination of
handheld GPS and licenced surveyor using a DGPS system, with
accuracy of about 1m. The final drill collars are “picked up”
by a licenced surveyor with accuracy to 1 centimetre.
- While drilling is being undertaken, downhole surveys are
conducted using a downhole survey tool that records the magnetic
azimuth and dip of the hole. These recordings are taken
approximately every 30 metres downhole. As a check, certain
holes are also being surveyed with gyroscopic methods, with some 10
percent of holes drilled in the current program also surveyed by
this method after drilling has been completed.
|
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 diamond drilling is mostly following-up in various
directions from previous intercepts with a nominal spacing in the
range 20-40m. This drill hole spacing will be sufficient to
provide Mineral Resource estimates in the future.
|
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.
|
- The drilling orientation is designed to intersect the
mineralised lenses at a close to perpendicular angle. The
mineralised lenses are dipping at approximately 50-70 degrees to
the west and the drilling is approximately at 60 degrees to the
east. This will vary from hole to hole.
|
Sample security |
- The measures taken to ensure sample security.
|
- The cut core samples are secured in green plastic bags and are
being transported to the ALS laboratory in Orange, NSW via a
courier service or with Company personnel/contractors.
|
Audits or reviews |
- The results of any audits or reviews of sampling techniques and
data.
|
- A review and assessment of the laboratory procedures was under
taken by Company personnel in late 2014 resulting in some changes
to their sample pulverising procedure.
|
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 Woodlawn project is located 250km south-west of Sydney in
the state of New South Wales. The area is on the Great
Australian Dividing range and has an elevation around 800m above
sea-level. The mineral and mining rights to the project are
owned 100% by the Company through the granted, special (Crown and
Private Land) mining lease 20 (SML20). The lease has been
renewed to the 16 November 2029.
- The project area is on private land owned by Veolia who operate
a waste disposal facility that utilises the historical open-pit
void. An agreement is in place with Veolia for the Company to
purchase certain sections of this private land to facilitate future
mining and processing activities. A cooperation agreement is
also in place between Veolia and the Company that covers drilling
and other exploration activities in the area.
|
Exploration done by other parties |
- Acknowledgment and appraisal of exploration by other
parties.
|
- The Woodlawn deposit was discovered by the Jododex JV in 1970
and open-pit mining began in 1978 and continued through to 1987.
The project was bought outright by Rio Tinto Ltd (CRA) in 1984 who
completed the open-pit mining. Underground operations commenced in
1986 and the project was sold to Denehurst Ltd in 1987 who
continued underground mining up until 1998. The mineral
rights to the project were then acquired by TriAusMin Ltd in 1999
who conducted studies on a tailings re-treatment process and
further underground operations. Heron took 100% ownership of
the project in August 2014 following the merger of the two
companies. Some 980 surface and underground drill holes have
been completed on the project to date and various studies
undertaken.
|
Geology |
- Deposit type, geological setting and style of
mineralization.
|
- The Woodlawn deposit comprises volcanogenic massive sulphide
mineralisation consisting of stratabound lenses of pyrite,
sphalerite, galena and chalcopyrite. The mineralisation is
hosted in the Silurian aged Woodlawn Felsic Volcanic package of the
Goulburn sub-basin on the eastern side of the Lachlan Fold
Belt.
|
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:
|
- A table detailing the drill hole information is given in the
body of the report.
|
Data aggregation methods |
- In reporting Exploration Results, weighting averaging
techniques, maximum and/or minimum grade truncations (eg 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 reported assays are weighted for their assay interval
width. The majority of the assay interval widths are 1 metre, but
this weighting does take into account the non 1 metre intervals and
weights the average assay results accordingly.
- For the results reported here no weighting was included for
specific gravity (SG) measurements that have been taken for all
sample intervals as the samples within the intervals are of a
similar SG.
|
Relationship between mineralization 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.
|
- The massive sulphide zone intercepted in the drilling to date
is at an angle to the drill axis and therefore the true width is
estimated to be some 0.8 of down-hole width. That is, a
down-hole intercept of 16m equates to a true width of 12m.
This is only an approximation at this stage and will be better
estimated as the orientation of the Lenses is better defined.
|
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.
|
- Where relevant, a diagram showing the hole positions relevant
for current phase of exploration is included in the release.
Other maps and diagrams showing the location of the Woodlawn
Project are included in other recent Company releases.
|
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
Results.
|
- The reporting is considered to be balanced and all relevant
results have been disclosed for this current phase of
exploration.
|
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.
|
- Selected drill holes are being cased with 50 millimetre PVC
tubing for potential down-hole DHEM surveying which is undertaken
on the majority of the holes drilled.
- Geotechnical logging is undertaken nominally 25m either side of
the massive sulphide lenses.
- Archimedes method SG measurements are determined for all
sampled intervals.
|
Further work |
- The nature and scale of planned further work (eg tests for
lateral extensions or depth extensions or large-scale step-out
drilling).
|
- The fifth phase of drilling at Woodlawn commenced in March 2018
with some 2,000 to be drilled. The program was primarily designed
to infill and expand the Lisa and G2 Lens positions. A number of
geotechnical holes are also planned as part of this program.
- The results of the program are being assessed as they come to
hand and adjustments to the program made as is warranted.
|
For further information, please visit www.heronresources.com.au or contact:
Australia:
Mr Wayne Taylor
Managing Director and Chief Executive Officer
Tel: +61 2 9119 8111 or +61 8 6500 9200
Email: heron@heronresources.com.au
Jon Snowball
FTI Consulting
+61 2 8298 6100
jon.snowball@fticonsulting.com