Cobalt-Copper-Gold Potential of the Broken Hill Project
Released
Released
Announcement PDF
ASX ANNOUNCEMENT
Date: 5 May 2017
Number: 509/050517
EXPLORATION UPDATE
COBALT-COPPER-GOLD POTENTIAL OF THE
BROKEN HILL PROJECT, NSW
Whilst Impact Minerals Limited (ASX:IPT) remains firmly focussed on the discovery of high grade
nickel-copper-platinum group metal (PGM) cobalt mineralisation at its 100% owned Broken Hill Project
in New South Wales, a recent review highlighted the significant potential for two styles of stand alone
cobalt deposits (Figure 1 and see announcement 3rd March 2017).
Further review and synthesis of previous exploration data has now shown the potential for the two styles
of stand alone cobalt deposits to also host copper and gold. The two styles are:
1. Thackaringa style pyrite-cobalt deposits similar to the Thackaringa Cobalt deposits now being
considered for development (three deposits totalling 33 Mt at 0.08% cobalt, Figure 1); and
2. Ironstone related copper-cobalt-gold deposits similar, for example, to the large deposits at Starra
(Selwyn) and Ernest Henry in the Mt Isa region of Queensland.
The review has confirmed that there has been little systematic exploration for either of these two deposit
styles throughout Impact’s significant tenement holding in the Broken Hill region which cover some 517
square kilometres and about 100 kilometres of strike extent south of the Broken Hill Mine (Figure 1).
In particular it is evident that very few soil, rock chip and drill samples have been assayed for gold even
though it has long been known to be associated with both styles of mineralisation. For example at the
Copper Blow Prospect (near to but not on Impact’s tenements, Figure 1) historic drilling returned
intercepts of up to 11.8 metres at 6.7% copper, 1.9 g/t gold and 13 g/t silver in ironstone.
However, where more detailed work has been done by previous explorers, significant results have always
been returned and which have not been properly followed up. Two prospects on Impact’s tenement
holdings, Pine Creek and Copper King serve as examples for the Thackaringa style and ironstone-style
deposits respectively.
26 Richardson Street West Perth Western Australia 6005
Tel +61 (8) 6454 6666 Facsimile +61 (8) 6454 6667
Email info@impactminerals.com.au www.impactminerals.com.au
Figure 1. Impact’s exploration licences in the Broken Hill area showing priority cobalt targets
1. Thackaringa Style Deposits: Pine Creek
The Pine Creek Prospect is located 10 km west of Broken Hill and occurs in the same rocks that host the
Thackaringa deposits some 30 km to the south (Figure 1). Exploration in the 1980’s identified two northsouth trending units of felsic gneiss with extensive disseminated pyrite.
Two drill holes intersected the western gneiss unit and intersected extensive pyrite (5-20%) with cobalt
grades from 0.02% to 0.15% over at least 122 m and ended in mineralisation (Figure 2).
Assay results returned: 92 metres of 0.04% cobalt (true thickness of about 45 metres, Figure 2).
Of note, a 20 metre thick intercept of low grade gold occurs in the last 20 metres of the hole and is also
open at depth and associated with an increase in magnetite content (Figure 2). The best intercept in the
hole is 10 metres at 0.1 g/t gold and this is considered significant and worthy of follow up.
Figure 2. Geology and significant drill results of the Pine Creek Project. Note the mineralisation is open
at depth.
These are very encouraging results and may indicate the possibility of a large cobalt resource similar to
Big Hill-Pyrite Hill in the area that may also have significant gold credits. The airborne magnetic data
indicates two sub-parallel zones of interest that extend for at least one kilometre along trend on Impact’s
licence. In addition IP and EM data completed by the previous explorers identified many anomalies for
disseminated and massive sulphide targets that have not been followed up or drilled.
2. Copper King
The Copper King area is a series of historic copper occurrences and workings located in the east of
Impact’s tenements (Figure 1). Previous work has identified an anomalous copper-cobalt-gold trend up to
3.5 kilometres long which is in part defined by variably magnetic ironstone units. However the focus was
mainly on copper exploration and assays for both gold and cobalt are minimal.
Gold is mostly reported in rock chip samples with values reported of up to 0.75 g/t gold. Soil samples and
drill samples were not assayed for gold. Rock chip samples for cobalt range up to 0.13% cobalt but there
are no drill hole assays.
Three trenches dug in 2012 across parts of the trend near old workings returned up to:
23 metres at 1.5% copper and 4 g/t silver including 1.5 metres at 3.2% copper.
The shafts and workings were extensively sampled with good grades and returned up to 3.3% copper,
1.2% lead, 1.2% zinc and 40 g/t silver. This data and limited shallow drilling was used to define a small
non-JORC compliant resource estimate for copper. Gold and cobalt were not assayed.
The work done by previous explorers at these and other prospects has often been piecemeal and poorly
conceived and executed. There is clear scope within Impact’s licences to make multiple discoveries of
deposits of copper-cobalt-gold.
Other Targets
Magnetic ironstones that are potential hosts for cobalt-copper-gold mineralisation are identifiable in the
regional airborne magnetic data. An interpretation of this data and regional geological maps shows that
there are many strike kilometres of prospective ironstones within Impact’s ground (Figure 1). In addition
there are large tracts of ground that may contain the same rocks prospective for the Thackaringa style of
pyrite-cobalt(-gold) deposits (Figure 1).
NEXT STEPS
Impact remains firmly focussed on its exploration for deposits of high grade nickel-copper-PGM at
Broken Hill and follow up work for this style of deposit will be a priority, in particular follow up field
work in the eight areas identified by the VTEM survey in the Rockwell-Little Broken Hill Trend (see
announcement 3rd May 2017).
However the ongoing review of previous exploration data continues to reveal the potential for other styles
of mineralisation including cobalt-copper-gold and silver-lead-zinc, all of which deserve further work.
Accordingly Impact is considering various options to fund exploration for these other styles of deposit.
Dr Michael G Jones
Managing Director
The review of exploration activities and results contained in this report is based on information compiled by Dr Mike Jones, a Member
of the Australian Institute of Geoscientists. He is a director of the company and works for Impact Minerals Limited. He has sufficient
experience which is relevant to the style of mineralisation and types 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 (the JORC Code). Mike Jones has consented to the inclusion in the report of the matters
based on his information in the form and context in which it appears.
APPENDIX 1 - SECTION 1 SAMPLING TECHNIQUES AND DATA
Criteria
JORC Code explanation
Commentary
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.
Rock Chip Samples
Random rock samples were taken at surface which represented favourable geology and alteration to
known mineralisation in the region. Samples are variably weathered.
Soil Samples
Soil samples were taken at 50 m intervals from a hole 15-20 deep and sieved to -2mm to collect about
250 g of material.
Diamond Drilling
Diamond drilling was used to produce drill core either with a diameter of 63.5 mm (HQ) or 47.6 mm (NQ).
A handheld XRF instrument was used to analyse the drill core at 50 cm intervals.
Include reference to measures taken to ensure sample representivity and
the appropriate calibration of any measurement tools or systems used
Rock Chip Samples
Representative rock chip samples at each sample site weigh between 0.8 and 1.2 kg. Soil samples are
taken at a consistent depth below surface and sieved.
Soil Samples and Drill Samples
Sample representivity was ensured by a combination of Company Procedures regarding quality control
(QC) and quality assurance / testing (QA).
Examples of QC include (but are not limited to), daily workplace and equipment inspections, as well as
drilling and sampling procedures.
Examples of QA include (but are not limited to) collection of “field duplicates”, the use of certified
standards and blank samples approximately every 50 samples.
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
Rock Chip and Diamond Drill Samples
Rock samples and split diamond core were sent to Intertek Adelaide where they were crushed, dried and
pulverised (total prep) to produce a 25-30 g sub-sample for analysis by four acid digest with an ICP/AES
finish for ore grade base metal samples and either lead collection or nickel sulphide fire assay with AAS or
MS finish for gold and the PGMs. Weathered samples contained gossanous sulphide material. Soil
samples were sent to SGS Perth for analysis by the MMI digest.
The XRF data is qualitative only. A comparison between the XRF results and wet chemical assay data will
be completed on receipt of final results.
Sampling techniques
Drilling techniques
Drill sample recovery
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).
Method of recording and assessing core and chip sample recoveries and
results assessed
Diamond Drilling comprises NQ (47.6 mm diameter) and HQ (63.5 mm diameter) sized core. Impact
diamond core is triple tube and is oriented. Historical diamond core was not oriented.
Diamond core recoveries for all holes are logged and recorded. Recoveries are estimated to be
approximately >97% for the Red Hill Prospect. No significant core loss or sample recovery problems are
observed in the drill core.
Criteria
JORC Code explanation
Commentary
Measures taken to maximise sample recovery and ensure representative
nature of the samples
Diamond core is reconstructed into continuous runs on an angle iron cradle for orientation marking.
Depths are checked against the depth given on the core blocks and rod counts are routinely carried out
by the driller.
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.
No sample bias has been established.
Logging
Geological logging of samples followed company and industry common practice. Qualitative logging of
samples included (but not limited to); lithology, mineralogy, alteration, veining and weathering. Diamond
core logging included additional fields such as structure and geotechnical parameters.
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.
Magnetic Susceptibility measurements were taken for each 0.5 m diamond core interval.
For diamond core, information on structure type, dip, dip direction, texture, shape and fill material has
been recorded in the logs. RQD data has been recorded on selected diamond holes. Handheld XRF
analysis was completed at 50 cm intervals on diamond core.
Whether logging is qualitative or quantitative in nature. Core (or costean,
channel, etc) photography.
All logging is quantitative, based on visual field estimates. Systematic photography of the diamond core in
the wet and dry form was completed.
All diamond drill holes were logged in full.
The total length and percentage of the relevant intersections logged
Sub-sampling techniques and
sample preparation
Detailed diamond core logging, with digital capture was conducted for 100% of the core by Impact’s onsite geologist.
If core, whether cut or sawn and whether quarter, half or all core taken.
All core samples were sampled by half core. Selected intervals of quarter core will be selected for check
assays if required.
If non-core, whether riffled, tube sampled, rotary split, etc and whether
sampled wet or dry.
No RC drilling results are reported.
For all sample types, the nature, quality and appropriateness of the sample
preparation technique.
Company procedures were followed to ensure sub-sampling adequacy and consistency. These included
(but were not limited to) daily work place inspections of sampling equipment and practices, as well as
sub-sample duplicates (“field duplicates”).
Quality control procedures adopted for all sub-sampling stages to maximise
representivity of samples.
Laboratory QC procedures for rock sample and diamond drill core assays involve the use of internal
certified reference material as assay standards, along with blanks, duplicates and replicates.
Measures taken to ensure that the sampling is representative of the in situ
material collected, including for instance results for field duplicate/secondhalf sampling.
Rock and Soil Samples
Field duplicates were taken at selected sample sites.
Criteria
Quality of assay data and
laboratory tests
Verification of sampling and
assaying
Location of data points
Data spacing and distribution
JORC Code explanation
Commentary
Whether sample sizes are appropriate to the grain size of the material being
sampled.
Diamond Core Samples
Quarter core duplicate samples are taken randomly every 50 samples. Sample sizes at Red Hill are
considered adequate due to mineralisation style.
The nature, quality and appropriateness of the assaying and laboratory
procedures used and whether the technique is considered partial or total.
An industry standard fire assay technique for samples using lead collection with an Atomic Absorption
Spectrometry (AAS) finish was used for gold and aqua regia digest for base metals and silver.
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.
No geophysical tools were used to determine material element concentrations. A handheld XRF was used
for qualitative analysis only.
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.
Rock Chip Samples
For the rock chips, quality control procedures for assays were followed via internal laboratory protocols.
Accuracy and precision are within acceptable limits.
Diamond Drill Samples
Reference standards and blanks are routinely inserted into every batch of samples at a rate of 1 in every
50 samples.
The verification of significant intersections by either independent or
alternative company personnel.
The results have not been verified by independent or alternative companies. This is not required at this
stage of exploration.
The use of twinned holes.
No drilling results are reported.
Documentation of primary data, data entry procedures, data verification,
data storage (physical and electronic) protocols.
Primary assay data for rock chips has been entered into standard Excel templates for plotting in Mapinfo.
All historical drill data has been entered digitally by previous explorers and verified internally by Impact.
Discuss any adjustment to assay data.
There are no adjustments to the assay data.
Accuracy and quality of surveys used to locate drillholes (collar and downhole surveys), trenches, mine workings and other locations used in Mineral
Resource estimation.
Sample locations and drill holes were located by hand held GPS.
Specification of the grid system used.
The grid system for Broken Hill is MGA_GDA94, Zone 54.
Quality and adequacy of topographic control.
Standard government topographic maps have been used for topographic validation.
For the diamond holes, down-hole single shot surveys were conducted by the drilling contractor. Surveys
were conducted at 15 m, 30 m and then approximately every 30 m down-hole.
Data spacing for reporting of Exploration Results.
Sample spacing for the soil survey was on a 50 m by 50 m grid.
Reconnaissance drill spacing is approximately 200 m.
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.
Estimations of grade and tonnes have not yet been made.
Criteria
JORC Code explanation
Commentary
Whether sample compositing has been applied.
Sample compositing has not been applied.
Whether the orientation of sampling achieves unbiased sampling of possible
structures and the extent to which this is known, considering the deposit
type.
Not relevant to soil and rock chip results.
The orientation of mineralisation in RHD001 yet to be determined.
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.
Not relevant to soil and rock chip results or early stage exploration drill results.
Sample security
The measures taken to ensure sample security.
Chain of custody is managed by Impact Minerals Ltd. Samples for Broken Hill are delivered by Impact
Minerals Ltd by courier who transports them to the laboratory for prep and assay. Whilst in storage,
they are kept in a locked yard. Tracking sheets have been set up to track the progress of batches of
samples.
Audits or reviews
The results of any audits or reviews of sampling techniques and data.
At this stage of exploration a review of the sampling techniques and data by an external party is not
warranted.
Orientation of data in relation
to geological structure
SECTION 2 REPORTING OF EXPLORATION RESULTS
Criteria
JORC Code explanation
Commentary
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 Broken Hill Project currently comprises 1 exploration licences covering 100 km2. The tenement is held
100% by Golden Cross Resources Ltd. Impact Minerals Limited is earning 80% of the nickel-copper-PGE
rights in the licence from Golden Cross. No aboriginal sites or places have been declared or recorded over
the licence area. There are no national parks over the license area.
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 tenement is in good standing with no known impediments.
Exploration done by other
parties
Acknowledgment and appraisal of exploration by other parties.
There has been no significant previous work at this prospect.
Geology
Deposit type, geological setting and style of mineralisation.
Nickel-copper-PGE sulphide mineralisation associated with an ultramafic intrusion.
Mineral tenement and land
tenure status
Criteria
Drill hole Information
Data aggregation methods
JORC Code explanation
Commentary
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.
See Table in text.
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.
All reported assays have been length weighted. No top cuts have been applied. A cut-off of approximately
0.1% Cu, 0.4% Cu and 1.0% Cu has been applied for reporting of exploration results.
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.
High grade massive sulphide intervals internal to broader zones of disseminated sulphide mineralisation
are reported as included intervals.
The assumptions used for any reporting of metal equivalent values should
be clearly stated.
No metal equivalents have been reported.
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’).
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.
Refer to Figures in body of text.
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.
All results reported are representative
Balanced reporting
The orientation of mineralisation in RHD001 is yet to be determined.
Criteria
JORC Code explanation
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.
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
Commentary
Assessment of other substantive exploration data is not yet complete however considered immaterial at
this stage.
Follow up work programmes will be subject to interpretation of results which is ongoing.
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