The Einasleigh Project is located 250k south west of Cairns in north Queensland, and 165k south west of Mt Garnet (approximately 200k by road from Mt Garnet). The projects are all within a radius of 20k of the town of Einasleigh. The company has purchased a caravan park on the outskirts of the township and established a permanent exploration and development camp on this site.
Deposits within the Einasleigh area include Kaiser Bill, Chloe & Jackson, Dreadnought, Historic Einasleigh Copper Mine, Teasdale, Railway Flat in addition to numerous other prospects. These have been discovered by various explorers using methods ranging from soil sampling through to drilling.
Substantial deposits of copper, zinc, lead, silver and minor gold have been located within the project area. Copper Strike Limited defined several of the larger prospects that contain Mineral Resources, such as Kaiser Bill, Einasleigh Copper Mine, Chloe & Jackson-Stella and Railway Flat.
A number of other prospects are known such as Teasdale and Bloodwood Knoll and numerous other mineral occurrences in the area, many of which appear to also have potential. The project area represents a possible new production centre especially with the upside potential indicated for an increased Mineral Resource base, particularly for copper. The Einasleigh Copper Mine – Kaiser Bill copper-gold deposits are iron oxide copper gold (IOCG) deposits similar in style to those developed in the world-class Cloncurry district of north-west Queensland.
Einasleigh Project – Prospect Locations
CSD acquired the assets of Snow Peak Mining Pty Ltd (SPM), including the Einasleigh copper projects, in April 2016. SPM had acquired the projects from Kagara Limited (Kagara) in late 2013. Kagara had acquired the Einasleigh copper projects from Copper Strike Limited (Copper Strike) in late 2011.
Wanguo International Mining Group (Wanguo) signed a Farm-in Agreement with SPM in July 2014 and this was later assigned to CSD after CSD acquired the assets of SPM.
From 2005 to 2010, Copper Strike focused activity on resource evaluation at the Einasleigh Copper Mine, and Kaiser Bill and Chloe & Jackson prospects. Regional programs were defined to evaluate further prospects and considerable drilling was undertaken.
Wanguo collected approximately 1500 soil samples in 2015 from the Surveyor, Balcooma and Einasleigh areas, as well as completing approximately 60 line-kilometres of ground-based Induced Polarisation (IP) surveys over various prospects within the Einasleigh project area including Black Rock Gossan, Teasdale, Railway Flat, Kaiser Bill East, Kaiser Bill West and Chloe & Jackson. A further 9.52 line-kilometres of ground magnetics over Chloe – Jackson were also completed. The results of this work were incorporated into the programs of CSD in 2017 and 2018.
Base metal deposits in the Einasleigh area occur within the Paleoproterozoic Georgetown Inlier. The oldest rocks in the region, the lower Etheridge Group, locally represented as the Einasleigh Metamorphics, formed at c.1700 Ma (Black et al, 2005).
The Einasleigh Metamorphics comprise calc-silicate and metasedimentary biotite gneiss with extensive amphibolite intrusions. Metamorphic grade is up to granulite facies but is commonly amphibolite facies. Palaeozoic thermal events are evidenced by Siluro-Devonian granite, and Permo-Carboniferous Caldera formation and related porphyry intrusions.
Dating of the Chloe Deposit by Geoscience Australia give Pb-Pb model ages of 1,644 Ga and 1.678 Ga. The Einasleigh Copper Deposit contains molybdenite and monazite, which give a age suggesting the mineralisation in its current structural setting formed at ca. 1400 Ma. Kaiser Bill has not been effectively dated.
Extensive mapping of the Einasleigh region shows that the sequence contains a complex stratigraphy, with several mappable units; however, the relationships among these units are conjectural due to structural complexity.
In a regional framework, the thinly bedded pelites, psammites and calc-silicates that form the basal Boree Unit, together with the main calc-silicate unit and leucogneiss are grouped as the “calc-silicate suite”, while biotite gneiss and pelite units together form the “biotite gneiss suite”. Thin to massive amphibolite units, often with fine-grained margins indicative of likely intrusive contacts, are interpreted as mafic sills intruding the metasedimentary sequence.
Einasleigh Project Regional Geology Map
Historic Einasleigh Copper Mine Deposit
The historic Einasleigh Copper Mine is situated about one kilometre north of Einasleigh Township, on the west bank of the Copperfield River at its junction with the Einasleigh River. It is located about 500 metres north of the Copperfield Gorge.
Historically, a range of activities have occurred at the mine, including:
- Between 1901 and 1921, underground mining was undertaken intermittently by a succession of companies. The mine was abandoned in 1922 and the workings allowed to flood.
- In 1966-67, Carpentaria Exploration drilled two diamond holes, with one hole intersecting low grade (<1% Cu) copper mineralisation.
- In 1968, Trans Australian Exploration undertook geological mapping, induced polarisation (IP) surveying and ground magnetics around the mine but not over the mining lease. One diamond hole, drilled to test an IP anomaly, intersected traces of mineralisation (8.8 m at 0.04% Cu).
- From 1970 to 1972, a joint venture between Combined Mining and Exploration (CME) and North Interior Explorations dewatered the shaft and obtained access to the underground mine. A program of underground drilling, sampling and mapping was performed. Although the drill holes intersected some significant copper mineralisation, the results concluded it was not economically viable. CME estimated that the deposit contained 260,660 t at 2.13% Cu adjacent to the old stopes.
- From 1976 to 1995, regional exploration programs were undertaken in the vicinity of the Einasleigh Copper Mine by CRA and BHP Minerals. No specific work was undertaken at the old mine, which was held under a Mining Lease during much of that period.
- In 2002, EPM 13072 which included the Einasleigh Copper Mine, was granted to Teck Cominco Australia. Teck Cominco undertook ground magnetics and moving-loop electromagnetic (EM) surveying at Einasleigh and drilled one diamond hole, ECD01, to test two resulting conductors. Low grade copper mineralisation was intersected but not enough to warrant further work by Teck Cominco.
- Late 2004, EPM 13072 transferred to Copper Strike Limited following the successful float of Teck Cominco’s assets in the Georgetown area.
Geology and Mineralisation
Copper mineralisation at the Einasleigh Copper Mine occurs as chalcopyrite associated with variable amounts of pyrrhotite and lesser pyrite within altered quartz-sulphide breccias. Alteration mainly consists of amphibole (actinolite)-magnetite-garnet-chlorite-barite replacing the quartz feldspar-biotite gneiss host rock. Brecciation in the host rocks and within the massive sulphide mineralisation is common.
The mineralisation/alteration envelope delineated by Copper Strike beneath the old mine has a general synformal shape with a gentle south-southwest plunging axis. Copper Strike defined this basic morphology by modelling down-hole Electro-Magnetic (EM) data collected from each drill hole. A model of the conductive plate identified by the EM survey, specific to each hole, was constructed and then merged with all the other hole-specific plate models. This provided the broadly synformal shape. Three holes, numbered END 022, 023 and 026, were then drilled to test the interpretation and broadly confirmed it. The synformal structure is also reflected by the morphology of the alteration zone and by surface geological mapping of the outcrop of the alteration and mineralisation in the Einasleigh River north of the old workings (i.e. up plunge).
The mineralised zones which form the western limb of the synform dipping moderately (20° to 60°) to the east and the eastern limb varies from steep westerly dipping to overturned steep easterly dipping. The best copper grades appear to occur close to the keel of the structure and in the lower parts of the eastern limb. Contacts between barren host rock and significant mineralisation (say >1% Cu) are generally very sharp on the eastern limb and more diffuse on the western limb. Old mine plans show that mineralised bodies ‘pinched and swelled’ over distances of a few metres and occasionally split into separate lodes.
The old mine was geologically mapped by CME. Two mineralised zones were developed in the old mine. The Main Orebody (or ‘Big Orebody’) strikes at 210° and varies from less than 1 m to more than 25 m in width. In the upper levels this body dips at about 60° to the southeast but below Level 4 it dips at 80° to the northwest. The Main Orebody is correlated with the eastern limb of the mineralised zone tested by Copper Strike. A second mineralised zone, the New Orebody, occurs about 75 m to the northwest of the Main Orebody. Its extent and orientation are not well-defined but it appears to have approximately the same strike as the Main Orebody and a dip of perhaps 60° to the southeast. This zone may correlate with the western limb of the mineralised zone tested by Copper Strike.
Three named faults that appear to offset the mineralised zones are shown on the level plans. The northernmost fault is the Breccia Fault which was exposed in the main cross cut on the upper levels of the mine. This structure dips at about 75° to 80° towards the southeast or south-southeast. It truncates the southern end of the New Orebody and the northern end of the Main Orebody but its throw is unknown. The Footwall Fault occurs a few metres to the south of, and is subparallel to, the Breccia Fault. It is likely that the two faults merge, somewhere to the northeast of the mine. The Footwall Fault appears to displace the Main Orebody by about 35 m on Level 2 and a sinistral movement is inferred. A third fault, the Compound Fault was only mapped on two levels and whilst there appears to be some local displacement of the Main Orebody adjacent to this fault, its wider significance is unknown.
The mineralised domain model for the Einasleigh Copper Deposit is depicted below.
Einasleigh Copper Deposit – Mineralised Domain Model
Einasleigh Copper Mine Deposit – Historical Exploration
Copper Strike acquired an exploration licence over the area in 2004 and began a program of diamond drilling late in 2004, searching for a down-plunge extension of the mineralisation.
The drilling program identified a new massive sulphide body that has not been exploited by mining.
This program included 26 drill holes using a UDR 650 drill rig and is summarized below. Drill holes missing from the numeric sequence in the table were abandoned before intersecting the target zones. In most drill holes the upper 36 m was drilled using reverse circulation. The holes were then cased-off with steel casing and continued with diamond drilling using a conventional NQ2 system with a standard tube. In all drill holes, except ECD001, drill core was orientated at nominal 30 m intervals using a tapered spear with a chinagraph point.
Drill core samples, with exceptions listed below, were collected over 1 m intervals beginning and ending on metre markings. Exceptions were ECD001 where samples were collected over 2 m intervals, END001 where one sample was over 0.5 m and END003 where three samples were <1 m and one sample was > 1 m.
All significant mineralised intercepts were sampled over 1 m intervals. The selection of intervals for sampling was determined by the presence of chalcopyrite, regardless of estimated percentage, and/or alteration minerals. The core was sawn in half, bagged and submitted to ALS Chemex’s laboratory in Townsville for preparation using the following procedures and techniques:
- Coarse crushing of drill samples to 70% nominal -6 mm (ALS Chemex code CRU-21).
- Riffle split to a maximum 3 kg and pulverise split to 85% passing 75 microns or better (ALS Chemex code PUL-23).
- 200 g – 300 g of material scooped from the pulverised sample to become a master pulp. From that, 25 g to 30 g of material was scooped for Au assaying in Townsville by fire assay with an AAS finish (ALS Chemex code Au-AA25).
- In addition, 5 g to 10 g of material was scooped from the pulverised sample and sent to ALS Chemex’s Brisbane laboratory for ICP analysis. ‘Near total’ digestion of sample by HFHNO3-HClO4 and HCl leach and analysis by ICPAES. Elements analysed were Ag, Al, As, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, Rb, S, Sb, Sr, Ti, V, W and Zn (ALS Chemex code ME-ICP61s).
- All samples reporting ≥10,000 ppm Cu by ICPAES were then subject to ore grade analysis by Aqua Regia digest with an AAS finish (ALS Chemex code Cu- OG46). In these cases, the results of the ore grade analysis were used in the resource estimate.
In August 2005, the result of this drilling and sampling regime resulted in Copper Strike contracting Golder Associates Pty. Ltd. (Golder) to compile a first-pass geological model and Mineral Resource estimate for the new deposit.
Copper Strike 2004-2005 Drill Hole Data
Einasleigh Copper Deposit 2004-2005 Drill Hole Locations
Einasleigh Copper Mine Deposit Mineral Resource
The most recent Mineral Resource for Einasleigh Copper Mine was reported in the 2006 Copper Strike Annual Report in accordance with the JORC Code 2004. The Mineral Resource estimate has not been updated to comply with the JORC Code 2012 on the basis that the information used for the estimate has not materially changed since it was last reported.
The Mineral Resource estimate is summarised below.
The Mineral Resource was estimated using a total of 26 drill holes that were pre-collared down to an average depth of 36 m with reverse circulation and then completed to final depth with NQ2 sized diamond core.
The drill holes were geologically logged for key geology and mineralisation domains and were then half core sampled, typically in 1 m lengths, and samples were sent to the ALS Chemex laboratory in Townsville for assaying. The assaying method used for samples within the Townsville laboratory was 50 g fire assay with an Atomic Absorption Spectrum (AAS) finish, a split of each sample was also sent to the ALS Chemex laboratory in Brisbane for multi-element analysis using the ICPAES method.
Golder Associates consultants estimated the Mineral Resources using ordinary kriging and no cutting of high-grade assay outliers was assessed as necessary. The Mineral Resource was reported at a cut-off grade of 1.0% Cu.
The sampling and assaying methods and the grade estimation method used were appropriate for the Einasleigh style of mineralisation.
Einasleigh Copper Deposit Mineral Resource Estimate September 2006
1Mineral Resources are reported above a 1.0% Cu cut-off grade
Einasleigh Copper Mine Deposit – Mineral Resource/Exploration Upside
The Einasleigh copper deposit shows exploration upside along strike of the currently defined mineralisation where a fold hinge is interpreted to exist. Further drilling would be required to confirm this interpretation.
Chloe & Jackson Project
The Chloe and Jackson project is located 20 kilometres south-west of the township of Einasleigh. The two deposits are part of the Chloe to Dreadnought Trend, containing a Pb-Zn-Ag mineral system, present as a series of deposits that have geological similarities to zinc-rich skarn deposits in terms of host rocks, alteration, mineralogy and chemistry.
Gossans of the deposits were discovered in the early 1970s by Otter Exploration NL (Otter) after following up on stream sediment anomalies.
Otter entered into a Joint Venture with CRA in the mid-1970s, with Otter owning the tenement and CRA conducting the exploration activities. Exploration under the Joint Venture was conducted over the prospect area through to the early 1980s included geological mapping, excavation of costeans, soil sampling, ground magnetics and drilling over the outcropping gossans.
A total of ten diamond drill holes were drilled below the gossans, with the best intersection being from hole MD8 with 15.6 m at 5.9% Zn, 2% Pb, 41 g/t Ag, 0.3% Cu from 63.1 m. Only four holes intersected significant mineralisation. A mining lease was granted to Otter in the early 1980s covering the main prospects, and in 1983, CRA pulled out of the Joint Venture to focus on projects elsewhere.
There was no further exploration over the prospect until 2003 when Teck Cominco took ownership. Teck completed mapping, soil sampling, a ground magnetic survey, fixed loop surveys and a single diamond drill hole. Extensive drilling over the prospect was conducted after the project was transferred out of Teck to float Copper Strike who completed 152 drill holes between 2006 and 2010.
In 2017, 20 holes were completed by CSD at the Jackson Prospect and five holes at the Young Prospect. At Jackson, the holes provided support for reporting Mineral Resources in accordance with the JORC Code 2012. At Young, the holes were designed to follow up historical intersections including 14 m at 4.68% Zn. The drill results suggest that the mineralisation is a sheet–like structure that steepens at depth.
The Chloe – Jackson – Dreadnought trend is structurally complex with multiple generations of folds mapped and a number of orientations of fault structures. The mineralisation lenses are generally thin and, in some areas, multiple lenses are evident. The Stella prospect is now believed to be part of the Jackson deposit.
Chloe and Jackson have similar alteration and mineralisation assemblages and overprinting relationships. There are at least four main groups of mineral assemblages: an outer, usually barren quartz-epidote-zoisite assemblage; a garnet-dominated assemblage usually with pale sphalerite, a pyrrhotite-dominated assemblage usually in the core of the thickest mineralisation, and a magnetite-dominated assemblage which appears to be a retrograde and oxidized version of the pyrrhotite mineralisation. The Chloe-Jackson Deposit structure is depicted below.
Chloe and Jackson – Modelled Mineralisation Domains
Chloe & Jackson Deposit Mineral Resource
In June 2018, the Chloe & Jackson Mineral Resource estimates were reported in accordance with the JORC Code 2012.
A total of 249 drill holes comprising a combination of reverse circulation and NQ2 sized diamond core were used in the estimation.
The drill holes were geologically logged for key geology and mineralisation domains and were then half core sampled, typically in 1 m lengths, and samples were sent to the ALS laboratories in Brisbane for assaying. The assaying method used for samples was ME-ICP61 to provide a suite of multi-element analyses. Gold was assayed for via a 30 g fire assay with a flame AAS finish.
A range of top cuts was applied based on the assessment of grade populations within the datasets evident in plotted histograms and log probability plots. Density was estimated using a regression formula based on a dataset of 3,120 discrete density samples.
Mining Associates consultants estimated the Mineral Resources using ordinary kriging. The Mineral Resource was reported at a cut-off grade of 1.0% Zn.
The sampling and assaying methods and the grade estimation method used were appropriate for the Chloe-Jackson style of mineralisation and were reported appropriately in accordance with the JORC Code 2012.
Chloe-Jackson Deposit JORC Mineral Resource – As at August 30th 2019
1Mineral Resources are reported above a 1.0% Zn cut-off grade
Chloe & Jackson – Mineral Resource/Exploration Upside
The Chloe & Jackson deposit has exploration potential both down dip in each deposit and also along strike between the two mineralised domains.
Railway Flat Project
Located within the Einasleigh region, some 3 km west of Einasleigh township, the Railway Flat deposit is one of the advanced projects of the region. It is a zinc/lead sulphide deposit that has had a substantial amount of exploration including drilling, completed over a period of 30 years. There are no reports of historical mining.
Railway Flat was discovered in the 1970s. In 1977, Railway Flat was targeted for more detailed exploration, due to its relative proximity to Einasleigh Copper Mine and Kaiser Bill. It was also considered to be under-explored due to extensive soil cover. A total of 16.5k m of gridding along a 10.5 km base line was completed over the prospect area and an auger drilling program was completed on a 500 m x 25 m grid. This initial drilling outlined an anomalous zone of lead and zinc over a 2 km strike length. Several costeans and percussion drill holes were also completed with encouraging results.
Exploration continued over the following years to the early 1980s, including further gridding, auger drilling, percussion and diamond drilling, a ground magnetic survey, a Pulse EM survey and Down-Hole Transient Electro-Magnetic (DHTEM) methods. A total of 32 percussion holes and five diamond holes defined an Inferred Mineral Resource reported, in accordance with the JORC Code 2004, as 500,000 tonnes at 4.2% Zn, 1.3% Pb, 25 g/t Ag and 0.3% Cu. CRA withdrew from the Joint Venture in 1983 and Otter pegged mining leases over the most prospective areas of the belt which included MDL92 over Railway Flat.
In the mid-1990s, BHP Exploration and Otter conducted minor exploration including soil sampling, ground magnetics and drilling.
Having taken control over the prospect area, Copper Strike completed two drilling campaigns during 2007 and 2008 for a total 37 drill holes, increasing the Inferred Mineral Resource, reported in accordance with the JORC Code 2004, to 0.94 Mt at 3.4% Zn, 0.9% Pb, 0.2% Cu and 17 g/t Ag.
Geology and Mineralisation
The Railway Flats area, was identified by CRA as a shallowly covered to sub-cropping lead-zinc anomalous zone extending along strike for 2 km. The mineralisation is hosted by meta-sedimentary biotite gneisses, close to the contact with underlying magnetic calc-silicates which are interpreted as the lowest unit of the Palaeoproterozoic Etheridge Group in the Einasleigh area. Pegmatites and amphibolites also occur within the biotite gneiss package. These rocks strike approximately NE and dip moderately to the SE.
Alteration is associated with mineralisation but is of limited extent. The alteration consists of semi-massive fine-grained garnet along with epidote-garnet-quartz, and silicification is associated with stringer mineralisation.
Base metal mineralisation consists of two sub-parallel sulphide lodes, the Hanging Wall Lode (“HW”) and the Footwall Lode (“FW”), with their stratigraphic separation varying between 10 m – 20 m. In places, the lenses coalesce to produce thick intersections of better grade material. The lodes strike NW-SE and dip about 45° to the SW. The HW Lode is a slightly thicker unit and appears to be more continuous and has a greater areal extent. The FW Lode appears to become narrower in the down dip direction and has a more obvious plunge of 45° to grid west.
The lodes can be reasonably continuous, and even where there are no percent grade intercepts, their position is marked by anomalous Pb-Zn. The FW Lode tends to disappear sporadically for some, as yet unknown, structural reason. It may be that there is a considerable boudinage affect associated with structural deformation.
The style of mineralisation is believed to be stratabound but includes at least two styles, namely veins/stringers and pyrrhotitic “durchbewegung” breccias i.e. sheared sulphides with plucked clasts of wall-rock. This style is, therefore, largely structurally controlled but quite variable in base metal mineralisation . The stringer zones occur in lenses of low-grade stringer-style mineralisation of pyrrhotite, sphalerite and minor galena typically in a silicified matrix. Base metal sulphides include sphalerite, galena with trace chalcopyrite in semi massive pyrrhotite lodes. There are minor amounts of pyrite. The semi-massive and massive sulphides, dominated by pyrrhotite, tend to obliterate the host rock texture.
Based on comparison with other deposits within CSD’s Einasleigh Project area, the mineralisation supports a model of early (approximately syn-sedimentary or diagenetic) emplacement of Pb-Zn sulphides into the sequence. There has been significant modification during subsequent metamorphic event/s. At one time, the mineral and host rock styles were thought to indicate similarities with the Broken Hill-type of mineralisation, however, this theory is no longer supported.
Railway Flat JORC (2004) Resource Estimation
The most recent Mineral Resource for Railway Flat was reported in accordance with the JORC Code 2004). The Mineral Resource estimate has not been updated to comply with the JORC Code 2012 on the basis that the information used for the estimate has not materially changed since it was last reported.
The Mineral Resource estimate is summarised below.
The Mineral Resources were estimated by Hellman and Schofield Pty Ltd in 2008.
The Mineral Resource was estimated using a total of 53 drill holes that were a combination of reverse circulation drilling and NQ2 sized diamond core.
The drill holes were geologically logged for key geological and mineralisation domains and either splits from 1 m sample lengths for the reverse circulation samples or half core sampled, typically in 1 m lengths, and samples were sent to the ALS Chemex laboratory in Townsville for assaying. The assaying method used for samples within the Townsville laboratory was 50 g fire assay with an Atomic Absorption Spectrum (AAS) finish, a split of each sample was also sent to the ALS Chemex laboratory in Brisbane for multi-element analysis using the ICPAES method.
Hellman and Schofield consultants estimated the Mineral Resources using ordinary kriging and no cutting of high-grade assay outliers was assessed as necessary. Density was estimated by inverse distance squared using a dataset of 720 discrete density samples. The Mineral Resource was reported using a cut-off grade of 2.0% Zn.
The sampling and assaying methods and the grade estimation method used were appropriate for the Einasleigh style of mineralisation.
Railway Flat Deposit Mineral Resource Estimate as at October 2008
1Mineral Resources are reported above a 2.0% Zn cut-off grade
Railway Flat – Resource/Exploration Upside
The Railway Flat deposit is open at depth and to the west of the currently defined hanging wall and footwall mineralization domains.
Railway Flat Deposit – Upside Potential
Kaiser Bill Project
The Kaiser Bill prospect is an undeveloped Iron Oxide Copper Gold (IOCG) deposit located about 8 km west of Einasleigh Township in north Queensland.
By 2016 the deposit had been tested by 157 drill holes totalling 23,498 m in length. Specific work included:
- Drilling of eleven holes in 2009 to more closely define and upgrade the Mineral Resource.
- Drilling of four holes to define extensions to the deeper, western part of the deposit.
- Revision of the Mineral Resource estimate (Golder Report, dated July 2010).
- Geotechnical drilling of seven holes.
- Downhole acoustic televiewer scanning surveys to assist in geotechnical assessment.
- Geotechnical assessment and report by Coffey Mining.
- Ongoing assessment and review of the siting of proposed infrastructure on the Kaiser Bill MLA.
After further drilling in 2017, Indicated and Inferred Mineral Resources at Kaiser Bill were reported in 2017 by Mining Associates in accordance with JORC Code 2012, at 0.5% Cu cut-off as 15.5 Mt at 0.93% Cu with minor silver. The Mineral Resource was updated to account for drilling completed in 2017 and 2018 and was reported by Mining Associates, in accordance with JORC Code 2012, at 0.5% Cu cut-off as 16.91 Mt at 0.83% Cu above 150 mRL.
The Kaiser Bill deposit is hosted within a sequence of quartz-feldspar-biotite metasedimentary gneiss overlain by a massive felsic leucogneiss with the copper mineralisation occurring as chalcopyrite within quartz-pyrite-pyrrhotite-magnetite disseminations, stringers and breccia-fill. It has a thick massive central zone, with a southerly dip and well-developed west-southwest plunge. The mineralisation envelope diverges from the leucogneiss-biotite gneiss contact.
The mineralisation occurs as chalcopyrite, associated with quartz-pyrite-pyrrhotite-magnetite as disseminations, stringers and breccia hosted by quartz-feldspar-biotite gneiss. Alteration forms a relatively broad zone up to 120m wide with magnetite and weak quartz-chlorite and lesser epidote with very minor actinolite. The main ore zone occurs within quartz-feldspar-biotite gneiss close to the contact with a massive, felsic gneiss that forms the hanging-wall.
Mineralisation occurs within a broad alteration zone that has been intersected in drilling over a distance of at least 1.4 km. The mineralisation has dimensions of up to 80 m in thickness, extending at least 400 m down dip and over a length of 1 km). The thickest core of the mineralisation plunges at between 10° and 30° WSW and is open down plunge. More recent CSD drilling in 2017 confirmed that the mineralisation remains open down plunge/dip.
Kaiser Bill Project – Deposit Long Section with Pit Optimisation Shell
Kaiser Bill Mineral Resource
The Kaiser Bill Mineral Resource estimate was reported in 2018 in accordance with the JORC Code 2012.
The Mineral Resource estimate for the Kaiser Bill Deposit is summarised below.
The Mineral Resources were estimated by Mining Associates Pty Ltd in 2018.
A total of 169 drill holes, a combination of reverse circulation drilling and NQ2 sized diamond core, were used for the estimate.
The drill holes were geologically logged for key geology and mineralisation domains and either splits from 1 m sample lengths for the reverse circulation samples or half core sampled, typically in 1 m lengths. Samples were sent to the ALS laboratory in Townsville for assaying. A small percentage of samples (4%) were assayed in the SGS laboratory in Townsville.
Mining Associates consultants estimated the Mineral Resources using ordinary kriging and a range of top cuts was applied to the assay data. Top cuts ranged from 2.46% to 3.37% for copper and 43 g/t to 43.2 g/t for silver. Density was estimated by using a regression formula as a strong correlation exists between density and Fe% grade within the deposit. A dataset totalling 2,230 density measurements was used to create the regression formula.
The sampling and assaying methods and the grade estimation method used were appropriate for the Kaiser Bill style of mineralisation.
Kaiser Bill Deposit Mineral Resource Estimate – As at October 2018
1Mineral Resources are reported above a 0.5% Cu cut-off grade
Kaiser Bill Resource/Exploration Upside
The Kaiser Bill deposit remains open at depth down plunge and represents the potential extension of the main mineralised domain.
Drilling completed within the deposit has shown potential for higher grade copper mineralisation to occur at depth within the down plunge orientation of the deposit. Potential also exists to define smaller additional lenses of copper mineralisation adjacent to the defined main zone.
Kaiser Bill Deposit – Down Plunge Upside Potential
Einasleigh Regional Exploration Projects
Regional Exploration Target Summary
Outside of the Kaiser Bill, Chloe-Jackson, Railway Flat and Einasleigh copper deposits, there exist numerous exploration targets that are hosted within similar geological and mineralisation settings. Anomalies have been defined via surface gossan exposures, soil sampling, geophysical surveys and shallow reconnaissance drilling.
The exploration potential of the Einasleigh area is assessed as high given that the historically defined deposits do not have large surface expressions. For example, the Kaiser Bill deposit shows very small gossanous outcrops over a deposit that extends approximately 1 km along strike and the Railway Flat deposit does not outcrop at all. Potential therefore exists for other outcropping and “blind” deposits to exist within the project area.
CSD has assessed exploration targets via their surface geochemical signatures and geological setting and ranked them to guide future exploration activities within the project area.
The primary exploration targets are shown below.
Einasleigh Regional Exploration Prospects
Einasleigh Regional Exploration Prospects