Published 21 September 2018
Copperstone Resources AB (“Copperstone” or “the Company”) is pleased to announce significant copper assay results from drillhole COS18364 in the Granliden Hill area.
103m of semi-continuous chalcopyrite mineralisation intercepted from 315-418m returning 0.42% Cu and 3.24g/t Ag and containing an 11m zone from 343-354m returning 2.62% Cu, 17.5g/t Ag and 0.2g/t Au.
Drill hole COS18364
COS18364 was collared east of Granliden Hill approximately 200m north of COS18360 and was drilled due west at -60 degrees dip to a length of 663.80m. From 35.9m the drill hole intercepted a thick package of mafic amygdaloidal lava overlying banded siltstone / arenite (with pyrrhotite) and underlying quartz porphyritic rhyolite. Within the lower part of the drillhole there are also intercalated zones of micro-diorite, minor hydrothermal breccia and younger post-mineral intermediate dykes. Mineralisation consists exclusively of chalcopyrite with subordinate pyrrhotite, pyrite, arsenopyrite and minor bornite. Mineralisation styles are either irregular stockwork-like veining over continuous zones, or discreet narrow veins. A single thick intercept of continuous chalcopyrite was intercepted from 347-348.15m (1.15m) and returned 16.15% Cu, >100g/t Ag and 0.58g/t Au. This intercept is contained in a high grade zone from 343-354m (11m) grading 2.62% Cu, 17.46g/t Ag and 0.2g/t Au. In some places veins are associated with micro-brecciation textures, associated with quartz and in general with little to no visual wall-rock alteration effect.
Note that all lengths quoted above are drilled intercept lengths only and the true width of mineralisation is not known. Composite grades are weighted averages with no capping applied. Choice of composite zone is based purely on the visual recognition of mineralisation pattern.
Ongoing laboratory testing
At the moment laboratory testing is still ongoing for drill holes COS18360, COS18362 and COS18363. A further 11 drill holes from the NANR campaign (2004-2007) and the earlier Copperstone campaign 2015 have also been sampled. The main objective of the latter is to close the gaps within the sample string so that composite grades can be determined.
Chalcopyrite mineralisation found in COS18364 is similar in style and patterns to that found in all drill holes from the Granliden Hill area. In many drill holes, the style of mineralisation is composed of thicker high grade (>1% Cu) veins, surrounded by areas of narrower veinlets forming broader zones of low grade (<1% Cu) mineralisation. In some instances high grade veins are more isolated, or intercepts of lower grade envelopes do not intercept any high grade veins. This pattern is repeatable and gives an insight into the macro patterns along the length of the mineralised zone. At this stage the true widths and lengths of individual zones and veins are not known but it is clear that these features are widely distributed across the Granliden Hill area with an estimated trend ranging from north-south to northeast-southwest.
Chalcopyrite mineralisation does appear to cross-cut the host geology package and suggests strong structural control. In the 2018 campaign three drill holes have also found a felsic granitoid rock (stock) that also appears to have a north-east trend. This southern igneous body could potentially be syn-mineral and possibly causative to the mineralisation. The bias of individual intercepts and widths of uncapped weighted average composited grade are largely dependent on the drillhole azimuth and dip relative to the overall trend of the mineralised zone.
Core Assays and Quality Assurance / Quality Control
All drill core boxes were delivered by the Drill Contractor to the secure Copperstone Site Office 1km from the drill site. Before transport to Malå, preliminary inspection and logging is carried out by Copperstone personnel. Core is then logged in detail at the Copperstone Facility in Malå before zones for sampling are selected. Once sample zones are identified and ticketed core boxes are then collected for laboratory analysis.
Sample preparation including half-core sawing, crushing, splitting and pulverizing has been carried out at ALS Minerals Laboratories, an accredited laboratory based in Malå. Prepared 50g aliquot pulps are then couriered to their Analytical Laboratory in Ireland. Sample analysis is then 4-acid digestion followed by ICP finish (ME-MS61) for 49 elements, including Ag, Cu and Zn. All samples with greater than 10,000ppm (1%) Cu and / or Zn are re-run with 4-acid digestion and then ICP-AES finish (Cu-OG62 and Zn-OG62) with results reported in percentage. Gold values are determined with a 30g fire assay fusion with AAS finish (Au-AA23).
In total 73 samples each with a drill length of 2.0m were submitted for assay from COS18364. This represents approximately 23% of the NQ core in this drillhole. The certificated copper-gold standard reference samples used are OREAS 501C and OREAS 502C, as well as blanks and duplicate samples inserted at regular intervals in the sampling sequence in order to maintain Quality Control (accuracy and precision). A total of 12 qaqc samples (4 blanks, 4 standards and 4 duplicates) were submitted at a 1:20 frequency. All qaqc results reported by ALS are within acceptable limits for the two batches submitted for COS18364.
“This is our best intercept since we began exploration in the Granliden area. In fact this drillhole is top in both the single assay result and cumulative length of copper mineralisation categories, and that is very exciting. Again we have found another significant long intercept of copper mineralisation, and this has strengthened the potential for extending the area of known mineralisation significantly beyond the historical limits of Granliden Hill. It’s now obvious that the system is large and spread out across at least 1.0km north-south up to a few old holes north of Granliden Hill. We can’t say anything now about the possibility for an economic outcome but I’m very excited about the possibilities. Nowhere else in Sweden is there such a possibility I believe. Now that drilling is complete we are working on the modelling of this data and building a picture of the potential mineral resources. This work is changing the future of this company” comments Chris McKnight CEO of Copperstone.
For further information, please contact Chris McKnight (CEO) at +46(0)580-88890, or email@example.com or refer to Copperstone webpage: www.copperstone.se.
This press release contains insider information which Copperstone Resources AB (publ) is obliged to publish according to the EU market abuse regulation (MAR). The information was delivered by the above mentioned contact for publishing 21st September 2018 at 0830 CET.
Copperstone Resources AB is a public company trading as COPP B on NASDAQ First North (Stockholm). The Certified Adviser is Augment Partners AB. The Company is focused on base and precious metal exploration in the vicinity of the internationally-recognized mining region of the Skellefte-field in northern Sweden. The Copperstone project is situated on four contiguous exploration permits in Norrbotten County (Sandberget 100 (8074ha), Sandberget 200 (19ha), Sandberget 300 (19ha) and Svartliden 1001 (444ha). In addition the Company owns one exploitation concession within the same area, namely Svartliden K no. 1 (36ha) and an approved application for Eva k no. 1 (34ha) subject to an objection. The Company also owns the Tvistbogruvan K no. 1 (11ha) exploitation concession and the Såggården No.1 (199ha) exploration permit in the Bergslagen mining region of central Sweden. Quoted surface areas are approximate to the nearest hectare. All exploration permits and exploitation concessions are 100% owned, either directly or through a subsidiary.
All information in this press release has been reviewed and approved for publication by the appointed independent Qualified Person Mr Thomas Lindholm (M.Sc. Mining Engineering) of Geovista AB. Mr Lindholm is a registered Member of the Fennoscandian Review Board and has in excess of 35 years' experience in mineral exploration in Sweden and abroad and is a Qualified Person under the Nasdaq First North Stockholm rules. Mr Lindholm consents to the inclusion of the information in the form and context in which it appears.
News releases, presentations and public commentary made by the Company, and its Officers, may contain certain statements and expressions of belief, expectation or opinion which are forward-looking statements, and which relate, inter alia, to interpretations of exploration results to date and the Company's proposed strategy, plans and objectives or to the expectations or intentions of the Company's Directors. Such forward-looking and interpretative statements involve known and unknown risks, uncertainties and other important factors beyond the control of the Company that could cause the actual performance or achievements of the Company to be materially different from such interpretations and forward-looking statements. Accordingly, the reader should not rely on any interpretations or forward-looking statements; and save as required by the exchange rules of NASDAQ First North (Stockholm) for listed companies or by applicable laws, the Company does not accept any obligation to disseminate any updates or revisions to such interpretations or forward-looking statements. The Company may re-interpret results to date as the status of its assets and projects changes with time expenditure, metals prices and other affecting circumstances.