Published 20th December 2018
Copperstone Resources AB (“Copperstone” or “the Company”) is pleased to announce that an Exploration Target potential of 150-210 million tonnes at a grade of 0.25-0.45% copper has been estimated by Micon International Co LTD (UK) (“Micon”) for the Granliden area of the project. This potential is in line with recent guidance and is based on an independent analysis of exploration drilling results predominantly from the drill campaign carried out by the Company in 2018.
In addition, the Company has also received a PERC 2017 compliant Mineral Resource Statement from Micon for the shallow copper mineralisation at both Granliden Hill and Svartliden. In total 26 million tonnes of Inferred Mineral Resource at a grade of approximately 0.43% copper has been defined, with reasonable prospects for eventual economic extraction at stated modeling factors.
The Granliden area of the project has been explored in 2018 with ten (10) NQ2 drillholes (total 7,615m). Drillholes were originally planned to interrogate new geophysical anomalies derived from Ground Magnetic and NSAMT field surveys carried out in 2017, and to build a clearer picture of the geological model and style of copper mineralisation. Significant assay results received during the period January 2018 until August 2018 have already been announced by the Company. Two drill holes (COS18359 and COS18364) both returned significant copper grades over wide intervals demonstrating that mineralisation is present at depth well under and to the east of Granliden Hill. Other drill holes in this campaign have also found copper mineralisation and the discovery of previously unknown granitic intrusives that may be related to the mineralisation event(s). These encouraging results have led to the possibility to now update the Exploration Target potential of the property.
In 2014 and before Copperstone had drilled any boreholes on the property, the Company indicated that an Exploration Target of 60-100 million tonnes at grades of approximately 1% copper may exist over the entire property. In order to consolidate all individual historical and new drill hole results in combination with an improved geological understanding, and to illustrate the significant discovery potential in Granliden area, the Company requested an independent assessment of the Exploration Target potential by Micon.
Wireframes of copper mineralisation in the Granliden area were constructed in 3D space using all drillhole results in that area. Excluding any mineral resources there is an estimated potential of 150-210 million tonnes of mineralisation at grades of 0.25-0.45% copper. Mineralisation is open in all directions. At present the spacing of drill holes outside of the mineral resource wireframes is too wide to generate any further code-compliant mineral resources. There is also no guarantee that further exploration drilling will define any further mineral resources within or beyond the current Exploration Target potential. However the Company is confident that further exploration is warranted to explore this potential.
In April 2016 Copperstone announced a JORC-compliant Inferred Mineral Resource of 5.4 million tonnes at an approximate grade of 1% copper for Granliden Hill and Granliden South. This estimate was provided by Geovista AB and was based on six (6) drillholes completed by the Company back then in addition to the historical drilling in those areas. Since then the Company has carried out further geological logging and infill sampling of historic drill cores, and down-hole Optical Televiewer probing in available drillholes to generate structural / trend data. From a review of all the new exploration data an improved estimation of copper mineralisation resources has now been carried out by Micon.
To create wireframes for mineral resource estimation, a cut-off of 0.135% copper, a capping of 3.69% copper and a maximum internal waste intercept of <10m was applied by Micon. In situ density is based on analysis of sulphur values in relation to laboratory density results generated historically and confirmed recently through check measurements by Copperstone. Block modelling was carried out using Inverse Distance Weighted to Power 3 (IDW3) estimation technique. Details of modelling parameters used by Micon are contained in their attached report.
To comply with rules for declaration of Mineral Resources as set out by the PERC code (2017) it is necessary to demonstrate that Inferred Resources have reasonable prospects for economic extraction using declared mining criteria. Whittle modelling was used by Micon to generate pit-optimized Inferred Resources at a mining cut-off of 0.1% copper at a metal price of 6,200USD / tonne. All pit optimization parameters and other factors are described in the Micon report attached.
Results of the Inferred Mineral Resource estimation by Micon are as follows:
Granliden: 16.92mt at 0.44% copper and 3.65 g/t silver
Svartliden: 9.43mt at 0.42% copper, 9.76 g/t silver, 0.12 g/t gold and 0.34% zinc
In total the shallow open pit Inferred Mineral Resources for the property has increased significantly to approximately 26mt with an average grade of approximately 0.43% copper and 5.90 g/t silver. This resource estimate is in addition to the 150-210mt Exploration Target now declared for the Granliden area.
The 9.4mt Inferred Mineral Resource at Svartliden is the first publication for this copper-zinc mineralisation zone. All mineralisation found thus far is contained within or close to the pit-optimised Inferred Mineral Resource wireframes. There is a low resistivity anomaly coincident with a magnetic anomaly right under this resource. Deeper exploration drilling is required to test out the cause of these geophysical anomalies and search for any further resource potential below. However there can be no guarantee that further drilling will locate any additional mineral resources at Svartliden.
All details for estimation of the Exploration Target and Mineral Resources can be found in the attached report from Micon.
“We have worked hard and with great belief. Today this is a great outcome for our project. I have seen down the years of my work that a large scale complex hydrothermal system exists here. Mineralisation is extensive, zoned and related to structurally controlled intrusives I believe. We have used the term porphyry-style to encompass our views and lay a foundation for exploration methodology and scale in the future. This year our first large drill campaign of 10 deep drill holes on the property has shown many new geological aspects, and tested out a few ideas. We found good mineralisation and established Copperstone as one of the main exploration companies based and operating in Sweden. This we are proud of and this effort has set the scene for future success. I have no doubt that we are on the right path, and with further drilling this massive potential can be realised for Copperstone.
I’m thrilled that our new estimate of the 150-210mt exploration target potential at Granliden alone has out-performed our first pre-drill estimates for the property. Right now further drillholes are required to test this massive target in the Granliden hill area. Here onwards the new wireframes can be a guide to value-creation through well-placed drill holes. Besides expanding the net of exploration drill holes beyond the wireframes, building of a gridded network of drill holes spaced close enough is key to growing and improving the resources of this property. This approach will bring great rewards I’m sure. Naturally I believe that subsequent resource estimates will grow in size and confidence, and in time the Company can look forward to those returns. Coppertone is a unique and exciting opportunity, and this has been a pleasure to develop thus far.” says CEO Chris McKnight.
For further information, please contact Chris McKnight (CEO) at +46(0)580-88890, or firstname.lastname@example.org 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 20th December 2018 at 19:50 CET.
Copperstone 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. In this area Copperstone owns two exploitation concessions, namely Svartliden k no. 1 (36ha), Eva k no. 1 (34ha) and two nearby exploration permits, namely Sandberget 200 (19ha) and Sandberget 300 (19ha). The Company has also recently applied for two new exploration permits, namely Sandberget 400 (535ha) and Sandberget 500 (7641ha) to form a contiguous block with existing titles. The project is based on 273 drillholes with an approximate total of 46,350m.
In addition 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 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 Association for Metals and Mining Professionals, FAMMP, 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.