Last checked at 7 Sep 2017 07:00
7 September 2017
GOLDSTONE RESOURCES LIMITED
("GoldStone" or the "Company")
Operational Update - Akrokerri Deep Trenches and Licences
GoldStone Resources Limited (AIM: GRL) announces the results of a deep trenching programme, completed as the first step of the pit definition programme announced on 17 July 2017, on the Akrokerri Licence in Ghana. The trenching was undertaken to define the extent of the mineralisation in the near-surface oxide zone of the known deposit and augment the findings from the continued review by the Company of the historical database for the Homase and Akrokerri licences.
The Company dug four trenches (Figure 1), two in each of the proposed pits, within the Southern part of the 2012 JORC Code compliant resource ("Current Resource"). The trenches, located on the Southern part of the Current Resource and along strike from the old Homase pit, were identified as having a high potential for an initial open pit for heap-leach production within the oxide zone. The trenches were dug to a depth of 7 metres and channel samples were taken near the bottom of each trench in 1 metre consolidated intervals.
Figure 1. Location of trenching within the Proposed Pit Outlines in the Akrokerri Licence
http://www.rns-pdf.londonstockexchange.com/rns/0398Q_1-2017-9-6.pdf
The trenches showed economic intersections of up to 14 metres true width with grades of up to 4.5 g/t of gold (see Table 1). Both widths and grades shown in the trenches were above the Company's expectation, exceeding the intersections of nearby drill holes (see Figure 1) by approximately 20 per cent. This indicates the potential for increased gold content in the upper oxide zone. The trenching also indicated that the zones have a free digging potential, which would reduce production costs considerably if the material is shown to be consistent.
Further trenching is now being set out to assess the extent of the mineralised zone within the Akrokerri Licence and the Company is currently conducting a pit definition reverse circulation (RC) drilling programme within the proposed pits.
The geology within the licences is typical for the Obuasi area. The mineralisation is contained within a highly-sheared suite of meta-greywackes and partly graphitic shales. A series of sub-parallel quartz veinlets is the main host of pyrite and minor arseno-pyrite. The gold mineralisation at Akrokerri is associated with both the swarms of quartz veinlets (pyrite/ arseno-pyrite/ free gold) and the disseminated sulphides in the shales and greywackes. The degree of contribution to the total gold content will vary on the strike and at depth and this will be determined during production.
The review of historical data has shown that the Homase pit, mined by Ashanti Goldfields ("AGF") between 2002 and 2003, produced 52,452 oz gold, which was significantly in excess of AGF's original estimate of 35,799 oz gold, reported in AGF's Homase Pit Mining Reconciliation June 2002-03. According to AGF's mining reconciliation figures, there was a significant increase in tonnage and minor increases in grade and density compared to the original estimates. The differences are between the ore reserve model (based on pre-production drilling) and the grade control model (based on more closely spaced drilling during production).
One of the features that resulted in the higher recovery of gold from the Homase pit was the higher than anticipated widths in the upper zones of the mineralisation, which caused a mushroom effect, i.e. near-surface gold mobilisation and re-deposition.
AGF also reported pinching and swelling within the mineralised structure. This is a consistent feature throughout the Homase/Obuasi shear system. Ore shoots at the nearby Obuasi mine are characterised by tight en-echelon lenses. If these are repeated within the proposed pits on Akrokerri, there is potential for increased gold content to continue at depth.
Table 1: Trench Assays
Proposed Akrokerri Pit - 1 | Proposed Akrokerri Pit - 2 | ||||||
Trench number | Sample ID | Au g/t | Trench number | Sample ID | Au g/t | ||
Trench 2 | Q1018 | 0.08 | Trench 1 | Q1002 | 0.55 | ||
Total length of Trench 2 - 17 metres | Q1019 | 0.08 | Total length of Trench 1 - 15 metres | Q1003 | 1.51 | ||
Q1020 | 0.08 | Q1004 | 0.62 | ||||
Q1021 | 0.08 | Q1005 | 0.73 | ||||
Q1022 | 0.05 | Q1006 | 1.08 | ||||
Q1023 | 0.07 | Q1007 | 0.61 | ||||
Q1024 | 0.03 | Q1008 | 0.67 | ||||
Q1025 | 0.04 | Q1009 | 0.43 | ||||
Q1026 | 0.03 | Q1010 | 3.18 | ||||
Q1027 | 0.06 | Q1011 | 1.75 | ||||
Q1028 | 0.08 | Q1012 | 3.68 | ||||
Q1029 | 0.03 | Q1013 | 2.11 | ||||
Q1030 | 0.05 | Q1014 | 2.58 | ||||
Q1031 | 0.15 | Q1015 | 1.36 | ||||
Q1032 | 0.30 | Q1016 | 0.81 | ||||
Q1033 | 1.23 | ||||||
Q1034 | 2.81 | Trench 4 | Q1047 | 0.03 | |||
Total length of Trench 4 - 17 metres | Q1048 | 0.07 | |||||
Trench 3 | Q1036 | 2.20 | Q1049 | 0.03 | |||
Total length of Trench 3 - 10 metres | Q1037 | 3.57 | Q1050 | 0.08 | |||
Q1038 | 3.16 | Q1051 | 0.06 | ||||
Q1039 | 4.51 | Q1052 | 0.06 | ||||
Q1040 | 3.72 | Q1053 | 0.12 | ||||
Q1041 | 1.05 | Q1054 | 0.12 | ||||
Q1042 | 1.17 | Q1055 | 0.25 | ||||
Q1043 | 0.78 | Q1056 | 0.94 | ||||
Q1044 | 1.03 | Q1057 | 1.06 | ||||
Q1045 | 1.53 | Q1058 | 0.70 | ||||
Q1059 | 1.36 | ||||||
Q1060 | 1.78 | ||||||
Q1061 | 0.19 | ||||||
Q1062 | 0.23 | ||||||
Q1063 | 0.13 | ||||||
Sampling, assaying and QA/QC
GoldStone's sampling and other geological activities conforms to industry-wide good practice. The Company maintains Quality Assurance and Quality Control on all analytical work via the use of certified reference materials, field duplicates and blank samples in addition to monitoring of internal laboratory check-analyses. Chain of custody is observed for all samples. Determination of gold, by fire assay of 25g sub-samples and atomic absorption finish, was undertaken by ALS Minerals Limited in Kumasi, Ghana.
Bulk samples from the trenches have also been sent to the University of Mines and Technology at Tarkwa, Ghana for metallurgical testing, under the supervision of Prof. Amanwah, the Dean of the Faculty of Mineral Resource Technology and Ghana's leading expert in the metallurgy of the Ashanti shear system. The result of the metallurgical testing will be announced once received.
Licence Update
The Company continues to review its portfolio and is in the process of renewing its licences in both Senegal and Ghana. With regards to Gabon, the Company is considering its options which will likely result in the disposal or relinquishment of the licences.
In respect to Ghana, all requisite documents have been submitted to the Ghanaian Minerals Commission for both Akrokerri (100 per cent. interest) and Homase (90 per cent. economic interest) and the Company has received confirmation that the licences are awaiting signature from the Minister of Mines.
The current drilling and trenching will facilitate in determining the potential pit design for the proposed Akrokerri pits and will provide the necessary platform for proceeding with an application to the Government of Ghana for a mining permit, following the extension of the licences.
For further information, please contact:
GoldStone Resources Limited | |
Emma Priestley / Neil Gardyne | Tel: +44 (0)7867 785177 / +27 (0)82 490 4427 |
Strand Hanson Limited | |
Richard Tulloch / James Bellman | Tel: +44 (0)20 7409 3494 |
SI Capital Limited | |
Nick Emerson / Andy Thacker | Tel: +44 (0)1483 413 500 |
Information in this announcement has been complied and reviewed by Klaus Kappenschneider, an independent geologist with 30 years experience in gold mining, exploration and resource estimation. Klaus is a member of the Association of Professional Geoscientist of Ontario (APGO), is a Competent Person (JORC, SAMREC, PEMREC) and a Qualified Person (NI 43- 101) and accordingly, is a qualified person as required under the AIM Rules.
The information contained within this announcement is deemed by the Company to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014.
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About GoldStone Resources Limited
GoldStone Resources Limited (AIM: GRL) is an AIM quoted exploration company with projects in Ghana, Senegal, and Gabon that range from grassroots to advanced exploration.
The Company is focused on developing the Homase-Akrokerri project in south-western Ghana, which hosts an existing 602,000 oz gold JORC Code compliant resource at an average grade of 1.77g/t, along strike from the Obuasi Gold Mine, one of the World's major gold mines with a total historical and current resource in excess of 70 million ounces of gold. It is the Company's intention to build a portfolio of high-quality gold projects in Ghana, with a particular focus on the highly prospective Ashanti Gold Belt.