Craig Brown, Chief Executive Officer commented: “I am extremely pleased with the professionalism of the Company’s technical team in devising the structured approach to bag testing that has been developed.
Creswick is a unique project and the assessment of in-situ gold mineralisation requires bespoke project management and technical application.
I am delighted that our first metal detecting of bags has already highlighted metal content, which we expect is reflective of nugget gold mineralisation as samples from depth are unlikely to contain other detectable metals.
Our internal modelling suggests the Dimocks Main Shale is large enough to potentially host a multi-million ounce gold deposit at Creswick and therefore ECR are allocating resources to this project in a prioritised manner whilst continuing to develop our other Australian gold projects in parallel.”
ECR Minerals plc (LON:ECR), the precious metals exploration and development company, is pleased to provide an update in respect of the Company’s follow on gold nugget test programme at the Company’s Creswick Project in Victoria, Australia. The test programme has been designed by ECR, in conjunction with its advisers.
Readers are also advised to review the Company’s previous announcement dated 8 May 2019 which outlined the presence of a nuggetty gold system at Creswick, and this may be viewed through the following link:
- ECR’s technical team, in conjunction with advice from tendering laboratories, have devised a structured approach to systematically test zones in and around the 640 sample bags (each close to 30 kg) containing quartz collected from the recent reverse circulation drilling campaign at the Creswick Gold Project;
- An initial trial selection process will utilise a metal detector to prioritise bags with a metallic signal. This is anticipated to expedite the sample selection from the large number of bags to send for full testing;
- Metal detecting is now underway and a number of bags have tested positive for metal content and have been removed from site for “whole-of-bag” testing. A testing process is being finalised with a preferred laboratory;
- Full laboratory analysis will require multiple steps including sieving, detecting, gold particle analysis, gravity concentration and assaying to determine the size distribution and grade of the coarse and fine gold within the sample;
- ECR will communicate the results of the testing process within an initial update expected in the near term and further interim updates as the whole of bag testing process continues.
Within its previous exploration work and as announced by the Company on 8 May 2019 ECR hypothesised an extreme nuggetty distribution of gold based on observations and results, including capturing a small 0.27 g nugget in gravity tests conducted on a single sample bag. This means that gold is not evenly distributed in bags of drilling samples.
The Company previously assayed 2 kg samples from a 30 kg bag which is industry practice but too small a sample for extreme nuggetty distribution. There was a significant likelihood that coarse gold could be excluded from the sample.
This meant that assays samples could be understated for gold and this was demonstrated in one bag test where the assay from a 2 kg sample reported gold of 1.88g/t whereas the 30kg whole of bag sample test showed the bag actually contained a substantially higher 11.8g/t. Alternatively, a single assayed nugget will overstate the average from a 2 kg sample.
Based on the size of the previously recovered 0.27 g nugget, an ideal sample size could be approximately 5,000 kg. A 30 kg bag is 0.6% of this size and not large enough to be considered a representative sample, but a fifteen-fold improvement on 2 kg samples. There remains a high chance the full bag tests will not capture the nuggets. However, the greater number of full bag tests will increase the likelihood of including nuggets.
A visual representation of the DMS and the Company’s mapping, which demonstrates the potential link from the alluvial source with the DMS, is provided through following links to the ECR Minerals website:
“Whole-of-bag” testing methodology
Following discussions with its technical team ECR concluded it should move into a process of “whole-of-bag” testing to determine the full extent of the gold within the reverse circulation samples. This is a sizeable exercise. Of the 1687 m drilled, 640 bags of close to 30 kg each contain quartz and these bags plus the surrounding bags will be tested.
In order to achieve the above objectives the Company’s technical team, in association with external consultants including laboratories capable of undertaking the whole of bag sample work, have considered numerous approaches to the testing process. This involved visits by ECR to the laboratories and consideration of various testing pathways and associated record keeping and process validation.
Analysis will test the primary hypothesis that gold is coarse but a program is being designed to additionally check for fine gold within the bags to assess the size distribution of the particles.
After due consideration of all factors and a range of practical tests, the Company is finalising a testing procedure at a suitable laboratory which is likely to follow the steps below:
1. Initial metal detector scanning of bags to prioritise bags to send to the lab for full testing. The Company considers that nuggets large enough to significantly impact the nugget effect will be able to be located with a metal detector. This will save the company the cost of testing all bags. A series of bags with no signal will be collected for analysis of the finer gold fraction, especially if the main set of bags show a significant fine gold component;
2. Secure transfer of bags testing positive for metal content to the laboratory for whole of bag testing;
3. Under laboratory conditions sensitive metal detector scanning of the coarse sieved (>0.85 mm) fraction of the bags is undertaken and the source of the signal removed, examined, logged, photographed and weighed. The entire coarse sample will then be assayed to calculate the total coarse gold from the bag;
4. The fine sieved fraction (<0.85 mm) will be gravity concentrated and this concentrate plus all of tails assayed for gravity recoverable and total gold. Following this step, all of the contents of the original bag would have been assayed;
5. The total gold content for each size fraction of each whole tested bag is calculated.
Initial findings from first batch of bags tested
After establishing the above testing protocol, the Company’s technical team have commenced initial metal detection of the bags as outlined by step one above
During the first phase of metal detection work a number of bags have generated a positive signal from the metal detector. These bags have been secured for transport to the laboratory for whole of bag testing under laboratory conditions.
Further metal detection tests are continuing and additional bags testing positive for metal will be securely transferred to the laboratory for whole of bag examination.
Whilst it is not certain that the tested bags contain gold, or as to what grade of mineralisation exists, and whether this is elevated grade against previous bag assay samples, the Company’s technical team consider the number of bags responding to date is very positive and the Company looks forward to receiving the “whole-of-bag” gold data from the early bags selected for laboratory analysis.
COMPETENT PERSON STATEMENT
The information in this announcement that relates to Exploration Results is based on information compiled by Dr Rodney Boucher of Linex Pty Ltd. Linex Pty Ltd provides geological services to Mercator Gold Australia Pty Ltd, including the services of Dr Boucher, who has a PhD in geology, is a Member and RPGeo of the Australian Institute of Geoscientists and is a Member of the Australasian Institute of Mining and Metallurgy. Dr Boucher has sufficient experience that is relevant to the style of mineralisation and type of deposit under consideration and to the activity being undertaken 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’. Dr Boucher consents to the inclusion in the announcement of the material based on his information in the form and context in which it appears.
MARKET ABUSE REGULATIONS (EU) No. 596/2014
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 (MAR). Upon the publication of this announcement via Regulatory Information Service (RIS), this inside information is now considered to be in the public domain.
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