FIRST GOLD RECOVERED FROM METALLURGICAL SAMPLES
HIGH GRADE ORE ALLOWS FOR NON CHEMICAL RECOVERY METHODS
New Talisman Gold Mines Limited (“NTL”), today announces the first recovery of gold from its Talisman gold mine as part of its metallurgical sampling as a precursor to bulk sampling ramp up and test work. This was recovered utilising state of the art non chemical extraction methods.
Talisman is an important gold resource for New Zealand and was in the past a prolific gold producer and employer having produced 1 m oz of gold historically, in a gold region which has produced over 8m oz of gold.
GOLD RECOVERED FROM METALLURGICAL SAMPLING
Metallurgical test work investigated a suitable floatation and gravity recovery method of extracting gold from ore samples. The company tested 146 kg of very finely ground ore and has produced approximately 3 ounces of gold and silver. Further concentrates will be used for more test work to evaluate the most effective recovery rates.
Hand selected samples were collected from the Talisman stockpile in bags of approximately 8kg each. Samples were classified into rock types and an example of each type retained for identification purposes. Samples were then processed at the SGS Waihi laboratory being crushed and pulverised before passing through a 50 micron screen (approximately the same grain size as cement). The pulverised product was then thoroughly mixed and a representative sample taken for assay purposes.
Lower grade samples were discarded as the equipment is not sensitive enough to record micro gram recovery levels. The assay results of the samples selected for processing are tabulated below and a photographic record of examples of those samples is shown in the table overleaf.
Grades included in test sampling
This testwork relied heavily on wet gravity separation to remove the clay and other light minerals from the heavier electrum and sulphide minerals. It was found to be important to pass as clean a concentrate as possible through the final concentrator as the equipment relies on recirculating water and excess clay was kept in suspension causing cloudy water to be passed back through the separator bowl.
In order to float out the clay approximately 2.5kg at a time of the sample was added to a bucket along with 3 litres of water and a small amount of surfactant to break surface tension and prevent fine gold particles being washed away. The mixture was stirred thoroughly to move the clay into suspension and then allowed to settle for a minute. Approximately 2/3rd of the liquid was then decanted and the process repeated until rapid settling was attained. It was found that, on average and dependant on the grade of the sample, a 7kg sample could be concentrated to approximately 160g of material which was then passed through the final concentrator.
Matthew Hill, Executive Director, said “whilst this is a small amount of gold, in the larger scheme of things it is key to demonstrating our fuller understanding of the effectiveness of our extraction method options. Without unnecessary expenditure and use of chemicals, we have identified a number of manufacturers to scale up the treatment options allowing for concentration and extraction, prior to any toll treatment driving early revenues to the company.”
ABOVE: THE GOLD LAB UTILISING GRAVITY AND FLOTATION – resulting gold recovered
“These are the first ounces recovered from the Talisman ore since New Talisman owned the permit and show the huge strides the company has made its final steps toward bulk sampling for which final approvals are underway. We have found nothing but support from shareholders and the wider community.” Following initial test work we expect to be able to recover up to 30 oz gold per month using existing samples, while initiating precursor work toward bulk sampling.