newsPlexmar tests Bolsa tailings for 83-per-cent recovery
Plexmar Resources Inc (TSX-V:PLE)
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Last Close 7/18/2005 $0.07
Tuesday July 19 2005 - News Release
Mr. Guy Bedard reports
PLEXMAR RESOURCES INC.: METALLURGICAL RESULTS
Plexmar Resources Inc. has received the first results from metallurgical tests carried out on gold- and silver-bearing material from its Bolsa del Diablo property located in Northern Peru.
Exploratory tests were carried out to evaluate the behaviour of this ore to cyanidation and its possible operating parameters, like gold and silver recoveries, cyanide and lime consumption, and time of residence.
Tests were performed at Cimm Peru Inc., a lab with international certification.
A 70-kilogram sample of tailings from an amalgam of oxidized gold ore coming from the Bolsa del Diablo property was tested. The material was taken from different pits after local miners extracted gold using "quimbaletes" to crush the ore and amalgamating gold with mercury. The head grade was 37.4 grams per tonne Au, 60 g/t Ag, 273 parts per million of Hg and 0.3 per cent As.
Currently, local miners are extracting ore grading as high as 150 grams of gold par latta (33 lattas equals one ton), so 4,950 g/t or 149 ounces of gold per ton.
The cyanidation tests of soluble gold and CIL were carried out with regrinding to 93 per cent minus-200 mesh (74 microns), approximately 100 per cent minus-100 mesh to a pH of 10.5 and with an average of 1,500 parts per million of cyanide in pulp of 30 per cent of solids; for 60 hours of agitation.
Recommendations and comments
It is possible to recover more than the 83 per cent of the gold and 31.6 per cent of the silver with direct cyanidation, CIL, with an agitation time of 60 hours from an amalgam of tailings from Bolsa del Diablo. Better gold and silver recoveries could be obtained by increasing the agitation time and the degree of grinding. It is recommended to continue the tests to tune up these parameters in order to reach a minimum 90-per-cent recovery for gold.
Despite the arsenic content, the cyanide consumption is relatively low: less than two kilograms per tonne of ore, the lime consumption (85 per cent useful lime) is also low, less than two kilograms per tonne of ore.
It is recommended to carry out a petrography study to determine the minerals associated with the gold and silver. This would give more information to improve the processing and the recovery of values.
The CIL or CIP process, with coal activated in pulp, would be the most adequate, since a very good kinetic extraction is observed the first 24 hours, diminishing drastically in the following hours presenting a prerubbing effect.
It is finally recommended to complete metallurgical tests with representative samples of fresh ore.
Plexmar's management is quite happy with these results as it indicates that the ore could be processed in a very cost-efficient way. Tests will be carried out with fresh rock as soon as possible. It is Plexmar's intent to install a processing plant in the area to quickly generate a cash flow in order to finance its exploration program. Please refer to news as reported in Stockwatch March 29, 2005.
M. Guy Bedard acted as the qualified person (as defined by the National Instrument norm 43-101).