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Kaminak Reports Up to 85% Gold Recovery from Transitional Mineralization at Coffee Gold Project

by ahnationtalk on July 30, 2015546 Views

Vancouver, B.C. – Kaminak Gold Corporation (KAM: TSX-V) today announced results of the comprehensive metallurgical test work program conducted on transitional facies mineralization collected from the Coffee Gold Project, Yukon.  The metallurgical results from bottle rolls, column testing and extensive cyanide (CN) soluble assaying will be used to better define the different facies of mineralization in the updated 2015 resource block model, which will be included in the feasibility study (“FS”), currently underway and scheduled for completion in Q1, 2016.

In 2014, Kaminak undertook a preliminary economic assessment (“PEA”) at Coffee, which focused on oxide mineralization (mineralized zones containing in excess of 90% oxidized material) as there was little data available at that time to characterize gold recoveries from deeper transitional facies material.  Later in the year, Kaminak collected additional metallurgical samples from both upper transitional mineralization (defined as nominal 80% cyanide recoverable gold between 70% and 90% oxide) and middle transitional (defined as nominal 60% cyanide recoverable gold between 50% and 70% oxide) with the aim of potentially qualifying additional recoverable gold resources for inclusion in the FS.  A complete table of results from the 2014-2015 program is included below with highlights as follows:


  • Column leach test results for transitional material at the 0.5 inch and 2.0 inch crush sizes collected from the Latte, Supremo and Kona deposits yielded the following recoveries:
      • Latte upper transition core composite recovered 82.5% (2 tests)
      • Latte middle transition core composite recovered 58.5% (2 tests)
      • Supremo upper transition core composite recovered 84% (2 tests)
      • Kona upper transition core composite recovered 74% (2 tests)
  • Agglomeration was not required for any of the column tests and low reagent consumption was reported.
  • All of the column leach tests at the 0.5 inch size were performed at a temperature of 4 degrees Centigrade to simulate cold climate leaching.  Column leach test work was conducted by Kappes, Cassiday and Associates (“KCA”), industry leading experts in heap leach processing.

Supporting images associated with this metallurgical test work program may be viewed by clicking the following link:

Kaminak cautions that these new metallurgical recoveries should not be applied to the 2014 block model for the purposes of estimating a potential contribution of transitional ounces to the existing PEA mine plan, as the mineralized oxidization facies were defined differently in 2013 and 2014 and are not comparable.  Further, the final FS will incorporate a revised block model (based on infill drilling completed in 2014/2015) together with detailed geotechnical information, which was unavailable for the PEA.

Fred Lightner, Director of Mine Development to Kaminak stated:  “The most recent test results from the KCA testing program will provide the basis for a much better quantification of gold recoveries from transitional material of the Coffee deposits for inclusion in the FS.  When all of the revised block models for each deposit area have been completed and the final mine plan has been established, we will then have the basis for the determination of gold production for the FS.”

2014-2015 Coffee Gold Project Metallurgical Test Work Program
Results of the column leach tests conducted by KCA are detailed below in Table 1, 2 and 3. It should be noted that two different crush sizes were tested on the core composited transitional samples:  2 inch refers to a sample 100% passing 62.5 mm or approximately 80% passing 50 mm and 0.5 inch refers to a sample 100% passing 16 mm or approximately 80% passing 12.5 mm.

Table 1                                           Column Leach Test Results
Core Composites Transitional Samples (180 samples collected from 54 drill holes)

Column Sample Description
and Location
0 C
g/t Au
g/t Au
Latte Upper Transition 22 2.0 1.458 1.197 82% 81 0.79 1.49
Latte Upper Transition 4 0.5 1.928 1.597 83% 81 0.44 1.51
Latte Middle Transition 22 2.0 1.473 0.924 63% 81 0.76 1.52
Latte Middle Transition 4 0.5 1.061 0.578 54% 81 0.30 1.50
Supremo Upper Transition 22 2.0 1.041 0.890 85% 67 0.61 1.50
Supremo Upper Transition 4 0.5 0.932 0.753 81% 67 0.43 1.20
Kona Upper Transition 22 2.0 1.358 0.979 72% 81 0.76 1.53
Kona Upper Transition 4 0.5 1.351 1.022 76% 81 0.50 2.01

No percolation problems were reported in any of the column leach tests; therefore, the use of cement agglomeration was not required. All of the column leach tests at the 0.5 inch size were performed at a temperature of 4 degrees Centigrade to simulate cold climate leaching. The 2 inch crush size columns were too large to be contained in the refrigerator and were leached at ambient lab temperature (220 C). Previous work has shown only a minor (-1%) gold recovery difference between ambient and simulated cold climate leaching.

Comparative Bottle Roll Test Work
Results from bottle roll test work undertaken on splits of the same composites utilized for column leaching are detailed below in Table 2. By using a fine grind, recoveries were not substantially increased over the column leach tests, indicating that heap leaching is the preferred method of gold extraction over agitation leaching (given the lower capital and operating costs typically associated with heap leaching).


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