The 2011 technical report details metallurgical testwork completed on the COSE project, including gravity concentration and cyanide leaching studies.
Report context
This 20 August 2011 technical report was prepared for Patagonia Gold S.A. and documents the metallurgical testwork program completed by SGS Minerals Services in Santiago, Chile. The report included assays, cyanide leaching bottle tests, and gravity separation tests performed on samples from the COSE project.
Processing route
Sample Preparation and Composition
A total of 70 samples were received and composited into 25 samples at Patagonia Gold’s request. The 25 composite samples and metallurgical tests were summarized in Table 17-1 of the report. SGS in Santiago is ISO-9000 certified.
Screen Fire Assays
A total of 16 coarse residues (95 percent less than 10# ASTM) from composite, high, and mid-grade intervals were analyzed via the screen fire assay technique. This technique determined the size and distribution character of gold mineralization. The technique was designed to concentrate potentially larger gold particles in the coarse fraction sample, given the tendency for gold grains to flatten during grinding. The method enabled semi-quantitative analysis on the potential presence and effects of coarse gold on sample analysis reproducibility of relatively small (50 gram) sample sizes.
Sample preparation involved first milling the coarse reject to 95 percent less than 200# ASTM. The undersize was sieved, weighed, and split into three subsamples, each subsequently fire assayed. The oversize was weighed and subsequently fire assayed, with values over 10 g/t Au determined using a gravimetric finish.
Gravitational Concentration Testing
Three composites weighing between 3.5 to 5 kg were submitted for gravity concentration tests. The samples were milled in a roll crusher to 100 percent less than 10# ASTM (2mm). For each sample, two representative 500 gram sub-samples were obtained using a Knelson concentrator. One sample was retained as a reference sample, and the other was further pulverized to 100 percent below 150# ASTM and analyzed by fire assay to determine the head gold grade. Each sample that returned results over 5 g/t Au was to be re-analyzed by gravimetric finish.
Bottle Roll Tests
A total of 25 composites were submitted for cyanide leaching bottle roll tests. The samples were composited from 70 individual coarse rejects selected from 15 diamond holes taken throughout oxidized, partially oxidized, and non-oxidized portions of fault-hydrothermal breccia hosted and veinlet gold mineralization. The coarse reject composite samples were ground to 95 percent less than 100 microns (# ASTM 150), homogenized, and split into 800 gram pulps. Each composite was tested with a 45 element ICP scan after multi-acid digestion.
Key reported parameters
| Parameter | Design / Proposed | Testwork Data | Basis |
|---|---|---|---|
| Screen fire assay grind size | Not specified | 95% passing 200# ASTM | Proposed for coarse residues |
| Gravity concentration feed size | Not specified | 100% passing 10# ASTM (2mm) | Proposed for 3 composites |
| Bottle roll test grind size | Not specified | 95% passing 100 microns (# ASTM 150) | Proposed for 25 composites |
| Number of samples tested | Not specified | 70 samples composited into 25 | Testwork on diamond drill core |
| Bottle roll sample mass | Not specified | 800 gram pulps | Proposed per composite |
| Gravity sub-sample mass | Not specified | 500 grams per sub-sample | Proposed per composite |
Project website: https://patagoniagold.com/
Technical qualifications
The report presents only proposed metallurgical testwork methods and initial sample preparation procedures. No actual test results, gold recoveries, cyanide consumption data, or processing performance outcomes are reported in the provided sections. The report does not specify a flowsheet, plant design, or final process route. The testwork was conducted on composited samples from 15 diamond holes, limited to the mineralized intervals selected for testing.
Source: Patagonia Gold: COSE Project (NI43-101), 20 August 2011, Section 17.0 Recovery Methods.
