Sampling and Analysis and Data Verification
All samples used for resource estimations for the Titiribi Project were from diamond drill core and all cores were assayed. Samples are generally 1.5 m to 2 m in length. The maximum sample length is 2 m. Samples may deviate from the 2 m standard, if there is a change in lithology. Sunward placed a small sticker for the start and finish of each interval to be sawn. One half of the core was sent off for assay and the other half of the core was retained for future reference. On average, the assay split weighed between 3 kilograms and 7 kilograms. Samples were placed in bags printed with the sample numbers and a ticket with the sample number was placed inside the bag. The sample was weighed, recorded, and placed in a transport bag. The samples were secured until delivered to the sample preparation facility in Medellin.
For all labs, the Sunward procedure called for crushing the 1/2 core sawn sample to 80% minus 10 mesh. Through a riffle splitter, a 50-50 split is obtained with one-half returned to Sunward as a coarse reject. About 250 grams are split out and pulverized to 80% to 85% minus 150 mesh. Typically, a one-assay tonne sample is used for the assay samples and the remainder of the pulp is returned to Sunward. For some laboratories, an 800-gram sample is pulped, allowing for metallic screen assays to be performed.
Quality Assurance/Quality Control ("QA/QC") measures used included utilizing blanks, standards re-run assays and duplicate core splits. Field blanks were comprised of cuts of barren granodiorite from a dimension stone cutting company based in Medellin. International certified standards were purchased from several reference material companies. Twenty-eight different certified gold standards and eleven certified copper standards were utilized by Sunward during their exploration drilling campaigns. Blanks and certified standards were inserted into the sample stream on a regular basis. During the 2012-2013 drilling campaign, a blank and a standard were inserted into the sample stream every 18th core sample. Results for the blank and standard samples were checked for deviation from expected values. Additionally, a duplicate split consisting of a quarter core was also collected on a less regular basis.
All samples were under the control of Sunward's technical personnel from the time holes are cored until samples are received in Medellin for sample preparation. A number of laboratories have been used for analysis, which were independent of Sunward and the Company.
Metallurgical test work was completed from 2011 through early 2012. No new metallurgical testing has been undertaken since 2012.
In 2011, Sunward engaged Tetra Tech Inc. to carry out preliminary metallurgical investigations on mineralized samples from the Titiribi Project. They contracted Resource Development Inc. of Golden, Colorado and for the Phase II program, four samples of 75 kilograms were investigated. The principal results disclosed by the Company were:
| ● | For all four samples tested, a significant proportion of the gold could be upgraded by gravity; |
| ● | The samples were all non-refractory and cyanidation of the head samples, or the gravity or flotation concentrates, successfully recovered gold; and |
| ● | Flotation of the Cerro Vetas sample produced a saleable copper concentrate with high gold and copper recoveries. |
In 2012, TJ Metallurgical Services was asked by Sunward to develop a suitable test work program that would identify an optimized process flow sheet and determine the key metallurgical design parameters. The UK laboratory of Wardell Armstrong International ("WAI") was selected and 3 samples weighing 270 kilograms to 300 kilograms from Cerro Vetas, NW Breccia, and Chisperos were sent to the Cornwall laboratory. The work carried out covered:
| ● | Extensive Head Sample Investigations. XRD, ICP, Abrasion Indices and Bond Work Index determinations; |
| ● | Knelson Gravity Test Work. Three 50 kilogram samples were dispatched to FLSmidth-Knelson for Gravity Recoverable Gold ("GRG") testwork and a determination of the gold that could be recovered to a final product; |
| ● | Gold Deportment Investigations on Gravity and Flotation Concentrates. This included Diagnostic Leach testwork, Qemscan, and SEM investigations to determine the gold association and to plan the subsequent metallurgical test work; |
| ● | Flotation Testwork. Reagent and flotation optimisation for all three samples tested. Cleaner test work with optimised flotation reagent regime; |
| ● | Locked Cycle Flotation Testwork. Nine tests were carried out in total with six being carried out on Cerro Vetas to maximise the Au and Cu recovery to a copper flotation concentrate; |
| ● | Cyanidation Testwork. Pyrite flotation concentrates were produced from all three samples and the Au recovered by cyanidation; |
| ● | Detailed Cyanidation Testwork. A large bulk pyrite concentrate was produced from NW Breccia and a six-test cyanidation testwork programme was carried out; and |
| ● | Environmental Testwork. TCLP leach tests, ABA investigations and NAP/NAG tests were carried out on the flotation tailings. An Inco-type cyanide detox test was also carried out on the NW Breccia cyanide leach tailings. |
The metallurgical work was reported by WAI in the report 'Stage III Metallurgical Testing on Samples of Gold and Copper Mineralization' ZT64-0386, May 2013. The principal results obtained were:
| ● | Gold Deportment. For all samples, around 10%-12% was recoverable to a gravity concentrate. The gold was not liberated and was generally locked with sulphides but was amenable to cyanidation. For Cerro Vetas, 57% was recoverable to a copper concentrate and 13% to a pyrite concentrate. For NW Breccia and Chisperos, the majority was associated with pyrite and was also amenable to cyanidation; |
| ● | Knelson GRG Tests. Samples of Cerro Vetas and NW Breccia were sent for testwork at FLS-Knelson. FLS reported that for Cerro Vetas and NW Breccia there was a significant GRG element in both samples of 39.8% and 64.8% respectively. More importantly, they stated that the introduction of a Knelson circuit and a cyanidation circuit would lead to an additional Au recovery of 1.2%-1.8% and 4.0%-5.6% for Cerro Vetas and NW Breccia, respectively. Chisperos was not tested; and |
| ● | Locked Cycle Flotation Testwork. These tests replicate plant practice by recirculating intermediate streams and give the best indication of the grades and recoveries that can be achieved in an operating flotation plant. Using the optimized collector MX-5125 with other collectors in combination, the following results were obtained for Cerro Vetas. |
| Table B-2 Cerro Vetas Locked Cycle Flotation Tests |
|---|
| Test No. · Cu Con Grades · Cu Con Rec (%) · Pyrite Con |
|---|
| Cu | Au | Wt% | Cu | Au | Wt% | Au gpt | Au Rec |
|---|
| LCT1 | 15.7 | 30.3 | 1.25 | 86.9 | 69.5 | 0.35 | 5.5 | 3.5 |
|---|
| LCT2 | 24.4 | 50.0 | 0.76 | 86.7 | 76.5 | 0.70 | 3.0 | 4.2 |
|---|
| LCT3 | 18.8 | 34.4 | 1.24 | 90.3 | 76.7 | 0.80 | 5.1 | 7.3 |
|---|
| LCT4 | 21.7 | 41.8 | 1.02 | 90.1 | 78.4 | 0.63 | 5.5 | 6.4 |
|---|
| LCT1 (blend) | 19.5 | 39.1 | 0.95 | 88.6 | 69.1 | 0.96 | 3.8 | 6.9 |
|---|
| LCT2 (blend) | 16.7 | 30.3 | 1.17 | 90.2 | 65.2 | 1.03 | 3.9 | 7.4 |
|---|
LCT3 reported the best results and LCT4 was a repeat with the same conditions. Very similar results were reported. The LC tests indicate that a saleable copper concentrate can be produced with a copper recovery of 90% and a gold recovery of 77%. The flotation of a pyrite concentrate recovers a further 6% gold.
The two Locked Cycle blend tests are on a feed composite of Cerro Vetas and NW Breccia in a blend of 9:1.
Two Locked Cycle tests were carried out on a sample of NW Breccia and one Locked Cycle test on Chisperos.
| Table B-3 NW Breccia and Chisperos Locked Cycle Flotation Tests |
|---|
| Test No. · Pyrite Con Grades · Pyrite Con Recoveries |
|---|
| %S | Au gpt | Wt% | %S | %Au |
|---|
| NW Breccia: |
|---|
| LC1 | 44.5 | 12.4 | 3.7 | 59.9 | 85.3 |
|---|
| LC2 | 39.8 | 6.1 | 6.4 | 93.2 | 90.1 |
|---|
| Bulk Float | 39.1 | 11.2 | 6.4 | 94.5 | 95.7 |
|---|
| Chisperos: |
|---|
| LCT1 | 50.3 | 12.3 | 5.0 | 92.6 | 92.9 |
|---|
The NW Breccia 'Bulk Float' test was a test on a 20 kilogram feed sample to generate a 1.25 kilogram pyrite flotation concentrate for a cyanidation testwork program. The results indicate that over 90% of the gold can be recovered to a pyrite flotation concentrate for both NW Breccia and Chisperos.
| ● | Pyrite Concentrate Cyanidation Testwork. The six-test optimization program showed that it was not necessary to regrind the pyrite flotation concentrate to achieve high gold recoveries and an average gold recovery of 91.7% with a cyanide consumption of 5.2 kg/t was achieved. |
| ● | Environmental Testwork. The environmental characterization tests did not report any issues with regard to acid generation. |
The WAI testwork identified the following process flow route to treat a Cerro Vetas ROM ore or a blend of Cerro Vetas with a minor proportion of NW Breccia:
| ● | Comminution circuit to produce a flotation feed with a P80 of 90 microns; |
| ● | Knelson circuit within the comminution circuit to recover a gravity concentrate; |
| ● | Copper flotation circuit to produce a copper concentrate as filtercake; |
| ● | Pyrite flotation circuit; and |
| ● | Small cyanidation circuit to treat the Knelson gravity concentrate and the pyrite flotation concentrate and produce Au/Ag doré. |
From a series of Locked Cycle flotation and detailed cyanidation tests, the WAI testwork program has identified the likely copper and gold recoveries that could be achieved from a standard two-circuit flotation plant with a small cyanidation circuit.
