ValOre Reports Further Encouraging Metallurgical Testing Results from Pedra Branca PGE Project: 91% palladium recoveries in cyanide leach and 82% platinum recovered in 32% mass in gravity sort
November 9, 2020
November 9, 2020
Vancouver, B.C. ValOre Metals Corp. (“ValOre”; the “Company”; TSXâ€źV: VO; OTC: KVLQF; Frankfurt: KEQ0)today announced preliminary metallurgical results for cyanide leach and Falcon Ultra-Fine (“UF”) testwork for ValOre’s 100%-owned Pedra Branca Platinum Group Element (“PGE”) Project in northeastern Brazil.
“We are extremely pleased with both the high palladium recoveries achieved with cyanidation tests and the gravity concentration tests which showed more than 80% of the platinum recovered in 32% of the mass,” stated ValOre’s Chairman and CEO, Jim Paterson. “These favorable and complimentary results significantly increase the optionality related to future development of the Pedra Branca project and they provide real impetus for ValOre to continue to perform tests to optimize conditions and improve metallurgical recoveries.”
Highlights from Cyanide Leach and Falcon UF Gravity Tests at Pedra Branca
- Hot cyanide metallurgical test recoveries of 84.4%, 88.5% and 91.7% palladium (“Pd”) were achieved;
- Falcon UF gravity test work was very effective at concentrating platinum (“Pt”) with 73.3% Pt recovered in only 9.6% of the mass and 82.6% Pt recovered in 32.1% of the mass;
- Falcon UF gravity concentration may serve to optimize conditions required for the Platsol™ process (see news release date November 2, 2020) by favorably rejecting acid-consuming minerals, and consequently, three subsequent Platsol™ optimization tests have been initiated.
PGE Cyanidation Testwork
Palladium and platinum are readily soluble in a cyanide leach solution under certain chemical conditions. To assess the potential of cyanide leaching as a means to recover PGEs at Pedra Branca, three initial 48-hour hot cyanide leach tests were conducted at SGS Lakefield, Ontario (“SGS”). These tests were conducted on: 1) composite drill core sample from the Curiu 2PGE+Au deposit (100,000oz at 1.93 g 2PGE+Au/t); 2) an outcrop sample from the Trapia 2PGE+Au deposit (219,000oz at 1.19 g 2PGE+Au/t); and 3) tailings material collected from the first Falcon UF Gravity Concentrator test (see “Falcon UF Gravity Separation” below). Recoveries of 84.4%, 88.5% and 91.7% Pd were achieved in 48-hour leach experiments. See Table 1 below for a summary of cyanidation results, and Table 2 below for a description of sample details.
The hot cyanide leach tests were performed with the following conditions:
- Grind size = 20-30 μm (P80)
- Pulp density = 33% solids (w/w)
- Pulp temperature = 50°C
- Cyanide concentration = 20 g/L NaCN (maintained)
- Dissolved Oxygen = 20 mg/L (maintained)
- Retention time = 48 hours
- Kinetic solution subsamples assayed for Pt and Pd after ~6, 24 and 48 hours
Table 1: Summary of Hot Cyanide Leach Results
|Sample||Tailing from Test||% Extraction|
|6 h||24 h||48 h||6 h||24 h||48 h|
|Trapia West Outcrop||--||2||3||4.2||47||74||84.4|
Table 2: Description of Sample Details
|Historical Drill Core||Curiu Deposit||20-25 kg||3.83||6.86||0.25||0.24||11.2|
|Outcrop||Curiu Deposit||20-25 kg||7.86||3.95||0.45||0.30||12.6|
|Outcrop||Trapia West Deposit||20-25 kg||21.6||17.0||0.25||0.83||39.6|
The strong leachability of Pd in all three tests warrants subsequent cyanidation tests aimed at improving the performance of Pt recoveries. The addition of chloride and/or iodine as an additive in future testing may promote reaction activity and this could positively impact the recoveries of both Pt and Pd.
About Cyanidation of PGEs
Further information about cyanide leaching can be found in the link below:
Falcon UF Gravity Separation
Previous mineralogical studies of Pedra Branca mineralized ultramafic rocks suggest a very fine nature to the PGE minerals (<9 micrometer (“μm”)) and thus multiple rounds of testwork have been initiated to assess the potential to upgrade feed material by means of a fine grind (-20 to -38 μm) followed by gravity separation using the Falcon UF Gravity Concentrator. The primary objective is to scavenge ultra-fine mineral particles that are typically rejected from conventional gravity processing circuits as slimes.
The first round of Falcon UF testwork (“G1”) was completed on a sample of historical drill core from the Curiu 2PGE+Au deposit (NI 43-101 resource of 100,000oz 2PGE+Au at 1.93 g/t). A summary of the samples tested is included in Table 2 above. Platinum responded very favorably to Falcon UF Gravity concentration, with 73.3% Pt separated into only 9.6% of the mass, 82.6% Pt separated into 32.1% of the mass, and 57.8% Pt on the first mass pull (4.6% of the mass). Palladium responded less favorably to Falcon UF concentration, with 47.7% Pd recovered in 32.1% of the mass. See Figure 1 and Table 3 below for a summary of G1 test results, which were run under the following test protocols: 5 kg feed at -38 μm, 10-15% solids with ~ 3 litres/minute pulp feed rate.
- 300 G-Force centrifugal pressure
- Recover Pass 1 Concentrate and retain
- Repass Pass 1 Tailing
- Repeat for a total of 8 passes – expected mass recovery of 20-25% in total
- Filter, dry and weigh all products and submit for assay (8 concentrates, 1 tailing), including Cr, Pt and Pd
- Metallurgical balance relating mass recovery to PGE recovery
Figure 1: Summary Graph of G1 Falcon UF Gravity Test Results
Table 3: Summary Table of G1 Falcon UF Gravity Test Results
|Product||Mass||Assays, g/t||Distribution %|
|g||%||Pt, g/t||Pd, g/t||Cr, %||Pt||Pd||Cr|
|Pass 1 Concentrate||226.7||4.6||44.5||21.9||15.1||57.8||15.0||8.6|
|Pass 1+2 Concentrate||477.3||9.6||26.8||17.9||16.8||73.3||25.9||20.1|
|Pass 1-3 Concentrate||707.1||14.2||19.0||15.1||17.1||77.0||32.3||30.2|
|Pass 1-4 Concentrate||921.6||18.5||15.0||13.2||16.9||79.0||37.0||39.0|
|Pass 1-5 Concentrate||1121.0||22.5||12.5||11.9||16.4||80.2||40.4||46.1|
|Pass 1-6 Concentrate||1297.9||26.1||10.9||11.0||16.0||81.2||43.3||52.0|
|Pass 1-7 Concentrate||1455.6||29.2||9.8||10.3||15.6||82.0||45.5||56.9|
|Pass 1-8 Concentrate||1600.1||32.1||9.0||9.8||15.4||82.6||47.4||61.6|
Given the strong performance of Pt concentration in the G1 test, a subsequent round of Falcon UF concentration testwork (“G2”) was performed, aimed at further improving recoveries by a sequential coarse-to-fine grind. G2 was designed to examine the response of coarsely ground (~100 µm P80) material to standard gravity recovery techniques (Wilfley table), followed by fine grinding of the tailing (P80 = ~20 µm) and processing at high G-Force with the Falcon UF test procedure. This assumes that the PGEs were predominantly associated with chromite and that coarse chromite may concentrate somewhat efficiently relative to the lighter matrix minerals.
Platinum once again responded well to the combined Wilfley + Falcon UF process, with 76.4% recovered in 30.6% of the mass (Wilfley concentrate + Falcon pass 1 concentrate), and 86.9% recovered in 56.1% of the mass in the combined Wilfley + 4 pass Falcon concentrate. Palladium showed a slight improvement to G1 results, but required a higher mass pull, with recovery curves flattening at ~30% mass pull. The Wilfley stage did not show a marked improvement on G1 results. CLICK HERE for Figure 2 and Table 4 for summaries of the G2 test results.
The strong performance of Pt in both the G1 and G2 Falcon UF gravity tests, combined with strong leachability of Pd seen in the three cyanidation tests presents two highly complementary processes to concentrate and recover Pd and Pt at Pedra Branca. High-priority follow-up testwork is planned to further optimize conditions and improve metallurgical recoveries.
About Falcon UF Gravity Separation
Further information about Falcon UF gravity separation can be found in the link below:
SGS is the world’s leading inspection, verification, testing and certification company. SGS is recognized as the global benchmark for quality and integrity. With more than 89,000 employees, SGS operates a network of more than 2,600 offices and laboratories around the world.
SGS fit-for-purpose solutions encompass the skills of qualified geologists, geostatistician, analytical chemists, mineralogists, metallurgists, process engineers and mining engineers brought together to provide accurate and timely mineral and process evaluation services across the entire mining life cycle.
Qualified Person (QP)
The technical information in this news release has been prepared in accordance with Canadian regulatory requirements set out in NI 43-101 and reviewed and approved by Colin Smith, P.Geo., ValOre’s QP, who oversees New Project Review for ValOre.
About ValOre Metals Corp.
ValOre Metals Corp. (TSXâ€źV: VO) is a Canadian company with a portfolio of highâ€źquality exploration projects. ValOre’s team aims to deploy capital and knowledge on projects which benefit from substantial prior investment by previous owners, existence of high-value mineralization on a large scale, and the possibility of adding tangible value through exploration, process improvement, and innovation.
In May 2019, ValOre announced the acquisition of the Pedra Branca Platinum Group Elements (PGE) property, in Brazil, to bolster its existing Angilak uranium, Genesis/Hatchet uranium and Baffin gold projects in Canada.
The Pedra Branca PGE Project comprises 38 exploration licenses covering a total area of 38,940 hectares (96,223 acres) in northeastern Brazil. At Pedra Branca, 5 distinct PGE+Au deposit areas host, in aggregate, a NI 43-101 Inferred Resource of 1,067,000 ounces 2PGE+ Au contained in 27.2 million tonnes grading 1.22 g/t 2PGE+Au (see ValOre’s July 23, 2019 news release). PGE mineralization outcrops at surface and all of the currently known inferred resources are potentially open pittable.
Comprehensive exploration programs have demonstrated the "District Scale" potential of ValOre’s Angilak Property in Nunavut Territory, Canada that hosts the Lac 50 Trend having a NI 43â€ź101 Inferred Resource of 2,831,000 tonnes grading 0.69% U3O8, totaling 43.3 million pounds U3O8. For disclosure related to the inferred resource for the Lac 50 Trend uranium deposits, please refer to ValOre's news release of March 1, 2013.
ValOre’s team has forged strong relationships with sophisticated resource sector investors and partner Nunavut Tunngavik Inc. (NTI) on both the Angilak and Baffin Gold Properties. ValOre was the first company to sign a comprehensive agreement to explore for uranium on Inuit Owned Lands in Nunavut Territory and is committed to building shareholder value while adhering to high levels of environmental and safety standards and proactive local community engagement.
On behalf of the Board of Directors,
"Jim Paterson"James R. Paterson, Chairman and CEO
ValOre Metals Corp.
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