Defense Metals Corp. has received successful metallurgical test results for the Wicheeda rare earth element property from SGS Canada Inc. Results from the initial 21 of a planned 25 batch flotation tests completed to date during 2019 showed progressive improvement from early- to late-stage testing, culminating in test F21 that achieved:
- 80-per-cent recovery of cerium, lanthanum and neodymium oxides (Ce2O3-La2O3-Nd2O3);
- 44-per-cent rare earth oxide (REO) concentrate grade;
- 9.5 times upgrading ratio from head grade;
- 8.4-per-cent concentrate mass yield.
While additional testwork is required to replicate the F21 test results, based on publicly available research authored by SGS staff and Defense Metals‘ discussions with experts in the REE industry, the flotation response of the Wicheeda material is considered among the best in its class with relatively high upgrading ratios in comparison with other REE projects. The mass yield to the concentrate is also considered attractive for its potential to reduce acid consumption during the subsequent hydrometallurgical extraction stage. Reduced acid consumption has the potential to positively impact future economic studies for the Wicheeda REE project by contributing to reduced operating and/or capital costs. It is important to note that the current 2019 bulk sample batch flotation results are representative of the 30-tonne dolomite carbonatite surface bulk sample collected from the Wicheeda REE deposit (see Defense Metals‘ March 14, 2019, news release). Although the 2019 results are not necessarily representative of potential flotation performance of the deposit as a whole, the current batch flotation test results are in agreement with the 2011 flotation testwork, also conducted by SGS, on a composite 2009 drill core sample obtained from seven separate drill holes throughout the deposit.
The 2019 SGS flotation testwork is establishing a base case by confirming the reproducibility of previous 2011 metallurgical testwork, followed by process flowsheet optimization through researching the effects of various reagent combinations, in addition to varying grind size, flotation pulp temperature, pH and the possibility of gravity separation. An examination of Ce2O3 batch flotation test results to date reveals a progressive improvement of both rare earth oxide (REO) grade and overall REO recovery from base-case F1 to the current best test F21.
The 2011 base case returned projected trajectory mass balance REO recoveries for cerium, lanthanum and neodymium of 83 per cent at a grade of 42 per cent REO (see Defense Metals‘ Jan. 8, 2019, news release) based on combined locked-cycle concentrate recoveries of 62 per cent at a grade of 45 per cent REO.
Craig Taylor, chief executive officer of Defense Metals, stated: “We are extremely pleased with the Wicheeda batch flotation test results to date. With 80-per-cent recoveries at a rare earth oxide concentrate grade of 44 per cent, this places our Wicheeda bulk sample metallurgical testing at the high end of publicly reported concentrate grades and upgrading ratios for alkaline and carbonatite rock REE deposits. Defense Metals looks forward to the completion of additional batch flotation tests and locked-cycle flotation testing to establish a finalized process flowsheet.”
About the Wicheeda REE property
The Wicheeda 1,780-hectare property is located approximately 80 kilometres northeast of the city of Prince George, B.C., is readily accessible by all-weather gravel roads and is nearby to infrastructure, including power transmission lines, the CN railway and major highways.
Geologically, the property is situated in the Foreland belt and within the Rocky Mountain trench, a major continental geologic feature. The Foreland belt contains part of a large alkaline igneous province, stretching from the Canadian Cordillera to the southwestern United States, which includes several carbonatite and alkaline intrusive complexes hosting the Aley (niobium), Rock Canyon (REE) and Wicheeda (REE) deposits.
The Wicheeda property is underlain by Kechika group metasedimentary rocks that are intruded by the southeast-trending Wicheeda carbonatite; a deformed plug or sill approximately 250 metres in diameter that hosts significant REE mineralization. This intrusion comprises a ferroan dolomite carbonatite core, which passes gradationally outward into calcite carbonatite. The REE mineralization is hosted by the dolomite carbonatite.
The scientific and technical information contained in this news release as it relates to the Wicheeda property has been reviewed and approved by Kristopher J. Raffle, PGeo (B.C.), principal and consultant of APEX Geoscience Ltd. of Edmonton, Alta., a qualified person as defined in National Instrument 43-101 — Standards of Disclosure for Mineral Projects.
Methodology and quality assurance/quality control
Batch flotation head grade and concentrate products for lanthanum and neodymium oxides were determined by whole-rock analysis, via lithium-borate fusion of a 0.5-gram sample analyzed via wavelength dispersion X-ray fluorescence (WD-XRF). The remaining rare earth elements were determined via 0.5-gram sodium-peroxide fusion multielement ICP-MS (inductively coupled plasma mass spectrometry).
The SGS analysis included a quality assurance/quality control (QA/QC) program including the insertion of rare earth element standard and blank samples. Defense Metals detected no significant QA/QC issues during review of the data. SGS Minerals Lakefield is ISO/IEC 17025 and ISO9001:2015 accredited. SGS is independent of Defense Metals.