“The Eldor Carbonatite and the Ashram Rare Earth Deposit”
by Darren Smith, M.Sc., P.Geol., Project Geologist / Manager, Dahrouge Geological Consulting Ltd.
The Eldor Carbonatite Complex, held by Commerce Resources Corp., is located in north-central Quebec within the Labrador Trough, which is part of the Paleoproterozoic New Quebec Orogen. The carbonatite intrudes a series of meta-volcanic and meta-sedimentary rocks at the contact between the meta-volcanic rocks to the west and Proterozoic gneisses to the east. The complex is elliptical in shape with dimensions of 8 x 4 km as inferred by airborne magnetics.
The geology of the Eldor Carbonatite is very complex, with several lithological subdivisions proposed/identified and separate eruptive centres postulated. Simplistically, the Eldor Complex can be separated into three major divisions: early, mid-, and late-stage carbonatite. The mid-stage carbonatite is most closely related to tantalum-niobium mineralization (pyrochlore, columbite) with late-stage carbonatite crosscutting all earlier phases and is the primary host to the rare earth element (REE) mineralization observed at the Ashram Deposit.
The carbonatite is thought to have undergone minimal weathering, mainly due to the sub-arctic climate, with glaciation thought to be the major eroding force. Only a thin veil of overburden covers the complex, with fresh rock being encountered essentially at the soil-rock interface. This geological history prevented the formation of the deep lateritic weathering profile that sometimes proves problematic in rare earth deposits due to rare earth mineral re-crystallization etc.
The REE bearing Ashram Deposit is located central to the complex, within a magnetic low approximately 0.8 x 1.0 km in size, in-between two strong semi-circular magnetic highs. The deposit outcrops at surface and was discovered via prospecting in 2009 through tracing back mineralized boulders to their source. Subsequent drilling has returned strong and consistent REE mineralization of up to 2.10% TREO over 586 m and defined a measured and indicated resource of 29.3 million tonnes at 1.90% TREO and an inferred resource of 219.8 million tonnes at 1.88% TREO making Ashram one of the largest rare earth deposits in the world.
The Ashram Deposit is highly unusual in that it has an abnormally high percentage of the middle and heavy rare earths due to the presence of xenotime, in addition to the main rare earth bearing minerals monazite and bastnaesite. This enrichment is more prevalent central to the deposit, extending from surface.
Currently, the deposit’s geometry and geology can best be described as a moderate to steeply NE dipping ovoid or sheet, with simple rare earth mineralogy (monazite, bastnäsite, xenotime). Although mineralogically simple, it is texturally complex with multiple later stage episodes of dolomitic carbonatite emplacement (ferro/magnesio), coupled with deformation and brecciation (cataclasis), and low-temperature hydrothermal overprinting. No major off-setting structures have been identified within the main ore body, however, additional drilling and ongoing interpretation is required.
The primary targets of the exploration program on the Eldor Property are Nb-Ta and REE mineralization. Recent (2007 to 2013) field work has recognized that as well as Nb-Ta and rare earths, the complex has a multi-commodity potential, with appreciable local enrichment in phosphate and fluorine. The complex continues to yield exploration opportunity with the recent Ashram discovery a testament to the potential carbonatite complexes inherently display.
Darren Smith graduated from Carleton University with Bachelor of Science (Hon) Geology / 2003 and Master of Science in Geology / 2005.
Darren joined Dahrouge in early 2006. His primary role with Dahrouge has been high-level project management, implementation, reporting, and land management. Darren has provided technical oversight for PEA and PFS level project advancement and has setup and monitored complex metallurgical programs. His experience includes carbonatite complexes and associated rare metals, rare earth elements, sandstone-hosted and unconformity-style uranium deposits, as well as base and precious metals.
In 2008, he began to oversee a developing carbonatite (Ta-Nb-Phosphate-F, REE) project located near Kuujjuaq, Quebec and continues to devote the majority of his time to this Property (Eldor). During exploration of the Eldor Property in 2009, Darren and his team discovered one of the world’s largest REE deposits (Ashram) and are now completing work in support of a Pre-Feasibility Study.
Darren offers high-level Project Management and has achieved notable success with the advancement of the Ashram Rare Earth Project (Eldor Property) in northern Quebec. As the Project Manager for the Eldor Property, Darren is responsible for all facets of the exploration, which includes: field programs, land management, assessment reports, news releases, multiple drill supervision, community consultation work, organization of airborne and ground geophysical surveys, all aspects of post data compilation, metallurgical organization and sourcing, as well as managing as many as 35 members of the geological team in a remote camp setting.
The Calgary Mineral Exploration Group Society offers monthly lunchtime seminars relating to geology and mining in the province of Alberta, across Canada and around the world.
|MEG Calgary Monthly Luncheons – held the first Thursday every month|
|LOCATION||Ramada Hotel Downtown
708 – 8th Avenue SW
|TIME||Doors Open at 11:30AM
Talks Commence at 12:00PM
Please confirm your intention to attend by email to vtrapnell@MEGCalgary.com so that the appropriate number of sandwiches can be ordered.
If you would like to present a lunch time talk to a keen audience of 50 or 60 professionals, please contact Glen Jones at GlenJ@IntierraRMG.com or telephone: 403-202-8683; Mobile: 403-651-3086 to submit your topic and abstract for review. If you or your company would like to sponsor a meeting please contact Glen Jones for further information.