In 2015, Sovereign’s in-country geological team made a new and significant graphite discovery using hand auger drilling techniques in an area of no outcrop. The deposit is located at Malingunde, just 15km SW of Lilongwe, Malawi’s capital city, and has access to enviable infrastructure. It is 25km from operating rail, 20km from a major power sub-station and has plentiful fresh water sources nearby.
The Malingunde deposit is hosted within weathered, soft saprolite (clay) material. Saprolite-hosted flake graphite mining operations, similar to those in China and Madagascar, usually have significant cost and environmental advantages over hard rock mining operations due to:
In 2017 Sovereign delivered the world’s largest reported soft saprolite-hosted graphite resource and scoping study, highlighting that the Project has capital and operating costs per unit at the very bottom of the graphite supply cost-curve.
The results of the Pre-Feasibility Study further demonstrate the potential for the Malingunde Project to support a very low capital and operating cost operation with annual graphite concentrate production of approximately 52,000 tonnes over an initial mine life of 16 years:
The production target generated by the Study is approximately 9.5Mt @ 9.5% TGC over a ~16 year mine life.
Saprolite is the very soft, graphite-bearing, clay-rich oxide material that is formed from intense weathering of the original bedrock.
The Malingunde deposit is located on the Lilongwe Plain which is underlain by a paragneiss basement rock package containing extensive graphitic units. This area has a largely preserved, deep tropical weathering profile containing significant thicknesses of saprolite. Because graphite is inert during the weathering process, it is preserved whilst most of the silicate gangue minerals are altered to clays.
The Malingunde deposit is large and high grade, with visually coarse and jumbo flake graphite identified throughout. Saprolite-hosted mineralisation has been identified in drilling over 3.4km of strike with cumulative across strike widths locally exceeding 200m and averaging about 120m. Grades of mineralised saprolite average around 8% TGC (nominal 5% TGC cut-off) with a number of coherent higher grade zones well above 10% TGC identified.
The maiden Mineral Resource Estimate (MRE) for the Malingunde deposit confirms it as world’s largest reported saprolite-hosted graphite resource. The total MRE is 65.1Mt @ 7.1% TGC at a 4% TGC lower cut-off grade and comprises:
At an increased 7.5% TGC lower cut-off grade, the saprolite-only resource is 8.9Mt @ 9.9% TGC
Sovereign controls a very large 3,788km2 tenement package, with the majority being prospective for saprolite-hosted flake graphite potential. Exploration to date has only “scratched the surface” of this potential, and current datasets suggest that there is potentially several hundred kilometres of cumulative strike length of saprolite-hosted graphite mineralisation in the area.
Bench-scale metallurgical test-work conducted in 2017 showed high grade concentrates with excellent flake distribution could be produced with a simple process flowsheet.
The overall consistency of the test-work results across 18 separate flotation tests indicates robust metallurgical behaviour which significantly de-risks the processing component for a potential future flake graphite operation at Malingunde.
The process flowsheet incorporates an upfront scrubber (similar to a trommel) to wash and disaggregate the graphite flakes from the host material prior to flotation. This provides significant capital & operational cost benefits over traditional hard-rock crushing and milling equipment.
Malingunde is located approximately 15km south-west of Lilongwe, Malawi’s capital, and boasts enviable access to services and infrastructure. The proximity to Lilongwe gives the project a number of benefits, including:
The Duwi Flake Graphite Project (“Duwi”) is located within Sovereign’s 100%-owned Exclusive Prospecting License EPL0372 in Malawi, near the capital city of Lilongwe.
At the Duwi trend, high-grade, coarse flake graphite mineralisation has been identified over a cumulative ~24km strike length. Around 2km of this trend has been drilled by Sovereign, resulting in the definition of the Duwi Main, Duwi Bend and Nyama graphite deposits, with a combined Mineral Resource Estimate of 85.9Mt at 7.1% TGC for 6.13Mt contained graphite.
Mount Isa Mines, a Glencore Company, manage and sole fund exploration on the following tenements comprising the Carpentaria Joint Venture (“CJV”):
|Mt Marathon||EPM 8586|
|Mt Avarice||EPM 8588|
|Fountain Range||EPM 12561|
|Corella River||EPM 12597|
|Saint Andrews Extended||EPM 12180|
Sovereign’s interest in the CJV is 24.91% as at 31 March 2019.