Sinclair Caesium Mine

The Sinclair Pegmatite is classed as a complex Lithium-Caesium-Tantalum (LCT) pegmatite due to its extreme mineral fractionation. This has resulted in the formation of a suite of mono-mineralic phases that include pollucite (Cs) as well as petalite and lepidolite (Li), feldspar (K) and silica (Si).

Pollucite is a rare caesium mineral found in only the most extreme differentiated LCT pegmatite systems. The world’s supply of pollucite is highly constrained, and the Company’s discovery was significant. Pollucite is primarily used in the manufacture of Caesium Formate brine, a high-density fluid used in high temperature/high pressure oil and gas drilling. It acts as lubricant and helps deliver higher production rates and is non-corrosive and environmentally friendly.

Mining activities commenced in September 2018 at the Sinclair Caesium Mine lasting four months. Crushed caesium bearing ore was then sold under and offtake agreement with final sales being completed in June 2020. A Project Operating Cash Surplus of A$10 million was generated.

A geological review of the existing data generated from Stage 1 mining activities and drilling outside the pit shell demonstrates that additional caesium-bearing pollucite lenses exist just outside the northern pit wall and extend for at least 80m to the north.

Investigations have commenced to determine:

  • What further drilling information is needed;
  • Which mining method is more suitable – open pit cut-back or ‘airleg’ style underground mining from the pit floor;
  • Potential off-take partners for a Stage 2 mining operation;
  • Opportunities to ‘value add’ given that caesium in a semi-finished or finished form can command significant premiums to already valuable crushed ore.