Sustainability
Off-grid power generation
Ioneer’s planned processing facility includes a sulfuric acid plant and related steam turbine, which will allow the Company to produce sufficient electricity to power its entire operation. This means zero reliance on the Nevada electrical grid and minimal use of fossil fuels to produce needed electricity. Electricity generated in this manner produces minimal CO2 emissions and minimal hazardous air pollutants and is considered green co-generation.
Mining fleet – Autonomous and electrification
The results of the Rhyolite Ridge feasibility study show the viability of AHS at the mine and the proposed application of AHS could positively impact the overall cost structure of the operations. Key anticipated drivers include increased operating hours, reduced cycle times and improved cycle efficiency, and decreased operating costs in terms of maintenance, fuel, labour, and tires.
AHS should also lead to improve in-cycle productivity and overall utilisation, reducing the number of trucks required. Cat autonomous mining trucks have safely hauled more than 2 billion tonnes of material worldwide, driving over 67.6 million kilometres without a lost-time injury
The operations are scheduled to start in 2023 with a fleet of Cat® 785 Next Generation mining trucks equipped with Cat® Command for hauling, and the fleet is scheduled to expand significantly in year four.
All support equipment will feature the latest MineStar technology utilising high-precision GPS and real-time analytics to maximise efficiency and accuracy in material loading. This will be the first greenfield operation in North America to utilise AHS and will mark the expansion of Command for hauling automation technology to the 140-tonne class Cat® 785 Next Generation mining truck.
Water supply and recycling
Water use associated with Ioneer’s production of materials is extremely low compared to other lithium producers, especially those that utilize brine extraction and solar evaporation. The design is optimised to reduce water demand and will recycle a majority of the water used in the refining process.
The quarry lake mentioned above is expected to form in the quarry after dewatering ceases. For evaluating quarry lake impacts, three scenarios were simulated: a base case (expected); scenario that simulated the quarry lake refilling with a higher hydraulic conductivity; and another with a lower hydraulic conductivity. In all cases, the quarry lake is predicted to stabilise below the local, pre-mining groundwater elevation, resulting in a long-term stable hydraulic sink around the quarry.
In-pit dewatering will be necessary in all stages of quarry progression to maintain a dry, stable floor, as the lower hydraulic conductivity Cave Springs formation provides a barrier to groundwater flow in the quarry. Dewatering rates are predicted to range from 65 to 120 gallons per minute. A minimum of one dewatering area will be maintained at all times in the lowest area of the pit floor. This water will be pumped out of the quarry using dewatering pumps where it will be sent to the process circuit for reuse. Stormwater controls will be constructed around the perimeter of the pit, before the quarrying process begins in the respective area, to limit the quantity of water in the pit.