TSX-V-listed Cypress Development has announced positive results from a preliminary economic assessment (PEA) of the company’s Clayton Valley lithium project in Nevada, in the US.

Prepared by Colorado-based engineering services firm Global Resource Engineering, the PEA focuses on a mine producing an average of 24 042 t/y of lithium carbonate over 40 years.

With a base case lithium carbonate price assumption of $13 000/t , the PEA returned a net present value of $1.45-billion, at a discount rate of 8%, and a 32.7% internal rate of return on after-tax cash flow.

The capital cost is estimated at $482-million, with the preproduction and operating cost estimate averaging $3 983/t of lithium carbonate.

The PEA is based on a May 2018 mineral resource estimate of an indicated resource of 831-million tonnes at 867 ppm lithium, or 3.835-million tonnes lithium carbonate equivalent.

Following upon changes in the resource model and property boundaries since the resource estimate in May, the mineral resource estimate also includes an inferred resource of 1.12-billion tonnes at 860 parts per million lithium, or 5.126-million tonnes lithium carbon equivalent.

Declaring the PEA’s positive results an important milestone for the project and company, Cypress CEO Dr Bill Willoughby on Thursday outlined the steps necessary for a mine and mill at Clayton Valley, including a sulphuric acid plant, which is the main driver in the costs.

Using a conventional approach in processing, he explained that GRE had developed a production schedule that used only a small fraction of the total resources on the property.

“The end result is a project that has strong economics and the potential to generate significant cash flow,” he noted.

A 15 000 t/d nominal production rate was selected based on the projected output for the operation, with the goal of producing 20 000 t/y of lithium carbonate.

The plant design by GRE includes agitated tank leaching, and a multi-stage thermal-mechanical evaporation system for concentrating leach solution.

GRE recommends further work, including bench scale testing, to demonstrate the recovery of lithium product, which Cypress intends to proceed with “as soon as possible”.

The company will continue to work on permitting and other areas to advance the project, which is located immediately east of Albemarle’s Silver Peak mine – North America’s only lithium brine operation.