Perpetual Resources Ltd (ASX:PEC) has obtained strong results from recent testing of the white sand horizon at its Beharra Silica Sand Project, achieving an end product with 99.8% silicon with very low impurities.
The results, including an "exceptionally" low impurity profile of 120 parts per million (ppm) iron and 920 ppm aluminium, have been described by the company as being game-changing.
While an extremely high processing yield of 95% was also reported, Perpetual expects a scalable production scenario to lead to lower yields, albeit it is expected they will be materially higher than the 74% that was reported in the recent PFS test work.
“Clear potential to be a genuine tier-1 project”
Executive chairman Julian Babarczy said: “We initially acquired the Beharra project with the geological theory that it contained a pervasive and high purity white sand horizon.
“Our recent PFS study demonstrated a highly economic and compelling project if we were to mine and process both the white and yellow sand horizons together.
“These results today suggest that Beharra has clear potential to be a genuine tier-1 project and we are now considering a development scenario that undertakes selective mining and processing of the white sand horizon that has now been shown to achieve impurity levels that could underpin even higher revenue per ton figures than were contemplated in the recent PFS.
“We will now launch straight into a drilling and bulk metallurgical program conducted at feasibility study-level, which we expect will demonstrate that the PFS numbers we recently reported can be materially enhanced.”
Increase in overall product quality
These results represent a substantial increase in overall product quality when compared to the PFS results, with 0.2% higher silicone content and, even more importantly, extremely large reductions in the key impurities with a reduction of 57% in iron and a reduction of 49% in aluminium.
These results demonstrate that the white sand horizon at Beharra can produce a very low impurity product using simple gravity and magnetic separation techniques, with confirmation as to the end-product quality that is achievable under a scalable production scenario now to be tested to a feasibility study level with planning for a drilling and metallurgical program currently underway.
Beharra white sand endowment
On March 9, Perpetual updated its mineral resource estimate prepared by Snowden Mining Consultants, which upgraded the previously inferred mineral resource estimate to indicated status.
The Beharra MRE contains more than 90% white sand, which is overlain by a modest sequence of yellow sand of varying thickness.
The ability for Perpetual to selectively mine the white sand sequence is considered extremely high, due to the simple geology and the strong visual break that exists between the yellow and white sand horizons.
Follow-up feasibility study drilling
Perpetual has commenced planning for a follow-up drilling and metallurgical testing program, which will underpin and guide efforts for the next phase of project studies at Beharra.
The company will begin an air-core drilling program over an area representing the first ten years of the planned mining area at Beharra in May with drilling contractor and rig selection already underway.
This program should take around two weeks to complete, including mobilisation and demobilisation efforts.
Samples will then be sent to IHC Robins in Brisbane for full metallurgical evaluation, based on the previously defined flow sheet that formed part of the Beharra PFS study, with subsequent test work expected to further refine the likely processing flow sheet for use in the subsequent Beharra project study, enhancing the estimation of process plant capital and operating costs.
Other goals of the metallurgical test work include the determination of high purity silica sand final product specifications that will be utilised for ongoing marketing efforts of the Beharra end product.
This metallurgical testing program is expected to take six to eight to complete, with results expected to be announced by the end of July 2021.