VRX SILICA LIMITED VRX Silica Limited announced an update to the Mineral Resource Estimate (MRE) and Ore Reserve Statement (ORS) for its Arrowsmith North Silica Sand Project, located 270km north of Perth. The MRE update is based on an additional 130 close spaced grade control holes1. These holes were drilled as a pre-production activity to increase the resource confidence in the initial years of mining, and to produce a bulk sample for pilot scale metallurgical testwork and the generation of bulk samples for potential offtake partners.
The pilot plant testwork of a 3.3 tonne bulk metallurgical composite is complete. In combination with market analysis a suite of 5 saleable products have been determined that will be produced from Arrowsmith North. Process and Engineering design of the proposed Process Plant has been guided by the chemical and physical specifications of these products.
The declaration of these five products is used to define the saleable Ore Reserve declared in this Statement. The creation of this proved ore reserve has led to a high confidence schedule of the final products that will be available for sale for the initial 6 years of mining. This will allow for a proactive marketing effort to return the best economic outcomes from the project.
Future grade control programs and ore reserve updates will occur within 5 years of the commencement of mining. Drilling over the project area was completed by means of AC and hand auger methods. Auger drilling was completed in 2017 along existing tracks, with drill spacing of 400 m (east) by 1,000 m (north) along the section lines.
AC drilling was completed in two stages using a Landcruiser mounted drill rig. Stage 1 drilling was completed in 2019, with holes located on the auger drilling tracks as well as along new section lines, forming an overall nominal 400 m section line spacing with drill holes nominally spaced at 400 m (east) by 400 m (north) over the majority of the modelled area. Stage 2 drilling, also referred to as grade control drilling, was completed in March 2021, with 130 holes drilled for 1,459.1 m. Drilling was completed on a drillhole spacing of 50 m (east) by 100 m (north).
AC drilling hole depths range between 3 m and 21 m with an average depth of 10.9 m. All holes were drilled vertically. The 100 mm screw auger drilling samples were taken from 1 m down hole intervals. The sample was sufficiently moist to allow it to cling to the auger screw, with care taken during screw extraction to prevent sample disaggregating from the screw and falling back into the hole.
At the end of each 1 m sample run, the screw was removed from the hole and the sand sample deposited into a plastic tub. The samples typically weighed 8 kg. AC drilling samples are 1 m down hole intervals with sand collected from a cyclone mounted rotary cone splitter, and approximately 2-3kg (representing 50% of the drilled sand) was collected.
Two sub-samples, A and B, of approximately 200 g were taken from the drill samples. Samples were bagged and ticketed with sample numbers prior to transport to the analytical laboratory.
