JOHANNESBURG (miningweekly.com) – Dual-listed Orion Minerals has initiated investigations into the early mining of potentially significant remnant zinc/copper mineralisation within accessible areas of existing mine infrastructure of the historic Prieska mine, in the Northern Cape.

Orion is evaluating potential sulphide mineralisation above the water level, which could present a potential upside source of valuable early cash flow to be considered in the bankable feasibility study (BFS) that is currently under way.

“As a first stage in this investigation, historic mine plans and longitudinal sections are being used to identify and calculate the tonnage potential of intact mineralisation. This will be followed up by underground verification, geotechnical appraisal and drill planning for underground drill testing,” Orion CEO and MD Errol Smart said in an update to shareholders on Tuesday.

Orion has located and recovered a large volume of historic hard copy and digital data for the Prieska project from the previous owners.

“The data recovered is thought to include important information, including digital mine planning records, that may assist in mineral resource estimation and evaluation of the new +370 BSC Target,” he said.

Given the new data acquisition and the ongoing positive extensional drilling, the maiden mineral resource estimates for the openpit +105 Level Target and North West Deep Sulphide Target are now scheduled for the first quarter of 2018.

Drilling will continue on strike extensions into 2018, with final BFS mineral resource estimates expected by mid-2018.

Further, recent assay results received provide further encouragement for extensions to thick zones of zinc/copper massive sulphide mineralisation beyond those presented in historic mine planning records at the Prieska project.

“These intersections build on the success of drilling conducted since May 2017 and have validated Orion’s electromagnetic (EM) targeting model, with hole OCOD087 successfully testing a defined target,” Smart commented.

The OCOD087 hole intersects 12.45 m at 5.17% zinc, 1.12% copper, 0.25 g/t gold and 10.8 g/t silver.

A total of 44 intersections have now been completed by Orion at vertical depths of 974 m to 1 193 m below surface, including 11 intersections drilled for the collection of samples for confirmatory metallurgical testwork.

“We continue to be pleased with drilling and exploration results at the Prieska project. While drilling within the confines of historically drilled mineralisation continues to verify the grade and width as historically reported, drilling on strike and dip extensions is intersecting significant extensions to known mineralisation, which has potential to rapidly increase the tonnages to be included in the resource estimate and BFS,” Smart added.

The “most pleasing” of the findings are the assay results from mineralisation associated with electromagnetic conductors, highlighting the potential for modern exploration techniques to make new discoveries both at the Prieska project and in the Areachap belt.

“The rapid deployment for and successful execution of a technically challenging drill programme using cost effective local equipment, contractors and staff, attests to the benefits of operating in a sophisticated mining destination like South Africa,” he concluded.