De Grey unearths deep extension to Toweranna mineralisation
Special Report: An ongoing drilling program continues to rack up the high-grade gold hits at De Grey Mining’s multi-million ounce Pilbara project.
Deep drilling below the existing Toweranna open pit resource intersected multiple stacked veins hosting high-grade gold, while shallow drilling outside the existing resource also returned some intriguing hits.
“A threefold extension to mineralisation at depth within the intrusion and adjacent sediments with multiple stacked high-grade veins is particularly encouraging,” De Grey technical director Andy Beckwith said.
“All the diamond drilling results are outside of the existing resource and demonstrate high grade mineralisation continue at depth and remain open.
“The new shallow RC drilling results are also outside of the existing resource and provide a new structural control to the NE along strike from the main intrusion.”
The numbers certainly paint a pretty picture. Drilling between 200m and 400m depth returned high-grade results including 4.34m at 8.3 grams per tonne gold, while deeper drilling shows that the gold mineralisation occurs to a depth of at least 600m.
Anything above 5g/t is generally considered high grade.
Meanwhile, shallow drilling to the northeast of the existing open pit resource returned results like 3m at 7.2g/t gold from a depth of 167m.
The Toweranna deposit currently has an open pit resource of 5.33 million tonnes at 2.1g/t gold for 356,600 ounces of contained gold.
De Grey have previously provided an exploration target to 400M of 680,000 to 800,000 ounces. With 350,000 ounces to 200m already in the “bank” recent results would indicate that the Exploration target is well on its way to being reached, if not surpassed.
Metallurgical studies have confirmed that ore from the deposit is free milling and fully amenable to conventional, low-cost carbon-in-leach (CIL) processing.
Looking ahead, the company will continue resource extension drilling programs at the Withnell and Mallina deposits.
De Grey also highlighted that the planned ore sorting evaluation of vein and waste separation and grade distribution will be carried out on diamond core from three purpose drilled holes within the existing resource area, in addition to a coarse crushing evaluation (20-100mm) on ~4 tonnes of oxide and fresh material.