Mining at Holt is primarily conducted using Long Hole Stoping with cemented rock fill. A 1.2 km deep shaft provides skipping capacity of 1,500 tpd. Currently, approximately 85% of the mining activities takes place in Zone 4 and 6, with development towards Zone 7, in anticipation of starting production in 2018. Ore hoisted from the Holt Mine is conveyed directly to the Holt Mill via a series of 1,000 to 3,000 storage bins.
The Holt Mill is one of the most efficient gold mills in the region with a capacity of 3,000 tpd, of which approximately 1,300 tpd are supplied from Holt Mine and a little under 600 tpd from the Taylor Mine, representing a 60% utilization rate.
The Holt Mill was constructed in 1988, originally designed for a throughput of 1,360 tpd. Expansions in 1988 and 2001 increased the throughput to 2,500 tpd and 3,000 tpd respectively.
Surface ore storage totals 4,900 tonnes in three silos. There is a grinding circuit, two cyclone cluster circuits, a thickener, and a Carbon-in-Leach (CIL) circuit within the plant facilities.
Precious metal stripping is performed in batch. Carbon is transferred to an adsorption column where a Zadra process is utilized as the gold elution method. Barren solution is circulated through two shell and tube heat exchangers and a 360 kW electric inline heater. The resulting pregnant solution is pumped from the solution tank to an electrowinning cell. The gold precipitate is further refined using a 125 kW inductotherm furnace.