In 2022, DA Smith was commissioned by Nevada Gold Mines (NGM) to core drill and measure the in situ pre-mining stress state at the Leeville underground gold mine. NQ wireline core drilling was conducted with a Boart-Longyear LM90 from underground development to locate suitable rock for stress measurements.
Stress measurements were conducted between faults in an argillaceous to limy mudstone approximately 2,000 feet below surface. Stress was measured by overcoring (6-inch-diamter) with CSIRO digital hollow inclusion (HID) cells. Field measurements taken by DA Smith overcoring personnel were transmitted via mine Wi-Fi to DA Smith engineers at company headquarters for real time analysis.
A total of eight stress measurements produced a statistically valid tensor of the three-dimensional stress state satisfying project objectives. The underground program was completed accurately, efficiently, and safely.
NGM is a joint venture between Barrick (61.5%) and Newmont (38.5%) that combined their significant assets across Nevada in 2019 to create the single largest gold-producing complex in the world. Newmont (US) is the largest gold producer in the world, followed by Barrick (Canadian), together producing over 10.7 million ounces of gold in 2021 from NGM and other mines internationally. Leeville is a key underground mine in the NGM Carlin portfolio.