Real World Improvement through Virtual Instrumentation at Oceanagold Haile

"The Haile gold mine in South Carolina is increasing the automation level of its processing plant in order to improve operational stability. One step toward this goal is the application of a digital twin concept to provide virtual instruments. Haile has engaged Andritz to implement virtual instruments at its grinding area hydrocyclones and at its tailing thickener underflow pump. These virtual instruments provide density values in a traditionally difficult location for reliable slurry density measurement. The digital twin is a first-principles integrated design engineering with advanced simulation (IDEAS) simulation model, connected in real time to the control system. Results have been promising, with the virtual instrument values matching the physical instrument under normal operating conditions and showing better prediction under upset conditions. Haile plans to use the virtual instruments as optional process control parameters.OceanaGold’s Haile gold mine is located near Kershaw, SC, about 80 km (50 miles) southeast of Charlotte, NC. This location was first mined in 1827 and has produced gold through several operating periods since then, including a heap leaching operation from 1985 through 1992. In October 2015, OceanaGold acquired Romarco Minerals, the previous owner of the Haile operation.The current operation began in 2017 as an openpit mine with additional underground resources. The nameplate throughput is 5,760 t/d (6,350 stpd) ore, and 2017 production was 3,345 kg (118,000 oz) gold, with 3,968 to 4,384 kg (140,000 to 155,000 oz) gold expected in 2018. Proven and probable reserves exceed 85 t (3 million oz) gold at a grade of 2 g/t (0.06 oz/st) gold. The process, as shown in Fig. 1, includes a primary jaw crusher, comminution with a semiautogonous grinding (SAG) mill and ball mill circuit, flash flotation, rougher flotation, regrinding, pre-aeration, carbon-inleach leaching, carbon elution and regeneration, cyanide recovery, electrowinning and refining. The Haile operation’s inaugural gold pour took place Jan. 20, 2017. Mine life is expected through the year 2030."