A Sandvik LH 517 LHD, powered by a Volvo Penta Tier 4 Interim-compliant diesel, works underground at the Pogo gold mine southeast of Fairbanks, Alaska.
With 30 miles (18 km) of underground tunnels, Sumitomo’s Pogo mine, located 85 miles southeast of Fairbanks, Alaska, is home to two large high-grade gold-bearing quartz veins that yield more than 2,500 tons of ore each day. In production since 2006, Pogo is one of the state’s top gold mines.
At the mine, a Sandvik LH 517 LHD works two shifts—up to 20 hours each day—loading out of the face and into trucks. The machine was purchased in late 2013 and is equipped with a Volvo Penta Tier 4 Interim TAD1361VE engine, which has since clocked more than 1,800 hours.
The Pogo mine faces several challenges that the Volvo Penta engine has helped to address. In an area where winter temperatures typically hover around -12°F (-24°C) but can plummet to -60°F (-51°C), it’s important to keep the inside of the mine as warm as possible. Ventilation air is heated to 40°F (4°C) year round at significant cost: the Pogo mine is the biggest user of propane in the state of Alaska.
The Volvo engine has lower air exchange requirements than a Tier 2-equipped unit the mine previously used (12,000 CFM versus 26,000 CFM), which has helped Pogo save money on the cost of heating the air while staying within U.S. Mine Safety and Health Administration (MSHA) compliance on air standards and without having to upgrade their ventilation system.
Two years ago, a compliance audit determined that the Pogo mine’s machinery was producing high levels of diesel particulate matter (DPM). The aftertreatment systems on the machines were re-engineered to lower their particulate matter, but then nitrogen oxide (NOx) levels rose. Installing a Volvo Penta Tier 4i TAD1361VE, with its selective catalytic reduction (SCR) technology, has reduced NOx levels by more than half.
“The engine is clean-burning, and with current legislation requirements, that’s critical,” said Paul Brunelle, general foreman of the mine. “Not only that, [the LHD’s] been running well with minimal downtime, and the operators like the ride. It’s our favorite mucker out there.”
Sandvik Mining formally selected Volvo Penta engines for its underground trucks and loaders almost two years ago, announcing the decision in January 2013. At the time, the two OEMs noted that the Volvo Penta engines used in its trucks and loaders met stringent Tier 4i/Stage IIIB emission standards for NOx and DPM. The Volvo Penta exhaust-treatment solution reduces DPM levels without the need for a diesel particulate filter (DPF).
As indicated by the Pogo mine’s experience to date, Volvo Penta is quick to note that its engines are designed to generate less heat than higher-powered engines while doing the same amount of work. Also—because the Tier 4i engines do not utilize cooled EGR—their heat rejection requirements and radiator size are reduced, allowing equipment builders to use the same radiator size as a Tier 2 engine.