Waste from Mineral Processing
Going Beyond the Mine
The minerals we extract from rock occur in very low concentrations, so mining involves moving and processing large amounts of rock. We are responsible for managing this displaced rock in a safe manner.
Management of the displaced rock is accomplished by two primary methods: placement of coarse rock into waste rock dumps and placement of fine-grained rock known as tailing into tailing storage facilities. Potential risks associated with the tailing storage facilities we use include overflow, groundwater contamination from seepage and accidental ruptures. Often, we store this tailing material in specially engineered facilities that are ultimately covered with soil and native plants to minimize water infiltration and re-establish a beneficial land use.
Management of the displaced rock is accomplished by two primary methods: placement of coarse rock into waste rock dumps and placement of fine-grained rock known as tailing into tailing storage facilities. Potential risks associated with the tailing storage facilities we use include overflow, groundwater contamination from seepage and accidental ruptures. Often, we store this tailing material in specially engineered facilities that are ultimately covered with soil and native plants to minimize water infiltration and re-establish a beneficial land use.
How We Engage
Newmont's global environmental standards promote effective structural design and management of waste rock and tailing facilities. To enhance the protective capacity of our modern tailing facilities, they are lined to prevent leaks and equipped with complex systems for seepage recovery if they do leak.
Newmont believes that we have constructed the first tailing facilities that have fully synthetic-lined containment beneath the facility pond area in both Ghana and Australia, where neither country's laws or regulations required this level of protection. We also strive to incorporate closure considerations in the design of waste rock and tailing facilities so they can be decommissioned to support productive post-closure land use.
How The Process Works
We extract gold from ore by crushing it to the consistency of sand (milling), adding water to form a slurry, and then mixing it with a weak cyanide solution. Gold particles bond with the cyanide in the solution. After the gold is extracted from the slurry, the crushed rock that is left is called tailing. The tailing slurry is then pumped to a tailings storage facility (TSF), which is designed for safe, long-term storage and eventual closure with controls to manage any potential seepage from these facilities. As the tailing solids settle out in the TSF, the solution is collected on top of the facility and is recycled back to the mill to be used for further processing.
At Newmont's operations in Indonesia, storing tailing on land was not feasible because of heavy rainfall, risk of earthquakes and a shortage of land that wouldn't disrupt farming. Because of this, government regulators deemed it preferable to place the tailing offshore on the seafloor. This practice is known as subsea tailing placement. In 2007, the Batu Hijau project perfected an innovative technology, called a "smart pig," to monitor performance of the tailing conveyance system.
Snapshot: Innovative Technology Verifies Integrity of Undersea Pipeline
Snapshot: Modern Tailings Management in Yanacocha
Low-grade ore is treated differently because of the high cost of milling. This material is placed in layers on an engineered, compacted clay liner with a high-density polyethylene liner cover. This is called a leach pad. Water containing very low concentrations of cyanide is dripped onto the leach pad to extract the gold from the rock. The solution collected at the lined base of the facility flows to double- or triple-lined ponds for processing. Leach pads are specially designed and constructed to ensure the solution is contained to prevent any leakage into groundwater and surface water.
Newmont believes that we have constructed the first tailing facilities that have fully synthetic-lined containment beneath the facility pond area in both Ghana and Australia, where neither country's laws or regulations required this level of protection. We also strive to incorporate closure considerations in the design of waste rock and tailing facilities so they can be decommissioned to support productive post-closure land use.
How The Process Works
We extract gold from ore by crushing it to the consistency of sand (milling), adding water to form a slurry, and then mixing it with a weak cyanide solution. Gold particles bond with the cyanide in the solution. After the gold is extracted from the slurry, the crushed rock that is left is called tailing. The tailing slurry is then pumped to a tailings storage facility (TSF), which is designed for safe, long-term storage and eventual closure with controls to manage any potential seepage from these facilities. As the tailing solids settle out in the TSF, the solution is collected on top of the facility and is recycled back to the mill to be used for further processing.
At Newmont's operations in Indonesia, storing tailing on land was not feasible because of heavy rainfall, risk of earthquakes and a shortage of land that wouldn't disrupt farming. Because of this, government regulators deemed it preferable to place the tailing offshore on the seafloor. This practice is known as subsea tailing placement. In 2007, the Batu Hijau project perfected an innovative technology, called a "smart pig," to monitor performance of the tailing conveyance system.
Snapshot: Innovative Technology Verifies Integrity of Undersea Pipeline
Snapshot: Modern Tailings Management in Yanacocha
Low-grade ore is treated differently because of the high cost of milling. This material is placed in layers on an engineered, compacted clay liner with a high-density polyethylene liner cover. This is called a leach pad. Water containing very low concentrations of cyanide is dripped onto the leach pad to extract the gold from the rock. The solution collected at the lined base of the facility flows to double- or triple-lined ponds for processing. Leach pads are specially designed and constructed to ensure the solution is contained to prevent any leakage into groundwater and surface water.
What's Next?
In 2010 Newmont worked to complete the final engineering studies for our second project in Ghana at Akyem. The Akyem Project will likely start construction in 2011 and will have the second fully lined tailing facility in Ghana.
2010 Overview
In 2010, we moved 660.99 million tonnes of rock. Mining involves moving and processing large amounts of rock. Of the total material mined, about 455.81 million tonnes of this was set aside because it contained no valuable metals. See 2010 pie graph for ore/waste percentages.
