Spring Creek

Overview

Spring Creek Mine is located in southeast Montana near the town of Decker, in the northwest section of the Powder River Basin. The mine was acquired by Rio Tinto Energy America in 1993 and previously owned by NERCO Mining Company, a mining and natural resource company of PacifiCorp.

Spring Creek mines the Anderson-Dietz seam, which has an average thickness of 80 feet. The typical average quality of the coal is 9,350 Btu subbituminous thermal coal.

Spring Creek Mine utilizes a highly efficient combination of dragline open-pit operations with truck-shovel assist to produce significant volumes of coal each year.  In 2010, Spring Creek mined and shipped approximately 19.3 million tons of coal.

Spring Creek Mine is permitted for 24 million tons of coal a year. Coal mined from Spring Creek is sold to electric utilities and industrial customers in the northwest, midwest, northeast and southwest United States, various Canadian provinces and exported to Asian utility customers via the Westshore Terminal in Vancouver, Canada. At year-end 2010, Spring Creek Mine employed 232 full-time employees.

In 2005 and again in 2009 Spring Creek Mine received the Excellence in Surface Mining and Reclamation Award from the Office of Surface Mining. These awards recognized significant achievements in developing reclamation with hydrologic and biologic diversity and for intensive effort in establishing rare plants on reclamation.

Location

Spring Creek Mine is located in Big Horn County,  southeast Montana, USA, near the town of Decker, in the northwest section of the Powder River Basin. 

Montana is a state in the western United States.  The economy is primarily based on services, with ranching, wheat farming, oil and coal mining in the east, and lumber, tourism, and hard rock mining in the west. 

The Powder River Basin is a geologic region in southeast Montana and northeast Wyoming, about 120 miles (190 km) east to west and 200 miles (320 km) north to south, known for its coal deposits. The region supplies about 40 percent of coal in the United States.  It is both a topographic drainage and geologic structural basin. The basin is so named because it is drained by the Powder River.

Geology & Mineralization

The coal beds of the region began to form about 60 million years ago when the land began rising from a shallow sea. The rise of the Black Hills uplift on the east and the Hartville uplift on the southeast side of the basin created the present outline of the Powder River Basin.

When the coal beds were forming, the climate in the area was subtropical, averaging about 120 inches (3,048.00 mm) of rainfall a year. For some 25 million years, the basin floor was covered with lakes and swamps. Because of the large area of the swamps, the organic material accumulated into peat bogs instead of being washed to the sea. Periodically the layers of peat were covered with sediments washed in from nearby mountains. Eventually the climate became drier and cooler. The basin filled with sediment and buried the peat under thousands of feet, compressing the layers of peat and forming coal. Over the last several million years, much of the overlying sediment has eroded away, leaving the coal seams near the surface.

Sub-bituminous coal from the Powder River Basin (PRB) is used primarily by electric utilities and by some industrial customers for steam generation.

PRB coal typically has lower sulfur content than eastern U.S. coal and generally emits no greater than 0.8 pounds of sulfur dioxide per million Btus. Company’s coal reserves are compliance coal under the Clean Air Act. Some customers ask that Spring Creek coal is mixed with earthen materials as to dilute the sodium oxide content of the post-combustion ash of the coal. The low chlorine of the coal is somehow offset by the presence of mercury which is difficult to remove with conventional pollution control devices.

Spring Creek thermal coal has 9,237 Btu per lb, 5.13% ash content, and 0.32% sulphur content.

Mining & Operation

Surface mining typically involves the removal of topsoil, and drilling and blasting the overburden (earth and rock covering the coal) with explosives. The overburden is then removed with draglines, trucks, shovels and dozers. Trucks and shovels then remove the coal. The mine typically recovers 92% or more of the economic coal seam. 

The final step involves replacing the overburden and topsoil after the coal has been excavated, reestablishing vegetation and plant life into the natural habitat and making other changes designed to provide local community benefits. 

In 2011, the mine produced 17.19 million tonnes of thermal coal.  Total proven and probable reserves stood at 311 million tonnes. Contiguous to or near primary reserves base coal deposits contained 26.1 million tonnes coal.

Processing

Depending on coal quality and customer requirements, in almost all cases the coal from our mines is crushed and shipped directly from our mines to the customer. However, depending on the specific quality characteristics of the coal and the needs of the customer, blending different types of coals may be required at the customer’s plant. Coals of various sulfur and ash contents can be mixed or ‘‘blended’’ to meet the specific combustion and environmental needs of customers. All of our coal can be blended with coal from other coal producers.

Spring Creek’s location and the high Btu content of its coal make its coal suited for export and transportation to the northeastern U.S. coal markets for blending by the customer with coal sourced from other markets to achieve a suitable overall product.

The Spring Creek mine is served solely by the BNSF railroad. In 2011, Spring Creek shipped approximately 4.5 million tons of Spring Creek coal through terminals located in British Columbia, Canada. During the same year the company entered into a long-term throughput contract with Westshore Terminals Limited Partnership that expires in 2023.

Environment & Community

Respect for the environment is central to the company's approach to sustainable development. Wherever possible the company prevents, or otherwise minimize, mitigate and remediate, harmful effects of the Group's operations on the environment.