In the Center Mine the Kinneman Creek (5 feet thick) and Hagel (10 feet thick) beds are the target beds. The Kinneman Creek and Hagel (A and B) coal beds extend throughout much of the central portion of the Oliver county. Fort Union strata is 700 to 1,200 feet thick in this county. Unfortunately, there is little to no subsurface control beyond a depth of about 400 feet in this area.

Before mining begins, a rotary drill is used to define the lignite field, the depth and thickness of lignite seams, and the amount and type of material (or "overburden") overlying the lignite.

The first step in the mining process is the removal of the topsoil and subsoil. The process of removing and respreading topsoil and subsoil is typically done with scrapers.

Overburden removal can begin after topsoil and subsoil have been removed. In areas of thick overburden, a hydraulic excavator and a fleet of end dump trucks are used to remove part of the overburden prior to dragline operations. The excavator and truck overburden removal step was introduced into BNI’s mining process in 2012.

The primary overburden removal tool at the Center Mine is the dragline. These machines can remove overburden up to 120’ thick and place it in piles 140’ high. The buckets of these draglines are larger than a typical school bus. They are powered with electricity produced from the same lignite they uncover.

The final step in the mining process is the removal of the lignite from the pit. This is done with a fleet of bottom dump trucks loaded with a large front end loader. Once loaded, the majority of the lignite is sent directly to the Milton R. Young Stations as fuel for electrical generation. A small amount of lignite is sent to the Center Coal Company where it is sold as a heating fuel. Once the coal is removed from the pit the mining process is compl ........

After the lignite has been uncovered with the dragline, it must be broken into smaller pieces before it can be hauled to the power plant. This operation is done with bulldozers. The bulldozers at BNI are equipped with a large ripper shank built specifically for breaking coal into pieces small enough to be placed into BNI’s haul trucks.