The Navajo Tribal Coal Lease is located on the western flank of the San Juan Structural Basin in northwestern San Juan County approximately 15 miles southwest of Farmington, New Mexico. This basin is an asymmetric, structural basin with a northwest trending axis parallel to the Hogback Monocline in northwest New Mexico. The basin is bounded on the northwest by the Hogback Monocline and on the north by the San Juan Uplift. The eastern rim is formed by the Brazos Uplift and the Nacimiento Uplift. The Zuni Uplift and the Chaco Slope form the southern margin of the basin while the Defiance Uplift and Four Corners Platform complete the northwestern basin rim. The San Juan Watershed lies on the eastern edge of the Colorado Plateau and extends from northwestern New Mexico into portions of northeastern Arizona along the New Mexico/Arizona border, southwestern Colorado, and the southeastern most corner of Utah. The San Juan Watershed is approximately 140 miles wide by 200 miles Jong, and covers a total area of 21,600 square miles (URS 2009).

The rock strata in the southern part of the lease area strike north-south while the strata in the northern part strike northeast-southwest. The geologic formation dips gently to the east toward the center of the San Juan Basin at an angle of one to two degrees, and steepens toward the outcrop areas where the fairly abrupt monocline (Hogback) can be observed.

The stratigraphic section in the lease area reflects the Late Creta ........

The Navajo Mine - dragline operation with 2 draglines.

Dragline stripping is the primary mining method used for multiple seam mining operations at the Navajo Mine. The typical sequence for multiple seam mining is as follows:
1. Vegetation and topdressing removal;
2. Overburden drilling and blasting;
3. Overburden removal;
4. Coal drilling and blasting;
5. Coal removal;
6. Interburden drilling and blasting;
7. Interburden removal;
8. Repeat steps 5 through 7 for each minable seam.

The coal seams at the Navajo Mine are exposed in pits that range in width depending on the size of the dragline equipment that is being used to expose them. Pit depths range from 5 to 240 feet, and pit lengths range from 1,000 to 15,000 feet.

Overburden Drilling and Blasting
After all suitable topdressing material is removed, rotary drills are used to drill overburden blast holes. Blast-hole diameters range from 5 to 10 5/8 inches. Blast holes typically are drilled to the top of the coal seam that is being uncovered (until coal is encountered) and then backfilled with 1 to 10 feet of drill-hole cuttings to prevent coal shattering and any accompanying coal loss during blasting. However, some holes may be drilled to a specified elevation of 3 to 7 feet above the coal seam and not backfilled to reduce coal loss due to the movement of the overburden over the coal seam.

Once a set of blast holes has been dr ........

The coal preparation plant is a stacking and reclaiming facility and not a coal cleaning operation.

Coal delivered by railcar (or occasionally by haul trucks) to the preparation plant located in Area I is unloaded into one of two stations into underground hoppers. Fully enclosed feeder systems transfer the coal from the hoppers via electric conveyors into redundant systems consisting of enclosed single-roll crushers, coal quality samplers and scales. The coal is crushed to a ¾-inch to 1-inch diameter suitable for the Four Corners Power Plant (FCPP) pulverizing mills. Hoppers and feeders are equipped with water spray systems, and a mixture of foam and binder is added at the crushers for dust suppression.

Once the coal has been crushed and passed through the sampling towers, it is delivered to the coal stackers via an interconnected electric conveyor and flop gate system. The coal stackers place the coal into one of 10 stacker piles. The coal is stacked in layers ........