Greenhills operation is located 8 kilometres northeast of Elkford. At Greenhills, up to 24 coal seams occur in the Jurassic-Cretaceous Mist Mountain Formation (Kootenay Group) interbedded with sandstone, siltstone and shale. The major seams, which are continuous throughout the area, are named 1, 7, 10, 16 and 20. Seams 1, 7 and 10 (68 per cent of in place geological reserves) are medium volatile bituminous coal, while seam 16 and other stratigraphically higher seams are high volatile A bituminous in rank. Other major seams are lenticular and less extensive (several kilometres extent) and occur generally in the upper half of the Mist Mountain Formation. Thicknesses of the major seams are as follows from oldest to youngest; seam 1 (10 to 16 metres), 7 (7 to 11 metres), 10 and 10L (5 to 11 metres), 16 and 16L (5 to 11 metres, and seam 20 (2 to 7 metres).

The main structure in the Greenhills area is a broad, open, roughly north trending, gently north plunging syncline. Beds on the west limb dip 20 to 40 degrees east and on the east limb 20 to 60 degrees west. The east limb is cut off to the east by a major normal fault (north extension of the Fording River fault), whose local vertical displacement is greater than 600 metres. The west limb of the syncline is cut by some minor thrust faults. Three kilometres south of the Kaiser Resources north boundary, the Greenhills normal fault splays off the Fording River fault. The former has a 120 to 140 metre displacement (west side downthrown).

Westar Mining Ltd. started operations in 1981, production in 1982, and shut down in December 1992. Fording Coal Ltd. re-opened the mine in March 1993. It has been in continual production since then, and produced over 148 million tonnes of coal between 1981 and the end of 2019.

In 2015, a drilling exploration program by Teck Resources Limited totalled 294,000 metres between 3,500 holes (Knight, A., Mills, D., Seward, A. (2016-01-27): NI 43-101 Technical Report on the Mineral Resource and Mineral Reserve Estimates for the Greenhills Operation).

As of 2019, Teck (80 percent ownership) and POSCAN (20 percent ownership) continue to produce hard coking coal, pulverized coal injection, and thermal coal from the Greenhills Operations. With an annual production of over 6 million tonnes of coal, the mine life from the current pits is 28 years.

Reserves at Greenhills as of December 31, 2019 are 11.6 million tonnes proven, plus 283.4 million tonnes probable, of clean coal. Measured and Indicated Resources as of the same date total 407.1 million tonnes. (Teck Annual Information Form 2020 https://www.teck.com/media/2020-AIF.pdf).

The Cougar North Extension, a proposed expansion of the Cougar pit, has undergone intermittent rotary and diamond exploratory drilling since 2008. The Cougar North Extension has similar coal characteristics to the current Cougar pit, and at full development, is planned to merge with the Fording River Swift expansion project (Information Circular 2016-1).

At the Green Hills occurrence, total historical exploration includes 34 adits, 196 trenches, and 76 outcrops mapped (Knight, A., Mills, D., Seward, A. (2016-01-27): NI 43-101 Technical Report on the Mineral Resource and Mineral Reserve Estimates for the Greenhills Operation).

In 2020, Teck Resources Ltd. reported an updated coal resource for the Cougar and Crow Ridge (MINFILE 082JSE005) deposits with a total of 407 001 000 tonnes of measured and indicated raw coal with an additional 168 540 000 tonnes of indicated raw coal (Mills, D.E., Knight, A.J. [2020-02-20]: NI 43-101 Technical Report on Greenhills Coal Operation, British Columbia, Canada).