The No 1 Seam averages 2.0 to 2.5 m in thickness and is generally of good quality, able to produce a steam coal of 27.40 MJ/kg at yields greater than 60%. The Number 1 Seam Roof (S1R) coal is of lower grade with lower yields and is only mined when the No 1 Seam is destined for the local power station market. In places, the seam may be too thin to mine.

The P1 parting between the No 2 and No 1 Seams is between 1.5 and 4.0 m thick and consists of sandstone. The No 2 Seam is developed over almost the entire Bokgoni area, subcropping to the north of the Bokgoni Pit. The seam varies in thickness from five to eight metres, averaging six metres. The seam is subdivided into subseams, generally based on quality. The highest quality coal occurs in the middle of the seam (the S2S), with duller coal above and below it.

The No 3 Seam, although of good quality, is thin (approximately 30 cm) and has not been mined; it is used as a marker horizon. The quality of the No 4 Seam is highly variable across Bokgoni, with poorer quality coal in the west where the P4L parting occurs. The thin, upper portion of the seam (the S4) is of a higher quality, while the lower split below the parting, is of poorer quality. Higher grade coal is found in the east. The average seam thickness is 2.2 m.

The No 5 Seam is on average, 1.5 m thick and is found in the deeper areas of Bokgoni.

The Bokgoni Pit was placed on care and maintenance in December 2020 due to the prevailing economic conditions; as such, no Coal Reserves have been declared as a new mine plan would need to be developed by the Company in order to extract any future coal, should economic conditions improve sufficiently.

Although the Bokgoni 2A pit was put on care and maintenance, small scale, truck and shovel mining of 0.4 Mt, has occurred from No 5 and 4 Seam inventory coal during 2021 taking advantage of the favourable market conditions.

Each tip has grizzlies with 750 mm x750 mm apertures onto which coal is tipped by trucks. The coal passes through the grizzlies into the RoM bins, each of which has a 1 200 t capacity. Below each of the RoM bins are feeders which feed raw coal into their respective rotary breakers. The rotary breaker picks the coal up four to five times, the coal preferentially breaks and falls through 150 mm diameter holes. Numerous magnets are positioned to attempt to remove some of the extraneous metal in the feed. Some material will not break, passes through the breaker and is rejected.

From Tip B (and previously Tip A), the reject from the rotary breakers passes to the W1 Conveyor and into a stone bin. This waste is taken back to the mine by trucks loaded from the stone bin. The coal from the Tip C bin is also fed onto a vibrating grizzly cutting at 150 mm, with the +150 mm material being fed into the rotary breaker.

In the past, the rotary breaker reject was fed into a jaw breaker to reduce all the material to -150 mm as the roof coal and the discard material is considerably harder and potentially contains more of the lower grade product coal for which it will be washed. The crushed oversize material is then combined with the rotary breaker underflow. However, this has now been changed and the jaw crusher has been taken out of circuit. The circuit is now essentially the same as Tip B, with the waste rejected from the rotary breaker joining the waste from Tip B.

The Kleinkopje CHPP, now the Bokgoni CHPP, is one of the original plants in the submission to the Japanese steel mills to produce low ash coal.

The plant still treats two types of coal, except that the qualities from each stream are now very different to the original products for which the plant was designed. Originally No 2 Seam coal was used to produce the LAC product and a combination of No 2 and No 4 Seam coal was used to produce a steam coal. The feed coal is now from a combination of sources to constitute the export product and a No 4 Seam Upper coal, known as “Roof”, to produce a lower grade middling coal. Middling coal is also made using nearby discard sources.

The plant has now been substantially separated into two sections:
• The Export Plant, which can be fed with export or roof feed coal, and
• The Roof Plant, which can be fed with roof coal or discard coal.

Coal is produced from an opencast operation and a discard dump. The coal ........