1.2.1.1.3 Western Coalfield

Illawarra Coal Measures

Western Coalfield coals are mainly bituminous thermal coals with medium to high ash and low sulfur. Most of the coal is produced from three main economic units within the Illawarra Coal Measures: the Lithgow Coal, Ulan Coal, and the Katoomba Coal Member (Yoo et al., 2001, p. 87).

The Lithgow Coal contains economic resources between Lithgow and Rylstone and in the Bylong area. In the Lithgow area it ranges from 1.5 to 4.6 m in thickness, has an ash yield of between 14 and 35%, and is medium to high volatile coal which is low in sulfur (Yoo et al., 2001, p. 87). The Lidsdale Coal has a thickness of up to 2 m, with a raw ash yield of about 30% (Yoo et al., 2001, p. 88). The Ulan Coal is a 14 m thick coal-bearing unit best developed in the Ulan and Wilpinjong area. It is divided into upper and lower sections by a 0.3 m thick tuffaceous claystone. In the Ulan area, the lower section (known as the D working section, or DWS) ply is approximately 3 m thick and has an average raw ash yield of 11 to 13% (air dried). In comparison, the upper section is about7 m thick and has an ash yield of up to 45%. In the Wilpinjong area, the upper section of the Ulan Coal ranges in thickness from 1.4 to 3.5 m, with an ash yield range of 14.5 to 30.7% (Yoo et al., 2001, p. 89). At Moolarben Coal Mine, the Ulan seam has a mean thickness of approximately 12 m throughout the deposit (Yancoal, 2015b). Only the lowest 3 m of the Ulan Coal is mined at the Ulan Mine. Due to the coal’s particularly high quality only about 30% of the coal requires washing (Ulan Coal, 2015). The coal is of high quality with low sulfur, nitrogen and phosphorous, providing good handling and combustion properties (Ulan Coal, 2015).

The Irondale Coal has some economic potential at Running Stream, and north of the Wilpinjong and Moolarben area, where it is up to 2 m thick with an ash yield of 10.6% (Yoo et al., 2001, p. 90). In the area north of Ulan, the Moolarben Coal Member ranges in thickness from 1.76 to 2.72 m with an ash yield for selected sections of 27 to 34%. The seam is potentially mineable in the Cockabutta Creek area and the area around Moolarben (Yoo et al., 2001, p. 90). In the northern part of the Western Coalfield the Turill Coal Member is 3.5 to 4 m thick at 210 to 600 m depth, consisting mainly of dull coal with common bright layers. The ash yield of the seam ranges from 23 to 45% (Yoo et al., 2001, p. 91). The Middle River Coal Member is a 12 to 20 m thick interbedded unit with a high proportion of tuff, claystone, carbonaceous claystone and coal. Ash yields of selected sections are, on average, around 26% (Yoo et al., 2001, p. 91).

The Katoomba Coal Member has been mined to produce coal for thermal use and is a medium-volatile, low-sulfur steaming coal, mostly 1.5 to 3.0 m thick, with an ash yield between 11 and 23%. It occurs east of Rylstone but its economic distribution has been affected by erosion prior to deposition of sandstone and conglomerate units of Narrabeen Group. It contains a high proportion of claystone layers and has poor beneficiation characteristics (Yoo et al., 2001, p. 91).

According to Hutton (2009, p. 43) there is little possibility of economic seams in the Yarrunga Coal Measures and the Clyde Coal Measures of the Shoalhaven Group, since the seams are discontinuous and thin. Furthermore, there is little information available on the character and distribution of these coal measure sequences in the Hunter subregion.