permanent activity (BHP Billiton 2003). and quality monitoring reportedly onsold pools. conducted prior to Elouera mine and Impacts include: loss of flow from creek extraction of Longwall 7. remediation of Toxic levels and altered water chemistry with toxic impacts uncertain. of pH and levels of aluminium, zinc and nickel Environmental Monitoring heavy metals detected along with lowered pH at one site Program by mining identified at (BHP Billiton 2003). company implemented for one site. extractions of Longwalls 7 and beyond. Bargo River Cracking of Subsidence The first longwalls to mine directly beneath Little baseline data No known The most recent bedrock and related to the Bargo River commenced in 1991 collected. remediation of longwall proposal loss of longwall (Longwalls 8 to 13). Bargo River. for Tahmoor Some monitoring at surface flow extraction. Colliery appear to Surface fracturing with cracks up to 50 mm various stages by mining Two agricultural including loss have deliberately wide were observed near the supporting company - see MSEC bores replaced of water from avoided impacts piers of Rockford Rd Bridge following the (2006) and Geoterra while one had a permanent on the Bargo extraction of Longwalls 12 and 13 (MSEC (2006). temporary water pools. River by not 2006 and Geoterra 2006). supply from a Further fracturing of mining Declines in truck as Fractures were also observed during bedrock in Bargo River underneath the groundwater required. extraction of Longwall 12 downstream of that might occur as a river and by levels. the bridge (MSEC 2006; Holla & Barclay result of the extraction of staying a distance 2000). the proposed longwalls is of at least 225 m assessed as very minor The second series of longwalls to mine (MSEC 2006). since Longwalls 24 to 26 directly beneath the Bargo River Nevertheless it is do not mine directly commenced in 1995 (Longwalls 14 to 19). predicted that the beneath the river. Limited monitoring indicated little impact on River may the River during the extraction of Longwalls crack at the main 14 to 17. Fracturing was not visible on the arm bend of the surface, although many sections were river due to uplift concealed by alluvial and talus deposits. of up to 142 mm
permanent pools. Toxic levels of pH and heavy metals identified at one site. activity (BHP Billiton 2003). Impacts include: loss of flow from creek and altered water chemistry with toxic levels of aluminium, zinc and nickel detected along with lowered pH at one site (BHP Billiton 2003). and quality monitoring conducted prior to extraction of Longwall 7. Environmental Monitoring Program by mining company implemented for extractions of Longwalls 7 and beyond. reportedly onsold Elouera mine and remediation of impacts uncertain. Bargo River Cracking of bedrock and loss of surface flow including loss of water from permanent pools. Declines in groundwater levels. Subsidence related to longwall extraction. The first longwalls to mine directly beneath the Bargo River commenced in 1991 (Longwalls 8 to 13). Surface fracturing with cracks up to 50 mm wide were observed near the supporting piers of Rockford Rd Bridge following the extraction of Longwalls 12 and 13 (MSEC 2006 and Geoterra 2006). Fractures were also observed during extraction of Longwall 12 downstream of the bridge (MSEC 2006; Holla & Barclay 2000). The second series of longwalls to mine directly beneath the Bargo River commenced in 1995 (Longwalls 14 to 19). Limited monitoring indicated little impact on the River during the extraction of Longwalls 14 to 17. Fracturing was not visible on the surface, although many sections were concealed by alluvial and talus deposits. Little baseline data collected. Some monitoring at various stages by mining company - see MSEC (2006) and Geoterra (2006). Further fracturing of bedrock in Bargo River that might occur as a result of the extraction of the proposed longwalls is assessed as very minor since Longwalls 24 to 26 do not mine directly beneath the river. No known remediation of Bargo River. Two agricultural bores replaced while one had a temporary water supply from a truck as required. The most recent longwall proposal for Tahmoor Colliery appear to have deliberately avoided impacts on the Bargo River by not mining underneath the river and by staying a distance of at least 225 m (MSEC 2006). Nevertheless it is predicted that the River may crack at the main arm bend of the river due to uplift of up to 142 mm