storage with some pillar removal with the depth of cover varying from 90 to 140 m. Water flowed into the mine workings to a maximum flow rate of 100 000 L/hr. This gradually declined to 30 000 L/h. The proximity of Avon Reservoir and the commonality of algal species between the mine water inflow and the Avon Reservoir suggested a surface to seam connection (Whitfield & Anderson 1988). This inflow resulted in the reduction and eventual curtailment of mining in this area of Wongawilli Colliery (Whitfield & Anderson 1988). Drillhole Extensive Surface Evidence that periodic erosion of Drillhole No baseline monitoring of No known Gully still exists, Swamp gully erosion disturbance Swamp is a naturally occurring process swamp prior to mining. remediation. but has been (Flying Fox within due to mining that predates mining (Tompkins & prevented from Investigations into cause Creek, Avon swamp. investigations Humphreys 2006). travelling deeper following erosion by Catchment) created a by a natural Cracking and History of bord and pillar mining (1968 to Young (1982), EarthTech knick-point, bedrock control. loss of 1969) and longwall mining (1974 to 1977). (2003), and Tompkins & which eroded surface water Humphreys (2006). Cracking and lack Subsidence related cracking and loss of the swamp flow in creek of surface flow is flow from reported in 1971 (ACARP during a downstream. still evident in 2001). subsequent Flying Fox Creek Mining investigations during 1976 including rainfall event. downstream from track construction, building of a small dam, the swamp. removal of vegetation to bedrock and No natural drilling operations, caused surface remediation is disturbance of the swamp creating a
storage with some pillar removal with the depth of cover varying from 90 to 140 m. Water flowed into the mine workings to a maximum flow rate of 100 000 L/hr. This gradually declined to 30 000 L/h. The proximity of Avon Reservoir and the commonality of algal species between the mine water inflow and the Avon Reservoir suggested a surface to seam connection (Whitfield & Anderson 1988). This inflow resulted in the reduction and eventual curtailment of mining in this area of Wongawilli Colliery (Whitfield & Anderson 1988). Drillhole Swamp (Flying Fox Creek, Avon Catchment) Extensive gully erosion within swamp. Cracking and loss of surface water flow in creek downstream. Surface disturbance due to mining investigations created a knick-point, which eroded the swamp during a subsequent rainfall event. Evidence that periodic erosion of Drillhole Swamp is a naturally occurring process that predates mining (Tompkins & Humphreys 2006). History of bord and pillar mining (1968 to 1969) and longwall mining (1974 to 1977). Subsidence related cracking and loss of flow from reported in 1971 (ACARP 2001). Mining investigations during 1976 including track construction, building of a small dam, removal of vegetation to bedrock and drilling operations, caused surface disturbance of the swamp creating a No baseline monitoring of swamp prior to mining. Investigations into cause following erosion by Young (1982), EarthTech (2003), and Tompkins & Humphreys (2006). No known remediation. Gully still exists, but has been prevented from travelling deeper by a natural bedrock control. Cracking and lack of surface flow is still evident in Flying Fox Creek downstream from the swamp. No natural remediation is