Assessment of horizontal bore drains performance in brown coal mines in the Latrobe Valley
- Authors: Perdigao, Cristhiana
- Date: 2021
- Type: Text , Thesis , Masters
- Full Text:
- Description: Horizontal bores are essential infrastructures for maintaining the stability of open-pit mine batters. The infiltration of water from large surface catchments during rain events and induced deformation caused by mining activities can cause the build-up of pore water pressures in mine batters, potentially leading to catastrophic slope failures. A field investigation unit containing a camera has been developed to survey long (>300m) horizontal bores. Features observed using the camera along the profile of horizontal bores are discussed. Water flow was quantified by flow meters. X-Ray Diffraction (XRD) was undertaken to investigate the water precipitates within the selected bores. Water flow temperature was recorded to test the hypothesis of a possibility to indicate whether a borehole was draining from the saturated zone or from the surface water through its temperature. The investigations have been conducted to determine the cause of change in the efficiency of horizontal boreholes and find a reliable measure to assess longevity and performance of horizontal drains. Bore efficiency has been defined as the bore functioning as a preferential path for water within the batter to be drained out to reduce the saturated zone and associated pore water pressures within the batter. The results suggest blockages and fractures inside the bores can be considered the leading cause of the change in the efficiency of a bore. Blockages occur because of sediment accumulation and because of coal chunks from internal wall collapses. Internal fractures affect efficiency when they become the water preferred path; thus, retaining water flowing within the batter. The bore’s longevity is considered the period of the bore is considered effective. Water flow measurement is suggested as a reliable measure to assess bores’ longevity.
- Description: Masters by Research
- Authors: Perdigao, Cristhiana
- Date: 2021
- Type: Text , Thesis , Masters
- Full Text:
- Description: Horizontal bores are essential infrastructures for maintaining the stability of open-pit mine batters. The infiltration of water from large surface catchments during rain events and induced deformation caused by mining activities can cause the build-up of pore water pressures in mine batters, potentially leading to catastrophic slope failures. A field investigation unit containing a camera has been developed to survey long (>300m) horizontal bores. Features observed using the camera along the profile of horizontal bores are discussed. Water flow was quantified by flow meters. X-Ray Diffraction (XRD) was undertaken to investigate the water precipitates within the selected bores. Water flow temperature was recorded to test the hypothesis of a possibility to indicate whether a borehole was draining from the saturated zone or from the surface water through its temperature. The investigations have been conducted to determine the cause of change in the efficiency of horizontal boreholes and find a reliable measure to assess longevity and performance of horizontal drains. Bore efficiency has been defined as the bore functioning as a preferential path for water within the batter to be drained out to reduce the saturated zone and associated pore water pressures within the batter. The results suggest blockages and fractures inside the bores can be considered the leading cause of the change in the efficiency of a bore. Blockages occur because of sediment accumulation and because of coal chunks from internal wall collapses. Internal fractures affect efficiency when they become the water preferred path; thus, retaining water flowing within the batter. The bore’s longevity is considered the period of the bore is considered effective. Water flow measurement is suggested as a reliable measure to assess bores’ longevity.
- Description: Masters by Research
Inspection of open-pit mine drainage characteristics with a horizontal borehole camera
- Perdigao, Cristhiana, Dyson, Ashley, Yaghoubi, Mohammadjavad, Baumgartl, Thomas
- Authors: Perdigao, Cristhiana , Dyson, Ashley , Yaghoubi, Mohammadjavad , Baumgartl, Thomas
- Date: 2021
- Type: Text , Conference paper
- Relation: 14th Baltic Sea Region Geotechnical Conference, BSGC 2020 Vol. 727
- Full Text:
- Reviewed:
- Description: Horizontal bores and drains are crucial infrastructures for maintaining the stability of large open-pit mines. Induced deformations as the result of mining activities and the infiltration of water from large surface catchments during heavy rain events can cause the build-up of pore water pressures in brown coal batters. This can potentially lead to catastrophic slope failures. Horizontal boreholes and drains are commonly installed at shallow inclines and typically range in length from 150 to 400 metres. Due to complexities in surveying lengthy horizontal bores, the long-term internal properties of these structures are poorly understood. In this research, a specialised horizontal borehole camera was developed to observe a range of factors influencing borehole performance including the identification of fractured or jointed material, borehole geometry and features, and locationally dependent water outflow and drainage paths. Investigations were undertaken at an operational brown coal mine in the Latrobe Valley, located in Victoria, Australia. Features observed on the profile of horizontal bores are discussed, with an emphasis on providing in-situ material characterisation and for the purposes of maintaining stable mine batters. © Published under licence by IOP Publishing Ltd.
- Authors: Perdigao, Cristhiana , Dyson, Ashley , Yaghoubi, Mohammadjavad , Baumgartl, Thomas
- Date: 2021
- Type: Text , Conference paper
- Relation: 14th Baltic Sea Region Geotechnical Conference, BSGC 2020 Vol. 727
- Full Text:
- Reviewed:
- Description: Horizontal bores and drains are crucial infrastructures for maintaining the stability of large open-pit mines. Induced deformations as the result of mining activities and the infiltration of water from large surface catchments during heavy rain events can cause the build-up of pore water pressures in brown coal batters. This can potentially lead to catastrophic slope failures. Horizontal boreholes and drains are commonly installed at shallow inclines and typically range in length from 150 to 400 metres. Due to complexities in surveying lengthy horizontal bores, the long-term internal properties of these structures are poorly understood. In this research, a specialised horizontal borehole camera was developed to observe a range of factors influencing borehole performance including the identification of fractured or jointed material, borehole geometry and features, and locationally dependent water outflow and drainage paths. Investigations were undertaken at an operational brown coal mine in the Latrobe Valley, located in Victoria, Australia. Features observed on the profile of horizontal bores are discussed, with an emphasis on providing in-situ material characterisation and for the purposes of maintaining stable mine batters. © Published under licence by IOP Publishing Ltd.
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