Mount Morgan Mine Site

Queensland, Australia

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Project Description

Mount Morgan is a historic mine site located next to the township of Mount Morgan, near Rockhampton, Queensland. Between 1882 and 1981, gold and copper were mined using underground and open cut techniques. The mine closed in 1990 after retreatment of tailings, which were placed into the open cut. In 1993, the State of Queensland accepted environmental liability for the site with technical oversight by the Department of Mines and Energy (now NRME). The site is characterized by problems associated with acid rock drainage, which has impacted the site and a nearby river (Dee River). The NRME undertook a series of studies to identify key contaminant sources, understand water movement on site and develop a range of rehabilitation scenarios for the site. See also the NRME website for more details.

Robertson GeoConsultants Inc, in association with O'Kane Consultants Inc and Fawcett Mine Rehabilitation Services, was retained by NRM&E to perform a groundwater assessment of the site to characterize the local groundwater system. Robertson GeoConsultants Inc. designed and supervised a detailed field investigation, which was comprised of drilling, monitoring bore installation, hydraulic testing and water quality sampling.

Robertson GeoConsultants Inc. used the results of the field investigation to construct a 3-D groundwater model for the site. The model was used to develop an understanding of the current groundwater conditions on site, and to estimate the contribution of seepage from each of the various mine waste units to the ground water system. The model was also used to evaluate the effectiveness of the seepage interception system (SIS) currently in place and estimate the amount of contaminated water bypassing the SIS and entering the Dee River. Furthermore, the model was used to determine the influence of various closure scenarios for the open cut on the groundwater system. In conjuction with the groundwater model, a 3D digital terrain model was developed for the site to estimate the volume of the various mine waste units.

As a subcontractor to Connell Wagner, Robertson GeoConsultants Inc was also retained to evaluate the various remedial options for historic dams in Dee River. The study included an impact assessment of various rehabilitation options on the local groundwater flow regime, the seepage interception system and on contaminant loading in the river.

Since the orginal field investigation and modeling work, Robertson GeoConsultants has performed annual groundwater monitoring reviews of the site and continues to assist in routine monitoring.

Services Provided

  • Groundwater review and assessment;
  • Design and supervision of groundwater field program (drilling, installation, hydraulic testing)
  • Development & calibration of a 3D ground water flow model (MODFLOW);
  • Development of a 3D digital terrain model;
  • Impact assessment and closure strategies;
  • Assistance in routine monitoring (Reporting, QA/QC).

Papers

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