Jack Caldwell, PE

Mine And Waste Disposal Facilities Experience

Mr. Caldwell has worked on mines and waste management projects in southern Africa, Europe, Canada, and the United States. He has designed, overseen construction of, and reclaimed facilities on projects involving mine tailings impoundments, mine rock dumps, heap leach pads, landfills, and radioactive waste disposal units. He has focused on the civil and geotechnical aspects of site characteristics, site preparations, liner design and construction, material preparation and placement, cover design and construction, and surface water management facilities. Selected mine projects he has worked on include:

  • Meridian Beartrack Mine, Idaho. Jack Caldwell is currently (2005) preparing reclamation plans for a 140-acre heap leach pad. He is preparing reports, construction drawings, and cost estimates to support permitting and construction of a low permeability cover, surface water management facilities, and wetlands at the site. A low permeability cover is required to reduce seepage from the pile, hence to reduce the need to treat seepage water to the very low standards required by the site's NPDES permit. Jack Caldwell is leading a detailed evaluation of the hydraulic performance of the heap leach pad, including characterization of liner effectiveness, drain performance, internal flow paths, transient drainage times, unsaturated sideslope soil cover infiltration, top deck geomembrane cover performance, and surface water management to minimize percolation inflow.
  • Royal Mountain King Mine, California. Jack Caldwell prepared the technical background evaluations and made technical presentations to the Central Valley Regional Water Quality Control Board in connection with mine waste disposal facilities' closure at the Royal Mountain King Mine. He worked with Meridian technical staff to characterize the hydraulic performance of the tailings impoundments, rock dumps, heap leach pads, and water reservoirs on the property. The focus was on site groundwater flow paths, facility liner performance, material permeability and flow characteristics, and cover performance.
  • Cannon Mine Tailings Impoundment, Wenatchee, Washington. Jack Caldwell was the design and construction oversight engineer on the Cannon Mine Tailings Impoundment in Wenatchee, Washington. This is a 300-foot-high earth and rockfill embankment that impounds the tailings from a gold mine - the impoundment is now full, the reclamation cover is in place, and the top of the impoundment is used for apple orchards.
  • Greens Creek Impoundment, Alaska. Jack Caldwell was Design Engineer and Project Manager for the design of the Greens Creek tailings impoundment. This involved site investigations for and design of an earth embankment and associated works for an earth dam on very soft clays and soils.
  • Miscellaneous Mine Projects in Southern Africa. Mr. Caldwell was responsible for the design and construction supervision of numerous tailings impoundments for gold, platinum, diamond, phosphogypsum, and other mines. He managed civil, geotechnical, and groundwater engineers on project implementation including site characterization, design, report preparation, and construction supervision. For numerous mines in South Africa, Botswana, Namibia, and Zimbabwe, he designed, constructed, and consulted on the operation of tailings impoundments, rock dumps, and other waste disposal facilities.