This project involved a proposed in-situ retort oil shale mine located in Piceance Creek Basin, Rio Blanco County, Colorado. The scope of work included: (1) prepare a mine layout and operations plan, (2) evaluate the existing facilities and develop plans and estimates for modifications to support the new mining plan, (3) develop design engineering, cost estimate and schedule of new 1800-ft-deep off-gas (high temperature gas) shaft, (4) review condition of existing shafts, shaft liners, and hoisting equipment and facili-ties, (5) design new mine and MIS support facilities, and (6) prepare a capital and operating cost estimate for mining and retort development.
The mine layout was developed to utilize the existing shafts and shaft stations, minimize development costs while main-taining essential safety functions. Seventeen retorts and room-and-pillar areas were considered for supplementary oil shale production. The modified in-situ process required a dedicated off-gas exhaust shaft involving selection of construction methods, design, and a cost estimate.
Of the existing facilities, shaft liners needed some upgrade, stations required remedial attention, water handling in the shafts required installation of new control measures, and hoisting systems needed some refurbishment. Loading pocket facilities required completion, provision made for shaft bottom clean-out, and the headframe loadout modified.
The design of the new mine and MIS support facilities incorporated mining sequencing, ground support, mining equipment selection, materials handling, ventilation, and underground services. The capital cost estimate, prepared from design drawings, included a detailed scope of work and engineering estimate for Year 1 of the project. An operating cost estimate for the mine was also prepared following similar procedures. A spreadsheet-based cost model was used to facilitate mining cost calculations.