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Published byBernadette Griffith Modified over 9 years ago
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Crandall Canyon Shaft Project PLATEAU MINING CORPORATION
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Crandall Shaft Depths About 3 ¼ LDS Church Office Buildings
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Crandall Shaft Volumes Both Shaft approx. 46,000 yds 158 - Cat 797 haul Trucks (290 yd Capacity)
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Liability for Caps Source: USDA, Natural Resource Conservation Service, Mine Shaft and Adit Closing, July 2000 Enclosures, gates, and caps shall be used only where periodic inspection and maintenance is ensured through a maintenance agreement with a responsible government entity, landowner, or organization.” “Shafts shall be closed with plugs only if another practical solution is not available.”
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Permanent Closure of Mines Source: Openings Hazards and Remediation Handbook - Nova Scotia Department of Natural Resources P. 11 & P.22 Long Term Closure- Concrete caps & Bulkheads Effective 30 to 50 years The installation should be monitored, however, as over time, the concrete will deteriorate, steel reinforcing will corrode and/ or the mine openings may cave or subside. Permanent Closure Backfilling Closure through blasting
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Innovative use of existing Technology for Western Coal ISSUE: Very little experience with filling large, deep shafts
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Innovative use of existing Technology for Western Coal Many issues to deal with Size of Shaft Depth of Shaft Methane Water in the shaft Underground issues unknown Pipes Landings Elevator guide rails Seals
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Size of Shaft Large Track Hoes Used Multiple Machines Required Spotters
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Depth of Shaft Material Handling Move Material with scrapers Use Hoes, and dozers for filling Ventilation Dump material versus convey Provides ventilation
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Methane Issue 1.8% in Exhaust Shaft Up to 7.5% in Intake Shaft Mechanical Ventilation of Shaft Would Ventilation circuit remain in-tact
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Methane Resolution Monitor prior to removal of caps <3% remove exhaust (20’) cap Allow to ventilate <3 % remove intake winze next to (26’) cap Dump material to provide mechanical Ventilation Monitor at top of shaft
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Water in Shaft Determine depth of water FOUND Could cause closure of ventilation circuit Could cause more material to be used Provided for safety in lower part of shaft
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Structural Issues Summary The bottom 50’ of shaft stabilized w/ broken concrete Broken Concrete through mined Seams Clay plug to seal water and methane
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Other Issues Could not cut guide rails at top of shaft. Landings/ pipes may provide for bridging. Steel in shaft could cause for ignition of >5% Methane concentrations
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Intake Headframe from Exhaust Shaft Prior to Reclamation
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Intake Shaft Headframe & Hoist
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Removing Exhaust Cap
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Moving Fill Material
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Filling Exhaust Shaft
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Exhaust Shaft filled/Collar Exposed
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Intake Shaft Filled & Collar Demo
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Rough Grade at Intake Shaft
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Checking Streambed Grade near exhaust shaft
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Stream Grade Complete Top Soil Placement
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Intake Shaft, Final Reclamation
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Crandall Canyon Shaft Project Permanent Reclamation PLATEAU MINING CORPORATION
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