Crandall Canyon Shaft Project PLATEAU MINING CORPORATION

Crandall Shaft Depths About 3 ¼ LDS Church Office Buildings

Crandall Shaft Volumes  Both Shaft approx. 46,000 yds  Cat 797 haul Trucks (290 yd Capacity)

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.”

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

Innovative use of existing Technology for Western Coal ISSUE:  Very little experience with filling large, deep shafts

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

Size of Shaft  Large Track Hoes Used  Multiple Machines Required  Spotters

Depth of Shaft  Material Handling Move Material with scrapers Use Hoes, and dozers for filling  Ventilation Dump material versus convey Provides ventilation

Methane Issue  1.8% in Exhaust Shaft  Up to 7.5% in Intake Shaft  Mechanical Ventilation of Shaft  Would Ventilation circuit remain in-tact

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

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

Structural Issues Summary  The bottom 50’ of shaft stabilized w/ broken concrete  Broken Concrete through mined Seams  Clay plug to seal water and methane

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

Intake Headframe from Exhaust Shaft Prior to Reclamation

Intake Shaft Headframe & Hoist

Removing Exhaust Cap

Moving Fill Material

Filling Exhaust Shaft

Exhaust Shaft filled/Collar Exposed

Intake Shaft Filled & Collar Demo

Rough Grade at Intake Shaft

Checking Streambed Grade near exhaust shaft

Stream Grade Complete Top Soil Placement

Intake Shaft, Final Reclamation

Crandall Canyon Shaft Project Permanent Reclamation PLATEAU MINING CORPORATION