Crandall Canyon Shaft Project

PLATEAU

MINING

CORPORATION

Crandall Shaft Depths

Crandall Canyon Shafts 1470 & 1456 feet Deep

Crandall Canyon Shaft Vs L.D.S. Church Office Bldg.

About 3 ¼ LDS Church Office Buildings

Crandall Shaft Volumes Both Shaft approx. 46,000 yds 158 - 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

Collar - 6822'

Fan Drifts (2)

5775'

Collar - 6780'

20' Diameter Exhaust Shaft~1457' Deep

Water Level 12/2002 5785'

5861'D Seam #5 Mine

5324'5402'5352'

5623'5542'

A Seam

Sub 3 Seam #3 Mine

26' Diameter Intake Shaft~1470' Deep

1044'

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 Gradenear exhaust shaft

Stream Grade CompleteTop Soil Placement

Intake Shaft, Final Reclamation

Crandall Canyon Shaft ProjectPermanent Reclamation

PLATEAU

MINING

CORPORATION