Henderson Mine Site

Henderson Mine

Central Campus

Shaft CollarElev 10,400 ft

Shaft BottomElev 7,500 ft

LA Ramp

Primary Access Ramp3600 ft

Central CampusElev. 6,750 ft(4200 mwe)

Secondary Access Ramp3200 ft

Fresh air Exhaust air

To crusher

Harrison Mt.Elev. 12,300 ft

UNO

Central CampusElev. 6750 ft(4200 mwe)

Midway CampusElev. 5825 ft(5100 mwe)

Lower CampusElev. 4900 ft(6000 mwe)

EarthLab/GeoscienceArea

Deep Access

Internal Shaft

Preliminary Cost Estimates(Excluding UNO)

Preliminary Time Schedule(Excluding UNO)

UNO Preliminary Cost Estimates

Equipment and Excavation Techniques

2.3.1 Conventional Development

Basic drilling cycle for drill and blast drifting and tunneling:

•Surveying and setup•Drilling•Charging•Blasting•Ventilation•Scaling•Mucking•Scaling•Bolting

3 Boom Drill Jumbo

LHD

Development Haul Truck

Raise Drill Operating Cycle

Sandvik TamrockRock World, 2/2001

Drilling the ventilation raises at the Kiruna Mine, 1998

Shaft Widening by Drill and Blast

Shaft Boring Machine (Wirth)

V-mole method

Raise bored pilot hole 1.8 to 2.4 m diameter.

Ream shaft to up to 8.5 m diameter.

Limited by maximum length raise bored hole, currently 1,300 m.

7.5 m day average