Primary Mining Method

Information

ALL ZONES

• Length: No limit.
• The longest stope: 46 m (150 ft).
• Height: 20 m (65 ft) sill to sill. For a final height of open stope of 91 m (300 ft).
• Width: average thickness of 6 m (20 ft). The smallest stopes are 3 m to 4.6 m thick (10 ft to 15 ft). Dip is nearly vertical.
• RMR: approximately 75, average 80.
• Backfill type: Waste rock generated from development is dumped in the mined out open stopes. The backfill is not part of the mining sequence, but a way to manage the waste rock.

Primary Mining Method

Information

• Length: 122 m (400 ft).
• Height: 91 m (300 ft).
• Width: 1.8 to 2.4 m (6 ft to 8 ft).
• Dip: 65 to 75 degrees.
• Distance between levels: 91 m (300 ft).
• Backfill type: mill tailing.

Primary Mining Method

Information

SUB-LEVEL LONG-HOLE STOPING METHOD

• Length: 21 m to 37 m (70 ft to 120 ft).
• Total height: 24 m (80 ft).
• Stope height: 15 m (50 ft).
• Height of upper and lower drifts: 4.6 m (15 ft).
• Width: 2.4 m (8 ft) at 70 degrees.
• Distance between levels: 15 m (50 ft) back to floor.
• Dip: 65 degrees.

Sub-level long-hole stoping method with multiple longitudinal panels utilizing delayed backfill is approximately 90% of the production.

RMR
Rock Quality Designation (RQD) -  walls: 80%.
Rock Quality Designation (RQD) - mineralized zone: Quartz.
Backfill used: Rockfill with cemented pillar.

Secondary Mining Method

Information

LONG-HOLE TRANSVERSE METHOD

• Length: 24 m (80 ft)
• Total height: 24 m (80 ft)
• Stope height: 15 m (50 ft)
• Height of upper and lower drifts: 4.6 m (15 ft)
• Approximately 10% of the production.

Primary Mining Method

Information

Only one zone.

• Length: 300 m to 320 m (984 ft to 1050 ft)
• Width: 75 m (246 ft) of open stopes with pillars of 38 m (125 ft) between stopes
• Minimum excavation height: 1.3 m (4.3 ft). This minimum height is required to ensure enough working space after wall movements produced by high pressures. The thickness of the vein varies from a simple contact up to 3 m (9.8 ft) and more.
• Distance between levels or sub-levels: 145 m (475 ft) vertically, which is equal to 300 m to 320 m (984 ft to 1050 ft) on axis of the lode.

Primary Mining Method

Information

• Length: 12 m to 15 m (39 ft to 49 ft) if backfilled.
• Height: 10 m to 15 m (33 ft to 49 ft).
• Ore width: 0.1 m to 1.5 m (4 in to 5 ft).
• Backfill type: Waste rock.

Traditionally, Kundana has used the long-hole open stope benching. More recently, they have turned to a long-hole bench stoping with backfill.

Primary Mining Method

Information

GOLD HUNTER

• Length: approximately 23 m (75 ft)
• Minimum width: 2.1 m (7 ft)
• Mining method used: Underhand and Overhand cut-and-fill
• Backfill used: Paste fill

Secondary Mining Method

Information

LUCKY FRIDAY

• Minimum width: 1.8 m (6 ft)
• Mining method used: Underhand cut-and-fill
• Backfill used: Paste fill

GOLD HUNTER

• Length: approximately 23 m (75 ft)
• Minimum width: 2.1 m (7 ft)
• Mining method used: Underhand and Overhand cut-and-fill
• Backfill used: Paste fill

Primary Mining Method

Information

• Length, height and width: depends on the ore geometry.
• Dip: 60 to 75 degrees.
• Backfill used: Hydraulic fill or rock fill.

Secondary Mining Method

Information

• Length: generally 30-m (100 ft) panel but can vary depending on the area.
• Maximum height: 18 m (60 ft).
• Minimum height: 6 m (20 ft).
• Distance between levels: 18 m (60 ft).
• Dip: 60 to 75 degrees. If the dip is less than 55 degrees, this method is not used.
• Backfill used: Hydraulic fill.

Primary Mining Method

Information

WALTERS ZONE

• Stope height: 15.5 m (50.8 ft).
• Minimun width: 1.3 m (4 ft) up to 7 m (23 ft).
• Average of 2 m to 2.5 m (7 ft to 8 ft).
• Dip: 45 degrees to 50 degrees.
• Floor to floor spacing of 20 m (66 ft).
• RMR (mineralized zone): 38 to 40. Cemented aggregate fill or rough waste is used as backfill.

Primary Mining Method

Information

• Width: 120 m (393 ft) between opening raises.
• Length: 300 m (984 ft) along strike.
• Thickness: 85 cm (33.5 in).
• Dip: approximately 90 degrees.
• Distance between levels or sub-levels: 50 m (164 ft) vertical.

Primary Mining Method

Information

LOTUS DEEP ZONE

• Total length of the zone: approximately 1000 m (3280 ft).
• Height: 17 m (56 ft).
• Blasted width: 1 m (3.3 ft).
• Average width obtained: 1.5 m (5 ft).
• Dip: 70%.
• Distance between level or sublevel: 17 m (56 ft) floor to floor. The good ground conditions allow open stoping to be employed with random low grade waste pillars.
• RMR (walls and mineralized zone): Excellent.

Primary Mining Method

Information

• Width: 30 m to 35 m (98 ft to 115 ft).
• Height: 20 m (66 ft) with a dip over 40 degrees.

Average of 10 m (32.8 ft) with a dip under 40 degrees (15 m to 20 m [49 ft to 65 ft] depending on the dip). The span is 20 m (66 ft) for the upper levels. The span is 10 m (32.8 ft) for the lower levels since the dip is less than 40 degrees. Very good quality rock mass: Q = 7 to 20

Two mining methods used:

1. Retreating longhole.
2. Modified Avoca (no description on this web site). Backfill type used: Unconsolidated rock fill.

Primary Mining Method

Information

GOLDEN AGE REEF

• Length: 20 to 25 m (66 to 82 ft) and a pillar of 3 to5 m (10 to 16 ft) is left.
• Height: 17 m (56 ft) vertical, (20 to 25 m [66 to 82 ft]).
• Width: Average thickness of 1.6 m (5 ft). The vein varies from a few centimetres to 4 m (13 ft).
• Dip: 39 degrees (35 to 40 degrees).
• Distance between levels: 17 m (56 ft) vertical.

Secondary Mining Method

Information

• Length: 20 to 25 m (66 to 82 ft) and a pillar of 3 to5 m (10 to 16 ft) is left.
• Height: 17 m (56 ft) vertical, (20 to 25 m [66 to 82 ft]).
• Width: Average thickness of 1.6 m (5 ft). The vein varies from a few centimetres to 4 m (13 ft).
• Dip: 39 degrees (35 to 40 degrees).
• Distance between levels: 17 m (56 ft) vertical.

Primary Mining Method

Information

• Length: variable.
• Height: variable.
• Width: average of 5 m (16.4 ft).
• Dip: 70 degrees.
• Maximum distance between levels: 15 m (49 ft) but can reach 6 m (20 ft).
• RMR (rock mass rating) for walls and mineralized zone: very good rock quality.
• No backfilling.
• Mining method used: Retreating longhole open stoping method.

Primary Mining Method

Information

Yilgarn Star Deep (future zone)

• Length: 25 m (82 ft) and a pillar of 3 m (10 ft) is left.
• Height: 20 m (66 ft) floor to floor.
• Thickness: 2.5 m (8.2 ft) minimum.
• Dip: 55 to 75 degrees.
• Distance between levels or sublevels: 20 m (66 ft) floor to floor.
• Backfill type: Non-consolidated waste rock.

Primary Mining Method

Information

ZONE 1A

• Length: 18 m (59 ft) for planning reasons but can reach up to 25 m (82 ft).
• Height: 18.5 m (61 ft) without the sub-levels.
• Minimum width: 2 m (6.6 ft). Generally from 4 m to 5 m (13 ft to 16 ft).
• Dip: 75 to 90 degrees.
• Distance between level or sub-level: 22 m (72 ft) floor to floor.
• Backfill used: Non consolidated rock fill.

HANGING WALL - Metavolcanic = 150-250 MPa.
FOOTWALL - Metasediments = 150-250 MPa.
MINERALIZED ZONE Q = 20-25 Massive ore = 60 - 150 MPa.

Primary Mining Method

Information

• Length: 25 m (82 ft) per block.
• Height: 13 m (43 ft).
• Total stope opening is 21 m (69 ft).
• Width: Averaging 2.1 m (7 ft).
• Dip: 80 degrees.
• Distance between levels: 17 m (56 ft) for future development. Some developments were already completed at 20 m (65 ft) spacing.
• RMR Footwall: predominantly basalt. Fair quality rock mass.
• Hanging wall: predominantly ultramafic. Poor to very poor quality rock mass.
• Mineralized zone: Poor quality.
• Backfill used: Unconsolidated material.

MINING METHOD
The modified Avoca mining method has been selected to meet the following factors:

• narrow vein
• steeply dipping
• poor quality of the hanging wall
• good productivity
• low mining cost
• extraction from bottom up, this eliminates the need for leaving crown pillars
• tele-remote loading, reducing the exposure of miners

 In 1995, a feasibility study recommended a mechanized cut-and-fill method, with some conventional airleg cut-and-fill on the very narrow lodes. Where ground conditions permitted, an Avoca style up-hole benching method or Alimak long-hole method was recommended. The Avoca method allows for ground control using a combination of cable bolts and backfill, whilst allowing the extraction of high tonnages in comparison to jumbo cut-and-fill systems. The planned sequencing allows for a consistent extraction rate at a low unit cost in comparison to other narrow vein mining methods.

Attached Documents

• Long section with Modified Avoca (Picture)

Primary Mining Method

Information

WANNAWAY NO2 LODE

• Length: Variable length between 51 m to 250 m (167 ft to 820 ft).
• Height: 3.3 m (11 ft). This is based on 5 lifts per stoping block to a total 21 m (69 ft) vertically. Including a 1-m (3.3 ft) brow, the face will be 4.3 m (14 ft) high which is an optimum size for the single boom jumbo.
• Width: 3.3 m (11 ft) minimum and increases depending on the vein width.
• Dip: averaging 65 degrees. The stope are designed to allow for profiling the hanging wall to a minimum hanging wall angle of 65 degrees.
• Distance between level or sub-level: The level interval between each stoping block is 21 m (69 ft), representing 5 lifts. This was derived from calculating the most efficient use of a single access assuming a maximum ramp design of 1:7 more or less and based on the known total vertical extend of the NO2 lode.
• RMR Hanging wall (ultramafic): Poor to very poor quality rock mass.
• Footwall (basalt): Good quality rock mass.
• Mineralized zone: Fair quality rock mass.