Stope geometry

Apollo Gold Corporation - Diamond Hill mine (U.S.A)

Primary Mining Method

Sub-Level Longhole retreat.
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.

Coeur Silver Valley Inc. - Galena Mine (U.S.A)

Primary Mining Method

Cut-and-Fill 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.

Echo Bay Minerals Co.- K-2 Mine (U.S.A)

Primary Mining Method

Sub-Level Longhole stoping.
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

Longhole transverse.
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.

Gold Fields Ltd - Kloof Mine (South Africa)

Primary Mining Method

Sequential grid down dip.
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.

Goldfields Ltd - Kundana Gold Mine (Australia)

Primary Mining Method

Long-hole bench stoping with backfill.
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.


Hecla Mining Company - Lucky Friday mine (U.S.A)

Primary Mining Method

Overhand cut-and-fill.
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

Underhand cut-and-fill.
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

Homestake Mining Co - Homestake Mine (U.S.A)

Primary Mining Method

Mechanized Cut-and-Fill.
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

Longhole open stoping.
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.

Homestake Mining Co. - Darlot Mine (Australia)

Primary Mining Method

Sub-level long-hole retreat with backfill.
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.

Implats - Impala Platinum Limited (South Africa)

Primary Mining Method

Longwall.
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.

Normandy Mining Ltd - Bronzewing mine (Australia)

Primary Mining Method

Open stope.
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.

Normandy Mining Ltd - Jundee mine (Australia)

Primary Mining Method

Retreating Longhole.
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.

Normandy Mining Ltd - Wiluna mine (Australia)

Primary Mining Method

Long-hole.
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

Room-and-Pillar.
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.

Sons of Gwalia Ltd - Golden Pig mine (Australia)

Primary Mining Method

Long hole open stope.
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.

Sons of Gwalia Ltd - Yilgarn Star Mine (Australia)

Primary Mining Method

Long-hole sublevel retreat.
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.

WMC Resources Ltd - Leinster Nickel Operations (Australia)

Primary Mining Method

Longhole modified Avoca.
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.


WMC Resources Ltd - Miitel Mine (Australia)

Primary Mining Method

Modified Avoca.
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

WMC Resources Ltd - Wannaway mine (Australia)

Primary Mining Method

Mechanized cut-and-fill stoping.
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.