Primary Mining Method
Sub-Level Longhole retreat.
Information
BLASTING SEQUENCE
At least two rows are blasted at once. The biggest blast takes 10 to 12 rows at once. The average tonnage per blast is 1814 t (2000 short tons), but can be as much as 4536 to 5443 t (5000 to 6000 short tons). The blast size is limited by the availability of delay periods (detonators). A better fragmentation is achieved if the centre hole is blasted before the hanging wall and the footwall holes, as opposed to blasting all rows of a section at once.
Blasting agent: Anfo (ammonium nitrate). Generally, the holes are double prime, halfway and uphole. If the holes are wet, straight dynamite is used.
Primary Mining Method
Cut-and-Fill mining method.
Information
Blasting can only be done at the end of the shift. The blasting agent, Anfo (ammonium nitrate), is used and primed with boosters and non-electric detonators (Nonel). For the breasting sequence, the blasted advance is 1.8 m to 3 m (6 ft to 10 ft) long on both sides of the stope.
The destress blast is different because the entire lift is blasted at once. The longer holes are completely filled with Anfo (ammonium nitrate) and blasted with the shorter holes.
Attached Documents
Primary Mining Method
Sub-Level Longhole stoping.
Information
EXPLOSIVE PRODUCTS FROM DYNO
Blasting agent: Anfo (ammonium nitrate), DYNO.
Double prime with non-electric detonators, Nonel MS short delays.
Explosive: booster sensitive, water resistant, packaged emulsion, BLASTEX in wet conditions.
Biggest blast done: 18 144 tons (20 000 short tons). In general, the blast is ranging between 1814 and 2722 tons (2000 and 3000 short tons). The size is limited by the number of delays (500 ms).
Attached Documents
Secondary Mining Method
Longhole transverse.
Information
EXPLOSIVE PRODUCTS FROM DYNO
Blasting agent: Anfo (ammonium nitrate), DYNO.
Double prime with non-electric detonators, Nonel MS short delays.
Explosive: booster sensitive, water resistant, packaged emulsion, BLASTEX in wet conditions.
Biggest blast done: 18 144 tons (20 000 short tons). In general, the blast is ranging between 1814 and 2722 tons (2000 and 3000 short tons). The size is limited by the number of delays (500 ms).
Attached Documents
Primary Mining Method
Sequential grid down dip.
Information
Blasting is initiated at the end of the shift.
A blasting agent is used, ANFO (ammonium nitrate).
Primary Mining Method
Long-hole bench stoping with backfill.
Information
Anfo (ammonium nitrate) and boosters are used as blasting agent. Generally, a 1-m (3.3 ft) collar is left uncharged. A blast usually consists in five to twelve holes with one to two holes per ring.
Primary Mining Method
Overhand cut-and-fill.
Information
Blasting is authorized during the shift. The miners have to evacuate the sector and then blast.
Secondary Mining Method
Underhand cut-and-fill.
Information
Blasting is authorized during the shift. The miners have to evacuate the sector and then blast.
Primary Mining Method
Mechanized Cut-and-Fill.
Information
A free space of 30 cm to 60 cm (1 ft to 2 ft) is left after backfilling the stope for the blasting of the breast.
Perimeter blasting is used and has given good results. In the perimeter blasting, they have used low density Anfo (ammonium nitrate) and Xactex (nitroglycerin-based explosive). They are now using Detagel, a continuous perimeter powder. For perimeter blasting, this product is preferred since it is easy to use.
Secondary Mining Method
Longhole open stoping.
Information
EXPLOSIVES PRODUCTS FROM DYNO
- Mostly Anfo (ammonium nitrate).
- If the ground is fractured, packaged watergel explosives are used and loaded with a bazooka loader.
In the blasting sequence, the raise is shot first. Then, 2 to 3 rows are blasted and mucked out completely. The next blast can be bigger because of the free space available.
Primary Mining Method
Sub-level long-hole retreat with backfill.
Information
The main blasting agent used is ANFO (ammonium nitrate). The ANFO is loaded with a pneumatic equipment. The density of the explosives in place is 0.95 kg/m². Each hole is initiated with one cartridge and one non-electric detonator (Nonel). Generally, two rows are blasted at once and the ore is mucked out immediately.
Some tests were performed with emulsion explosive in wet holes.
EQUIPEMENT: Getman carrier.
Primary Mining Method
Longwall.
Information
Refer to attached plan.
Attached Documents
Primary Mining Method
Open stope.
Information
Blasting agent: ANFO (ammonium nitrate).
The holes are ignited in pairs.
Generally, 5 to 6 rows are blasted at once.
Attached Documents
Primary Mining Method
Retreating Longhole.
Information
In narrow areas, a 76-mm (3 in) hole diameter is preserved and the holes are charged with low density explosives.
The blasting length is limited from 2 m to 3 m (6.5 ft to 9.8 ft).
Usually, for stope heights of 17 m to 20 m (55 ft to 65 ft), the blasting gives successful results. For stope heights of 20 m to 25 m (65 ft to 82 ft), sometimes rock pillars remain in stope (bridges).
Primary Mining Method
Long-hole.
Information
Standard Anfo (ammonium nitrate) with two detonators per hole, one at the centre and one at the bottom of the hole.
Secondary Mining Method
Room-and-Pillar.
Information
The blasting progresses with an advance in the drift. The stope is then widened to the average extent of 6 m (20 ft).
Primary Mining Method
Long hole open stope.
Information
The holes are loaded with Anfo (ammonium nitrate). Only the holes with a length over 15 m (49 ft) are ignited in double.
Generally, 3 to 4 rows are blasted at once, approximately 1500 t per blast. The powder factor is 0.65 to 0.70 kg/t.
Primary Mining Method
Long-hole sublevel retreat.
Information
- Before planning a blast, the main geological structures are located.
- Each blast is planned in a way that the brow is not located near major structures in order to minimize instability risks.
- When the holes are dry, a blasting agent, ammonium nitrate (Anfo) is used.
- Plastic liners are used for wet holes and/or when ground void and broken ground have been identified.
- If the ground is wet, water resistant emulsion is used.
- The holes longer than 10 m (33 ft) are double ignited.
- A collar of 0.5 m (1.6 ft) minimum is left for each hole.
- To minimize the damages in the brow, 2-m long (6.6 ft) collars are not loaded.
- The holes along the hanging wall and the last row are loaded with a low density explosive (Impact 50/50).
EQUIPMENT
Utility vehicle GETMAN with telescopic ladder.
Attached Documents
Primary Mining Method
Longhole modified Avoca.
Information
The blasting parameters are the following:
POWDER FACTOR
- 0.2 to 0.5 kg/t for widths higher than 3 m (10 ft).
- 0.5 to 1.0 kg/t for widths of 2 m to 3 m (6.6 ft to 10 ft).
- 1.0 to 2.0 kg/t for widths lower than 2 m (6.6 ft).
Number of rows per blast: 1 to 5.
Minimum distance between charges: equal to or greater than the burden.
Minimum collar length: 20 times diameter of hole.
Delays between holes of a same section: 20 to 50 milliseconds.
Delays between sections: 10 to 30 milliseconds per metre of burden.
Primary Mining Method
Modified Avoca.
Information
The loading of boreholes is done from the upper drift (down the hole), eliminating the need for miners to work near open brows. Therefore, the ore drift is required to remain serviceable for in excess of one year and will be used initially as down hole drilling drives and then as loading levels. Personnel will be restricted entry into the loading levels by the use of tele-remote loaders. Furthermore, the loading does not require pneumatic methods which results in a lower placement density of the explosive.
It is planned to use low density ANFO (ammonium nitrate), 50% strength explosive, for the hanging wall hole as well as the centre hole. The footwall hole will be charged with standard ANFO (ammonium nitrate). The holes will be charged, leaving an unloaded section of 1 m (3.3 ft) at the bottom and at the top of the stope. The total charged length will then be 11 m (36 ft). The powder factor will be approximately 0.4 kg/t (14 oz/t) for an average stope width of 2.1 m (7 ft).
Primary Mining Method
Mechanized cut-and-fill stoping.
Information
All holes charged with prill explosives will have a 0.3-m (12 in) uncharged collar. Therefore, the total charged length of the holes is 2.5 m (8.2 ft). Experience has shown that in these applications, a good fragmentation is achieved without difficulty. All hanging wall and back holes are charged with decoupled explosives (Trimmex or Yellow-tube) to minimize perimeter blast damage.