GIA Industri AB

Malmberget

Methods

When working the Malmberget method the pre-drilled hole is first filled with grout after which the cable is inserted, cut and fixed in position. The cable used can be of type 2 or type 3 (see Cable types).

Grouting first, cable inserting afterwards

The drill hole is grouted through a plastic hose feeded into the bottom of the hole and then...

... slowly pulled out (like charging explosives).

Afterwards 1–3 cables are pressed into the grout. This method is most suitable for holes with an inclination of up to +30 degrees from the vertical plane. The cable is fixed in the hole, by bending it against the roof and then insert it the last meter.

Cassette Solution – Malmberget Method


Remote Control	Pump and mixer	Cable Cassette


Hose Reel	Crane	Cable and Hose Feeder

Frame


Cassette model for Lorry	Cassette model for Loader

Platform on Scissors Lift

Kiruna Method

Cable insertion first, grouting afterwards

When working the Kiruna method the steel cable used is of the center hose type (see Cable types). When the cable has been inserted it is fixed by a special clamp, grout is pumped in and air/water escapes through the centerhose..

The cable is inserted into the hole and fixed by a special clamp.

By help of an injection nozzle, the grout is pumped from the opening to the bottom of the hole.

The cable is also completed with an air bleeding hose, built in the center of the cable or attached outside.


	The special cable is normally delivered on a drum from the manufacturer. The cable can be fixed in the drill hole, either by bending two threads at the upper end of the cable or by fixing clamps by help of the clamp unit mounted at the end of the boom.

Cassette Solution – Kiruna Method


Remote Control	Injection Nozzle	Pump and mixer


Cable Cassette	Crane	Cable and Hose Feeder

Frame


Cassette model for Lorry	Cassette model for Loader

Platform on Scissors Lift

Capacity

With our concept the drilling and cable-bolting is done with separate equipment. Normal production drilling and drilling for cable bolting can be done in a parallel cycle, thus leading to a more efficient use of the drill-rig and reduction of costs.

DRILLING – production and cable bolting drilling

Capacity: up to 300 m/shift.

Cable Bolting – multi-use of loader

Capacity: 250–500 m/shift.
Increased flexibility by multi-use of the loader or by use of a second hand loader. Can be combined with shot creting (spraying nozzle on the crane and a pump or a rotary unit on the frame). Reduced costs.

The GIA cable-bolter can insert three types of steel cable. Depending on your application you can choose between center hose cable (type1), regular steel cable (type2), or birdcage cable (type3). The GIA cable-bolter is the only machine on the market that can use all three types without extensive modifications.

Cable Tests

Cement grouted cabelbolt -plain twin steel strand

Test 1.
Cable diameter: 2 x 15.2 mm.
Ultimate tensile strength of cable: Approx 500 kN (50 tons).
Type of face plate: Flat plate.
Cable length: 3 metre.
Borehole diameter: 64 mm. Recomended diameter, minimum 48 mm.
Cement grout: W/C ratio 0.35, curing time 11 days. After insertion of the cable bolt into the borehole, the cement grout was injected through a grout inlet tube at the bottom of the borehole. The grout injection was discontinued as the borehole was full of grout.

Division of Structural Engineering, University of Technology. Extracts from paper given by prof. Bengt Stillborg.

Test 2.
Double Birdcageed Cable & Bridon Rope
450 mm DOUBLE EMBEDMENT
32 mm 6x7 (6/1) Coreless

Grout Type: Standard
Cure Time: 7 days
Hole Size: 38 mm

	1.32 mm 6x7 (6/1) Max. Load 666 kN Cable Failure
	2.32 mm 6x7 (6/1) Max. Load 655 kN Cable Failure
	Double Birdcaged Cable Max. Load 602 kN Cable Failure
British Coal Corporation, Rock Mechanics

Test 3.
Flexirope -special ropes for rockbolting.

SwedWire in cooperation with the Swedish mining company LKAB and researchers in the sphere of rockbolting and rock mechanics have constructed two special ropes, FLEXIROPE 26 and FLEXIROPE 34 for rockbolting purposes. FLEXIROPE are the first steel wire ropes developed for special use for rockbolting in tunnels and mines and today they reinforce the rocks in many swedish mines.

FLEXIROPE is installed with cement grout as cast mass in hole size from 35 mm and up. The hole length can be short or long, from 2 metres up to 60 metres or even longer depending on the rope being used as conventional bolt or for rockbolting. FLEXIROPE consist of 8 strands alternately laid round a polyethylene hose, which works as airing hole. Regarding the bolt length total flexibility can be obtained due to the fact that FLEXIROPE is delivered on wooden drums and is not cut until it has reached the bottom of the hole at installation. Drumsize and rope length can be delivered according to the requirement of the customer.

	PC strand 185,130 2x15.2 mm
	Flexirope 26 mm

	Rope dia.	Min. breaking load	Weight	Hose size
Flexirope 26	26 mm	330 kN	1.9 kg/m	2x2 mm
Flexirope 34	34 mm	560 kN	3.3 kg/m	16x2 mm

Economy

Cost Comparison (Excl. Cap. Cost) in SEK (1 SEK = 0.125 USD)
Bolts are mounted with a drilling/bolting unit (Atlas Copco Boltec). Cables are mounted/grouted whit a cable insertion unit (GIA industri ab) and the drilling with a production drilling unit (Atlas Copco Simba).

	Rebar	Friction anchored bolt	Tubular bolt	Expansion shell anchored bolt	Cable	Resin bolt	Complete resin bolt
Rebar with washer/m	17	-	-	-	-	20	20
Friction anchored bolt w. washer/m	-	48	-	-	-	-	-
Tubular bolt with washer/m"	-	-	81	-	-	-	-
Expansion shell anchored bolt with washer/m	-	-	-	28	-	-	-
Cable/m	-	-	-	-	7	-	-
Labour costs drilling/m	10	10	10	10	10	10	10
Labour costs mounting/m	12	4	12	4	4	5	6
Grout/m	1.1	-	1.1	-	1.1	-	-
Resin costs	-	-	-	-	-	20.8	52
Maintenance costs drilling unit/m	14	14	14	14	14	14	14
Maintenance costs mounting unit/m	5	-	5	5	3	-	-
Drill steel costs	6.5	6.5	6.5	6.5	7.8	6.5	6.5
Total for 2.3 m bolt/cable	150.9	189.8	298.1	155.3	107.9	175.5	249.6

Cabel = Most economic

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