Trusses & Slings
Cable Length and Spacing
|Distance Between Holes||Drill Hole Length||Total Length of Cable|
|11.5' (3.5 m)||8' (2.4 m)||27.5' (8.3 m)|
|13.1' (4.0 m)||8' (2.4 m)||29.1' (8.8 m)|
|14.8' (4.5 m)||8' (2.4 m)||30.8' (9.3 m)|
|16.4' (5.0 m)||8' (2.4 m)||32.4' (9.8 m)|
|18' (5.5 m)||8' (2.4 m)||34' (10.3 m)|
|19.7' (6.0 m)||8' (2.4 m)||35.7' (10.8 m)|
In Mexico cable slings are supplied complety assembled and ready to install.
Cable slings can be used as primary ground support in drifts, for the construction of sill mats and for wrapping pillars. Cable slings are particularly useful in soft, yielding ground or in areas prone to rockbursts.
Each sling is comprised of a length of cable (see chart below) with drive blocks or buttons, 2 pc. of 5' (1.5m) 39mm friction stabilizers and a minimum of 6 cement cartridges (32mm diameter), three per hole. Cables can be either 0.5" (12.7 mm) or 0.6" (15.2 mm).
Holes are always drilled 8' (2.4m) in length and are generally oriented at approximately 45 degrees. Three cement cartridges are immersed in water, and when ready, inserted into the first hole and tamped to the end. One end of the cable is then inserted manually into the hole. The cable is slid into the gap in the end of the friction stabilizer and the bolt is fully installed. The same process is repeated for the other end of the cable.
If properly installed the friction stabilizers will hold approximately 1 ton per foot of length and will immediately tension the cable. Blocks or wedges can be inserted between the cable strand and the rock. After the cement cures the full strength of the cable can be mobilized.