Bolts
Tru-bolts with a shaft diameter of 10mm and a length of 90mm are the minimum standard. For chain and for lesser quality rock, 12mmx100mm is the recommended standard. Stainless steel is preferred; galvanized coating is acceptable for dry sites.
Chain
Chain with a gauge of 8mm is the minimum standard. Stainless steel is preferred; galvanized coating is acceptable. A galvanized bolt with galvanized chain is the recommended metal combination. It is desirable to not mix metal types in order to reduce potential corrosion.
D Shackle and Oval Malion
A gauge of 10mm is the minimum standard. A gauge of 12mm is the recommended standard. Stainless steel is preferred; galvanized coating is acceptable. It is desirable to not mix metal types in order to reduce potential corrosion.
Bolt Hanger
A fabricated hanger constructed with stainless steel and strength rated is the minimum standard.
Bolt Hanger w/Ring
A fabricated hanger with a ring constructed with stainless steel and strength rated is the minimum standard.
Fabricated Anchor Systems
Fabricated anchor systems constructed with stainless steel and strength rated is the minimum standard.
Anchor Design Recommended Configurations
Bolts
Bolts should be placed perpendicular to the rock with a minimum distance of 200mm from each other, rock edges and cracks. Bolts should be placed in solid rock. Avoid large loose blocks and flakes that are semi-detached.
Two Chains
A length of approximately 250mm or eight (8) links on each chain is the minimum recommended. Longer chain is recommended to avoid obstructions or if the bolts are spaced more than 200mm apart. The chain link that fits over the bolt stud should not be levered against the nut or the rock; the rest of the chain links should have free movement.
One Chain and One Hanger w/Ring
A length of approximately 250mm or eight (8) links on the chain is the minimum recommended. The chain link that fits over the bolt stud should not be levered against the nut or the rock; the rest of the chain links should have free movement. The hanger with ring is placed below the chain vertically so that the ring and the bottom chain link are equalised.
(2x) Two - Bolt Hanger w/Ring
Ideally, the hangers are placed on a horizontal plane in relation to each other with no rock obstruction between them. Each ring should have free movement and be positioned so that they stay perpendicular to the rock when loaded.
Fabricated Anchor System
Fabricated anchor systems should be installed to manufacturer specifications.
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