Injection bolts AP-KI-ø42 are designed to support mine working areas as an independent or auxiliary roof support system. AP-KI-ø42 tube injection bolt is used to reduce static load on support system in mining area cut in bad mining and geological conditions, such as:
- faulted zones,
- areas of increased pressure (tail and main gate),
and are used to:
- stabilize floor heaves,
- reinforce rock near sealed, fire and emergency stoppings,
- reinforce brick and concrete lining at shaft bottom, pump chambers, engine house, etc. in case of stability loss,
- reinforce the existing support of mine working area cross-cuts in case of their deformation,
- as fore poling when crossing abandoned workings or other working areas,
- form a mantle to prevent water leakage from shaft and small shaft lining.


Technical description

Bolt rod is made of 18G2A or R55 ø30 x 6,3 steel tube and plain AP 600 or 34GS steelbar ø18,3 mm. At the top tube of ø30 x 6,3 has internal M20 thread for coupling with M20 threaded bar and 4 holes of ø6 for adhesive injection. At the bottom there is M30x2 thread. In the mid-section of the tube there is a stop collar to work with the seal. The seal is a rubber tube ø42/ø31,5 mm and 200 mm in length. The seal expands after applying the tube and M30x2 nut. KE-4W/M20 shell with diameter of ø42 mm is the element which fix the bolt in the hole for thetime of injection. The shell consists of 4 serrated leaves and one plug. A flat square washer of8x150x150/ø31 is used with the bolt.

Technical specification



Tube diameter

ø 30x6,3 mm

Bar diameter

ø 18,3 mm

Tube thread size

M20 internal

M30 x 2 outer

Bar thread size


Bolt length

od 1300 do 5000 mm (or other as required)

KE-4W/M20 shell diameter

ø 42 mm

Head length

93 mm

Bolt capacity

above 120 kN

Nominal injection pressure

10 MPa


Installation procedure

Drill a hole ø 44 ± 0,5mm in diameter and length equal to the length of the bolt. Place the expansion shell on one end of the rod and M30x2 nuts on the other. After inserting the bolt in the hole twist the rod for the shell to expand.
Apply at least 250 Nm torque. After expanding the shell, of the rod should protrude from the hole for 85-95mm surface. After the shell has expanded, M30 x 2 nuts should be undone from the rod. Next, place the following elements on the rod in the right order: seal, tube, square washer, and then fix the M30x2 nut. Use a torque wrench to apply the initial tension of at least 30kN to cause the rubber seal to expand in the hole. Then connect the bolt’s projecting threaded end with the injection pump and force the adhesive to the rock.
During injection thanks to the expansion shell the rod will reduce the load on the roof caused by injection pressure. After the process of adhesive polimerization is over, the injection anchor starts to play the role of a classic adhesive anchor.
Any adhesives with the required certificates and approvals can be used for injection.

Adhesives used for rock consolidation should have the following properties:
- compression strength > 25Mpa,
- setting time 15’- 25’,
- be effective for dry and damp rock.


AP-KI-ø42 injection bolts have Certificate allowing the product to be marked with the safety mark No. B/1588/IV/2015 issued by Central Mining Institute in Katowice.