SECTION 460:15-1-26. Permanent roof support

(a)   Roof bolts, timbers, cribs, steel arches, trusses, linings and concrete abutments may be used for permanent roof support.

(1)   Roof bolts shall be installed according to an approved plan and may be either:

(A)   Expansion type anchor;

(B)   Resin bolts; or

(C)   Other methods approved by the Department of Mines.

(2)   Bolts shall be a minimum of forty-eight (48) inches in length and installed on not more than five (5) foot centers unless a shorter bolt and greater spacing is approved by the Oklahoma Mining Commission.

(A)   All bolts shall be used with a metal bearing plate a minimum of thirty-six (36) square inches.

(B)   Wooden header boards or timbers used in long life openings of a mine must be pressure treated to avoid rot and decay for the action life of the mine. (Long life shall mean three (3) years or longer).

(3)   Resin bolts, also called "glue bolts," shall be installed according to manufacturers recommendations. The glue which consists of resin and a catalyst must be completely surround the bolt and fill the drilled hole.

(4)   All roof bolts shall be installed as soon as possible after the roof is exposed but before the top is allowed to sag.

(5)   Timber used to support the roof must be solid, free from defects, and square on both ends. The diameter of the post must be one (1) inch for each fifteen (15) inches of length with a minimum of four (4) inches. When timbers are used to support the roof a cap block not less than two (2) inches in thickness is placed between the roof and the timber. The cap block must be not less than four (4) inches wide and twelve (12) inches long. No more than two (2) wedges shall be used between the timber and the cap board to ensure a tight fit. Footers may be used to prevent the timber from sinking into soft floors. If footers are used they shall be limited to no more than two (2) per timber.

(6)   Crossbars used to support the roof must have a cross- sectional area not less than twenty-four (24) square inches and a minimum thickness of three (3) inches. Crossbars must be solid, free from defects, and straight.

(7)   Cribs used to support the roof must be of wood having flat parallel sides. In no case should the crib be less than thirty (30) inches square.

(8)   Other approved roof control materials and methods may be used on approval by the Department.

(b)   Temporary supports will be used before and during the installation of permanent supports according to an approved plan and to hang line curtains to the face. Temporary supports shall be used with a cap board and installed on not more than five (5) foot centers. Longwall mining will use chock or shield supports or other approved methods.

(c)   Adequate roof support materials shall be stored inside the mine readily accessible to employees and will conform to manufacturers recommendations. Resins not used before the expiration date shall be removed from the mine.

(d)   Each operator shall adopt a roof control plan suitable to the roof conditions and the mining plan and will address haulageways, travelways, escapeway and working places. Roof bolts shall be anchored a minimum of twelve (12) inches in the stronger overlying strata. Test holes will be drilled to determine the length of the bolt needed to achieve minimum anchorage.