hitch

A hitch is a rectangular recess or notch cut horizontally into the side wall of a mine passage, typically at shoulder height or above, designed to support the ends of timber props, lagging boards, or other structural members. The notch functions as a bearing point, allowing timbers to rest securely without requiring additional fastening, and reduces the depth of timber needed to span across the passage.

Hitches are cut into the solid rock or coal face using hand tools or, in modern operations, with pneumatic chisels or small explosive charges. The depth is usually 4 to 8 inches, cut into both sides of the passage to provide symmetrical support. They are spaced vertically at regular intervals, often 3 to 5 feet apart, depending on the height of the passage and the load the timbers must carry. In soft ground or coal seams, hitches may be cut with relative ease; in hard rock, they demand considerably more effort and tool wear.

The primary function is to reduce timber consumption and labour while maintaining roof stability. By lodging timber ends in hitches rather than allowing them to rest only on the floor or against opposite walls, a mine can span wider passages with shorter, cheaper material. This practice was especially critical in underground coal and hard-rock mines where timber was the main support medium before the widespread adoption of steel arches and bolting systems. Hitches also keep timbers elevated and away from pooling water, extending their service life.

Hitches are less common in modern mining, where steel arches, rockbolts, and shotcrete have replaced timber as the standard support system. However, they remain relevant in shallow or old workings, in small-scale or artisanal mining, and in historical mine documentation and repair. The term also appears in quarrying and stone extraction, where similar notches are cut to support temporary structures or extraction equipment.