jenkin

A jenkin is a narrow passage driven horizontally through the body of a coal pillar, typically 4 to 8 feet wide, to allow haulage routes or ventilation in an underground mine. The passage cuts through solid coal that was previously left in place as structural support between worked-out seams or blocks. Unlike a main roadway, which is cut through barren rock or waste, a jenkin sacrifices coal reserve to improve access or air flow.

Jenkies serve practical purposes where the working layout has left isolated blocks of coal or where pillars have grown too thick to drive around economically. The coal removed during jenkin driving is usually extracted as marketable product, offsetting some cost, though the work is considered difficult because of the confined space and the need to support the roof with timber or steel props as coal is removed from beneath it. The passage must be driven with careful attention to the overlying strata, as removing coal from a pillar reduces its bearing capacity.

Etymology and variants

The term is chiefly British, particularly in English coalfields. No agreed standard for minimum or maximum dimensions exists; the word simply denotes a narrow cut through coal rather than around it. Some operators use jenkin interchangeably with coal gate or through coal, though usage varies by region and era. The origin of the word itself is unclear, though it appears in mining literature from at least the 19th century.

Jenkies are now less common in modern mining due to improved mechanization and mine planning that avoids leaving awkward pillars. Historical mines, however, show evidence of extensive jenkin networks where operators adapted to seam thickness, fault lines, or changes in mining method over time. Collapses in old jenkies remain a hazard for rescuers and surveyors working in abandoned mines.