Horizon or horizontal mining can be applied to extraction of material from seams of any stratified mineral such as limestone or ironstone, but it is more usually
associated with coal – PArticularly where there are several seams that are inclined or folded and/or faulted.
Horizon mining involves long level roadways (horizons) being driven from the shafts to the extremity of the area to be mined.
The levels of the horizons are chosen to intersect the maximum number of seams the maximum number of times. As the seams are intersected, headings will be driven into the seam so that the desired material may be extracted. This method of mining requires a thorough understanding of the geological structure of the area to be mined so that the level of the horizons can be chosen for optimum results.
This method of mining is popular in modern coalmines with seams worked from several horizons. The considerable capital outlay of driving horizons before production can begin is recouped by the advantage of having long straight level roadways of generous dimensions unaffected by the crushing effect of nearby extraction of the mineral.