Marden Mine

Marden Mine is a mine dug into the Upper Greensand of North Surrey. This has had a long and varied history and undergone a variety of uses. In brief: it started in the mid 19thC as a firestone quarry virtually identical to and contemporary with Godstone Main Series (GMS) just ½ mile to the west. In the late 19thC, like GMS it was used as a mushroom farm, this ceased during the Great War when it appears that the mushroom workers (who were French) returned home to fight – some clearly did not come back.

The site was subsequently reopened for the mining of hearthstone. This is essentially the same rock as was quarried for firestone, but the use was rather different; it was used as a whitening agent for doorsteps and hearths and was in popular use and demand from the late 19th right up to and through World War Two. The style of working is very different; firestone is quarried in large blocks for use as masonry; the passages tend to be square and stable. Hearthstone is mined in lumps using hammers and wedges; the passages tend to be rough and cut along natural joints in the rock, and the end result is usually far less stable than a stone quarry. Note that firestone is quarried as it is a building stone, whereas hearthstone is used as a pigment, effectively making it a mineral which is, by definition, mined. So firestone quarries and hearthstone mines, even though they are after the same bed of rock!

During WW2 the site was acquired by James Gardner (of Chislehurst Cave fame) and partly converted for use as a secure bonded store. The western half of the old firestone quarry was sealed up with heavy duty doors, many of which remain today. Meanwhile, the eastern half was still working as a hearthstone mine and continued until the end of (or just after) the war. This site is at the far end of the firestone outcrop with its highly variable geology and the rock is noticeably softer than to the west; as a direct consequence of this and the less stable methods employed in mining hearthstone, this is the least stable of the Surrey Mines, and parts of the eastern side are already lost forever due to massive collapses.

The site was sealed and ‘lost’ until 1979 when members of Unit Two (later to become WCMS) dug in through the old air shaft and re-opened the mine. The present entrance was built in the early 1980s, and today WCMS look after the site by the good grace of the current landowner. The site is securely gated as it is a bat hibernaculum; however, access is possible during the summer months via WCMS.