Along the Tunnel Road cutting in Reigate there are a number of caves dug into the hill; they are sand mines that date back to circa 1820 and were used up to circa 1900. The sand had two purposes; for glass manufacture and for scrubbing. When the mining ceased the caves were used for a variety of uses; cordite from Woolwich Arsenal was stored their during WW1, wine merchants stored wine and disposed of empties there, during WW2 it was used as a shelter for locals and people travelling down from London and the caves are used by a local shooting team today.
Due to the high quality of the sand, many locals excavated under their homes to supplement their incomes – which led to many subsidence incidences. The two notable ones are when five cottages disappeared into the ground from a collapse and when the cricket pitch fell through due to another collapse (no one was injured or killed in either incidences).