Longsplatt Quarry or Long Platt Quarry is located near the golf course just to the north of the main road between Kingsdown and the B3109. The quarry was opened as an open-cast working by the Northey Stone Company Ltd. in 1890. The slope shaft was later added that allowed the extraction of Bath stone from underground and the quarry then employed four underground quarrymen with another twelve men working in the surface stone yard. Maps, photographs and drawings show this stone yard as substantial in size with stone-built stables, offices and a horse-gin to pull the extracted stone to the surface. In 1897, the quarry was leased to the United Stone Firms Ltd. run by James and William Turner from Cardiff. However, ten years later in 1907, the viable stone reserves were worked out and the enterprise closed in 1920. The surface area was then made fully residential.
The surface features of the quarry are now landscaped. There was an air shaft, which is now built over at ‘The Quarry Edge’ and a 45-degree slope shaft with steps. This inclined shaft, in the back garden of ‘The Old Quarry’ residential property, is also backfilled. Enthusiasts worked at reopening the slope shaft in 2007 and exposed the old arched entrance before access was lost. It is reported that waste oil was dumped in this quarry prior to being sealed.
To the east in the fork of the road was an open quarry with little evidence remaining today.