Plump Hill Dolomite Quarry is one of many abandoned excavations in the Forest of Dean, last used in the early 1900s for extraction of limestone, when it was linked by a short tramway to a limekiln on the opposite side of the access road, the main route between Cinderford and Mitcheldean. Today the road (now the A4136) is unchanged, the limekiln long since removed, and the quarry overgrown around the edges though open in the middle, and here a varied assortment of limestone grassland plants have become established, on account of which the quarry was declared a nature reserve, in 1982.
Autumn ladies tresses is the most unusual plant, a small orchid that blooms in August and September, while other notable species include large thyme, white horehound and bogbean. Most plants grow on the grassy floor of the quarry, a flat area a little way below the level of the road; quite a sheltered place, with a south-facing aspect, shielded by cliffs on the other three sides. Those to the east and west are relatively low and entirely covered by undergrowth but the northern cliff is taller, up to 100 feet, and still mostly bare rock. Views are quite extensive to the southeast, across the Severn valley towards the edge of the Cotswolds.
The nature reserve is identified only by a small notice at the southeast corner beside one entrance, a narrow passageway between a hedge and some trees, liable to become completely overgrown, in which case an alternative way in is about 100 feet west at a larger gap in the bushes. There is parking for a couple of vehicles on the opposite (south) side of the road, at the start of a short, private lane. The accessible part of the reserve is relatively small, and it only takes at most 20 minutes to explore; the remainder comprises the cliffs, the thick brush at the base, and a mix of trees, bracken and hawthorn on the high ground to the north and west. Some of the smallest-flowered species are concentrated on low mounds, possibly anthills; they include field madder, lesser trefoil and thyme-leaf sandwort.