The site, part of the Yorkshire Klondike, includes the remains of Beldi Hill Low Level lead ore works and mine level situated on the steep sided east bank of the River Swale 3km south of Keld.
The site is laid out on four terraces, partly cut into the hillside, and includes the entrance to an adit, or horizontal mine tunnel, a spoil or waste tip, bouse teams (for storing rough sorted ore), ore crusher, wheelpit and washing and dressing floors for making ore ready for smelting. The site also includes a range of water management features and the low earthwork remains of a large building.
The main water supply for the processing was from the beck known as Oldfield Gutter which passes through the site, with the mine and spoil tip lying to the west and the ore works to the east.
The adit entrance emerges on the uppermost terrace and some of the rails for moving the ore tubs are still in place. Waste from the workings was tipped to the north where the large spoil tip lies spreading out and down to the lower terrace level.
A wide bridge spans the beck which provided access to the bouse teams and also formed a dam to help regulate water supply. To the west of the mine entrance are the remains of a small stone building, possibly a smithy where tools could be regularly sharpened.
The bouse teams are a group of four horseshoe shaped stone chambers, the top of which are level with the upper terrace so that the lead ore could be tipped directly in. To the east of the bouse teams is a chute, cut through the rock, which fed the ore directly to the crushing plant located on the terrace below. The crushing plant had two sets of iron rollers, one each side of a water wheel. Four stone weights for adjusting the space between the rollers survive, two on either side of the wheel pit.
On the next terrace down are a pair of boat shaped, stone tanks thought to be wash kilns or separators. On the lower terrace is a large stone flagged area with flat buddles (for separating ore in a moving current of water) and separating tanks. At the east of this washing floor is a boat shaped settling tank which leads onto a further smaller and slightly lower stone terrace to the east.
On the river terrace between the lower dressing floor and the river are low earthwork banks representing the remains of a structure 6m square with a further structure extending for 10m towards the river. A stone built conduit, now partly buried, leads south westwards from the east of the dressing floors which discharged excess water into the river. At the mouth by the river are traces of a final silt trap, to extract any last residues of ore.
To the west of the site the course of the beck across the river terrace has been substantially widened to form a reservoir up to 12m wide. The reservoir was dammed at the south end by a stone bridge and along the south edge of the river terrace traces of stone revetting are visible.
Throughout the site are drains and leads to channel water to and from the various processes. Extending from the east of the lower dressing floor is a stone revetted causeway leading to the smelt mill at Swinner Gill.
It is not known exactly when the Beldi Hill complex was developed but sources suggest that the mine was driven in 1843 and the mine is certainly shown on the 1857 OS map. The ore works were probably built between these dates and were in use until the early 1880s when the mine level was abandoned because of flooding.