Bale site overlooking Arkengarthdale

This is the process of converting the ore into metal in a furnace.

The early miners smelted at a bale, which is a wind blown furnace, consisting of a clay lined, dish shaped depression in the ground, with an outlet in one side for the molten metal. Bales were usually built in elevated places to take full advantage of the wind.

From the 1570s, it became usual to smelt the ore in smelt mills, which are more commonly encountered. These are usually placed near to important dressing floors and often contain the remains of ore-hearths and a waterwheel pit, which drove bellows to increase the heat of the fire. There will usually be a heap of slag, the refuse from the process nearby.

From the mid 19th century most smelt mills had long flues, extending up the hillside many hundred metres to a terminal chimney. A few mills had condensers built into their flues to aid deposition of lead particles in the flue gases.

The Smeltmill flue at Grassington Cupola mill is 1795m long. This allowed the smoke from the furnace to be cooled and any contained lead to condense out on the sides of the flue.

Old Gang Smelt Mills complex, Hard Level Gill, Swaledale.

Part of the Old Gang Smelt Mills complex, Hard Level Gill, Swaledale.

Ore-hearths burnt kiln dried wood (chop wood), peat and a little coal. The remains of open sided peat stores can be found at many Swaledale smelt mills. The molten lead, from the hearth, was cast into ingots, called pieces or pigs, which weighed from one to one-and-a-half hundredweights.

Peat Store, Old Gang Mine, Swaledale.

Surrender Smelt Mill, Swaldale.

Flue - Cupola Mill Grassington, Wharfedale, showing one of the access points from where the flue could be swept to recover fume lead