The Lead Mining Process

In the Ullswater Valley, minerals are found in veins running through Borrowdale Volcanic rocks at the head of the valley. The most important veins are of galena, a form of lead sulphide. Galena is often associated with other minerals, such as silver and zinc.

The first challenge for anyone wanting to remove a valuable mineral from a rock vein is to find the vein. Sometimes the vein is visible from the surface but if it is overlain by other materials these have to be removed. Sometimes, early miners used a ‘hushing’ technique, directing water held in storage ponds to flood over the veins and wash away the surface clay and alluvial material, making the ore-bearing veins accessible. In other places, 'leats' or channels were constructed to bring water to the veins. Sometimes the leats could be up to a mile from the vein itself.

Extracting the lead ore

Once you hit the vein, the next challenge is how to get the ore out. In most places, miners dug upwards into the vein, so that the weight of the ore would bring it down to ground level. Then it could be shovelled into tubs and dragged out along the adits.

In some cases, the surrounding earth or rocks would need to be stabilised with arches made from rocks or wooden props. Deep into the mountain side, there may also be a need for ventilation to provide air to the miners. Water seepage was often an issue too, needing constant use of pumps, notably to remove it from workings below the adit that otherwise would flood.

At Greenside, the oldest workings from the 18th century appear as gashes on the fellside at 600 metres above sea level. There were extensive dressing and crushing operations during the 1820s and 1830s on a level area on the valley floor at about 550 metres. A walk around the area today shows collapsed ‘stopes’ – caverns that had been hollowed out by miners underground, but whose surface layer of mud and rocks collapsed inwards when the supporting material was removed. Working in the stopes could be very dangerous because it was impossible to predict if, and when, the rocks above would cave in.

Within the mine itself a complex lattice of interconnecting tunnels and shafts was created to reach the ore-bearing veins. Horizontal levels/adits were connected by deep vertical shafts, enabling the miners to move between the different levels. At Greenside, at the height of its production, there were 22 levels dug horizontally into the mountain.

When the mine was re-opened at the Lucy Tongue level in 1992 to examine the state of the mine (thirty years after its formal closure), many of the levels had collapsed. The metal and wooden supports had buckled, and metal ladders had been prised off the walls as the rocks moved underground. In one area of the shaft the water still shimmers a beautiful turquoise colour, showing off the colour of the copper sulphate.

Originally, ore was removed from the vein by hand, using picks. As the mining methods became more sophisticated explosives were used. A pair of miners, one holding the drill, and the other a hammer, would create a hole in the rock which was then rammed with explosives. Later, this drilling was mechanised, using compressed-air rock drills. These were connected to a Walker's air compressor driven by an electric motor fixed underground, two miles from the generating station. The electric motors were hydro-powered with water brought by a leat from Keppel Cove.

If you are lucky enough to visit the Lucy Tongue level, you will see at one point a series of drill holes in the rock where test holes have been drilled out.

Deep into the mountain along the Lucy Tongue you will finally reach Smith’s shaft that plunges vertically down 500 metres to the bottom of the mine. In all, there are about 4,000 metres of vertical shafts in the mine.

The purpose of processing was to transform raw lead ore extracted from the vein into pure lead. This involved many steps. The first was to wash, sort and dress the ore. Initially the process was very crude, often done by women and children. There was no crushing machinery, and no mechanical sieves. Just hands, hammers and water. The idea was to break the ore into smaller and smaller pieces, and to separate the spoilage - economically unusable material- from the lead.

To facilitate this process water from nearby becks was diverted along leats to supply water holding areas - lagoons. Water played a key role in the process.

Over time, more sophisticated systems were put in place. Water from the lagoons could not only be used to wash the ore, but also to generate electricity for powering pumps to evacuate water; to power crushing machines; and to operate bellows to ventilate the mining shafts with fresh air.

The ore was hammered and broken down into smaller pieces – ideally to the size of a pea. Crushers reduced the material to finer particles, driven by water powered wheels. The crushed rock was sieved and shaken/jiggled, in so-called Hotching tubs, the heavier lead being separated in flotation chambers and collected for later smelting.