Taking the lead on lead (Pb)!

Taking the lead on lead (Pb)!

Historic England writes on the history of the lead industry in the UK.

Approximately 10,000 lead industry sites are estimated to survive in England, spanning nearly three millennia of mining history from the later Bronze Age (c.1000 BC) until the present day, though before the Roman period it is likely to have been on a small scale.

Two hundred and fifty one (251) lead industry sites, representing approximately 2.5% of the estimated national archaeological resource for the industry, have been identified as being of national importance.

This selection of nationally important monuments, compiled and assessed through a comprehensive survey of the lead industry, is designed to represent the industry’s chronological depth, technological breadth and regional diversity.

Nucleated lead mines are a prominent type of field monument produced by lead mining; they consist of a range of features grouped around the adits and/or shafts of a mine. The simplest examples contain merely a shaft or adit with associated spoil tip, but more complex and (in general) later examples may include remains of engine houses for pumping and/or winding from shafts, housing, lodging shops and offices, powder houses for storing gunpowder, power transmission features such as wheel pits, dams and leats. The majority of nucleated lead mines also included ore works, where the mixture of ore and waste rock extracted from the ground was separated (‘dressed’) to form a smeltable concentrate.

The range of processes used can be summarised as:

  • picking out of clean lumps of ore and waste;
  • breaking down of lumps to smaller sizes (either by manual hammering or mechanical crushing);
  • sorting of broken material by size;
  • separation of gravel-sized material by shaking on a sieve in a tub of water (‘jigging’); and
  • separation of finer material by washing away the lighter waste in a current of water (‘buddling’).

The field remains of ore works vary widely and include the remains of crushing devices, separating structures and tanks, tips of distinctive waste from the various processes, together with associated water supply and power installations, such as wheel pits and, more rarely, steam engine houses.

The majority of nucleated lead mines with ore works are of 18th to 20th century date, earlier mining being normally by rake or hush and including scattered ore dressing features (a ‘hush’ is a gully or ravine partly excavated by use of a controlled torrent of water to reveal or exploit a vein of mineral ore).

Nucleated lead mines often illustrate the great advances in industrial technology associated with the period known as the Industrial Revolution and, sometimes, also inform an understanding of the great changes in social conditions which accompanied it.

Because of the greatly increased scale of working associated with nucleated mining such features can be a major component of many upland landscapes. It is estimated that several thousand sites exist, the majority being small mines of limited importance, although the important early remains of many larger mines have often been greatly modified or destroyed by continued working or by modern reworking.

A sample of the better preserved sites, illustrating the regional, chronological and technological range of the class, is considered to merit protection.

Barytes is a vein mineral normally found in association with lead deposits, particularly in the North Pennines. The dominant period of extraction was in the late 19th and 20th centuries and a high proportion of its extraction has come from former lead mines, either by renewed underground workings or re-processing dumps, barytes having been discarded as gangue or waste rock.

The processing of barytes was relatively simple and involved crushing, jigging, drying and grinding at a mill into a powder.

The chief uses of barytes have been as a cheap, inert white filler in the manufacture of paper and paint and more recently it has been used as the basis for barium chemicals.

And now you know!

 

See the entry on the Historic England website – HERE!

 

31st January 2017Comments Off,
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