In geological terms, chert is classified as a mono-minerallic rock, a fine-grained, flinty silica most commonly found in veins in the uppermost beds of the limestone sequence. Chert was worked into tools in prehistoric times, easily shaped by chipping off flakes to produce sharp edges. Scrapers and awls have been found at a Mesolithic site at Stoney Low, Sheldon.

The most useful role for chert was recognised about two centuries ago for the grinding of calcined flint, used as a whitening agent in earthenware manufacture. In 1772 the potter Josiah Wedgwood recommended Derbyshire chert as a major improvement over granite millstones, which left annoying black specks in the pure white flint. In a Report on Mines and Quarries in Midland District (1897), Stokes describes how chert was ‘of special value for china works where the large blocks are used as millstones made to revolve round and upon a floor paved with the smaller blocks grinding away the chertstones.’

Blocks of Derbyshire chert were initially taken into Yorkshire and Staffordshire by packhorse or cart but from 1793 considerable quantities went by road to Cromford Canal for shipment to the Potteries. In due course the stone was despatched by rail.

Chert was also known as hornstone or petrosilex in the Peak. Although black, and black and white, chert occurs, the white ‘china stone’ variety was found in only a few worthwhile deposits. Major extraction took place in Bakewell at Holme Hall and Holme Bank Mines and Pretoria Quarry, also from pits west of Great Longstone. Smaller mines and quarries existed at Bakewell, Ashford, Masson Hill, Bonsall and Over Haddon pastures.

PITS, QUARRIES & MINES

Numerous records concerning the Longstone chert industry are contained in About a Derbyshire Village (Wright). A reference of 1784 mentions the sum of 6s 9d paid to Samuel Furniss for ‘Getting Chert Stone at 1s 6d pr Day’. Another entry reads: ‘Agreed with Saml Ashton & Jos Garrot to Get Chert Stone for me upon Scrater at 1s 6d per tun’. Costs are shown for gunpowder and for delivery from Longstone chert pits to Chesterfield Wharf, Cheddleton, Gyte Moss, Longnor Bridge and on to Leek. Transport to Cromford and Buxton Moss appears in early 19th-century entries. A trade directory of 1900 names William Millington as a chert merchant at Great Longstone but he is not listed in subsequent directories.

The last two operational chert mines in Derbyshire were the Pretoria Mine and Holme Bank Mine, both at Bakewell. Pretoria opened in 1902. Access was from adits in a quarry at Bank Top and the steep workings extended beneath the road to connect with the earlier Greenfield shaft. The chert bed lies on a 1 in 3.7 gradient and the mine was subject to flooding in severe winters. Illumination was by mains electricity in addition to carbide lamps carried by the miners.

The chert bed was on average 9 ft (2.7 m) thick, though up to 18 ft (5.5 m) in places. It was extracted by removing the underlying limestone so that the chert fell under its own weight. A hoist powered by compressed air loaded it onto flat wagons, drawn to the surface by compressed air winches along a 1 ft 6 in (46 cm) gauge railway. The ‘waste’ limestone was built up into substantial roof supports.

Between the wars the number of employees, which in 1905 totalled 38, fell to about a dozen and by 1964 was reduced to four, only two of whom worked underground. Commercial output from Pretoria ended in 1968/9.

Early 19th-century extraction at Holme Bank was from quarries but commercial mining was in place by 1867, when the site was known as Bakewell Chert Mine. Later it was also referred to as Smith's Mine, after the owner. The workings consisted of an extensive system of passages with eight entrances.

LONG HOURS UNDERGROUND

In 1892, an account of a visit to Holme Hall and Holme Bank Mines was published in the Derbyshire Advertiser. The owner of Holme Hall, Mr Alsop, had a major problem on site at the time: ‘The water, which had since the opening been a great preventative to the successful working of the mine, at length gained the mastery and, notwithstanding the employment of heavy and costly machinery, caused the men to retire from the place.’

By contrast, Holme Bank Mine, the property of Messrs Smith of Burton-on-Trent, was completely dry throughout. The newspaper reporter was given a lighted candle and taken by a workman to one of the work faces, over a quarter of a mile from the entrance. About 40 men were labouring by candlelight, many engaged in cutting up a 20-ton block of chert recently ‘blown down’ by gunpowder or dynamite. Broken up into a manageable size, the stone was removed on wheeled trucks drawn on rails by small ponies.

Blocks weighing 100 tons were occasionally blasted free and although the supply was good, the demand was even better, with large orders arriving from Scotland as well as the Staffordshire potteries. Great piles of chert were normally stocked in the yard of Bakewell railway station but 1892 was such a good year that these were almost used up.

In view of the flourishing state of the industry, the reporter was highly critical of the 17 or 18 shillings (85-90p) a week paid to the hard-working miners. Some had 25 years’ experience and all worked long hours underground. ‘What would a collier think of this?’ asked the visitor. ‘Wouldn’t he strike hard and very often until it would be at least doubled?’

In 1925, 41 men were employed but 20 years later only 21 were at work. Approximately half worked underground. Between the two World Wars, mining broke out on the surface, enabling the chert to be quarried alongside limestone. In its later years Holme Bank met a considerable demand for poultry grit. The mine closed between 1959 and 1961 but a block-making plant, trading as Smith’s Runners, remained in operation, using existing supplies of chert.

In recent years the few underground visitors to Holme Bank Mine have included cave divers, using the clear subterranean waters for training purposes. Almost 10 years ago the Peak Park Planning Board granted permission for the mine to be opened up to visitors but this plan has so far not materialised.

Exhaustive research into the use of local chert was carried out in the late 1990s by Roger Flindall, working with the then owner of Holme Bank Mine, Gordon Bowering. (Published as ‘Hard Times: A History of the Derbyshire Chert Industry’; Peak District Mines Historical Society Bulletin, Summer 1998.)

© Julie Bunting
From "The Peak Advertiser", 16th October 1995;
Updated 11th March 2005.