1. Colliery Closures in the British Coalfield, in particular the Staffordshire Coalfield
2. Geology & Extraction History of the Non-Aggregate Mineral Resources of Staffordshire
David Coxill, SCMC Journal No.3
Staffordshire is a geologically and topographically diverse county occupying some 2,716 square kilometres, ranging from the limestone uplands in the north-east, much of which lies within the Peak District National Park, through the productive farmlands of the Vale of Trent, to the ancient woodlands of Needwood Forest and the Cannock Chase Area of Outstanding Natural Beauty.
It is rich in valuable mineral resources including coal, ironstone, clay, gypsum/anhydite, sand & gravel, limestone, building stone and silica sand, the exploitation of which has taken place for several centuries. This article deals with the non-aggregate resources (excludes sand & gravel and limestone) in the area of the County outside the Peak District National Park.
This is shown in Fig. 8. The oldest rocks in the County are the Stockingford Shales that outcrop as small faulted inliers at Dosthill, near Tamworth. They were deposited during Tremadoc times, traditionally classified as part of the Upper Cambrian but now considered by some authors to belong to the Ordovician. Into these beds have been intruded diorite sills, forming the Dosthill "Granite", at a later date. Silurian strata does not outcrop at the surface, although a borehole sunk at Smestow Bridge, Wombourne, penetrated Wenlock Shales at a depth of about 380 metres.
The Lower Carboniferous is represented by the Dinantian Limestone Series that outcrop in the Peak District National Park and Cauldon Low area in the north-east of the County. Fissures in the limestone have locally been mineralised by copper, lead, haematite and barytes from intruding hydrothermal fluids.
The Upper Carboniferous is divided into the Namurian Series ("Millstone Grit") and the Coal Measures. The Namurian Series was laid down at the start of the Upper Carboniferous, characterised by hard "grit" sandstones, outcropping over a wide area in North Staffordshire, between the northern coalfields and the limestone area of Peak District National Park / Cauldon Low. It also contains a few localised, thin coal seams eg between the Rough Rock Sandstone and Chatsworth Grit. The Coal Measures were deposited in Westphalian times and form the outline of the several coalfields in the County. The Productive Coal Measures (Lower and Middle) are famous for the formation of coal seams, fireclay and ironstone. The overlying Upper Coal Measures are mainly barren of workable coal seams, the exception being the Blackband Formation at the base of the Upper Coal Measures in the Potteries Coalfield where they have been worked. They are largely composed of collectively red marls, mudstones, siltstones and sandstones. They are represented in ascending order by the Etruria Formation; Newcastle Formation in the north and Halesowen Formation in the south; Keele Formation and Enville Formation (possibly of Permian age). Valuable clay deposits are extracted from the Etruria Formation.
Triassic strata consisting of the Sherwood Sandstone Group and the overlying Mercia Mudstone Group outcrop across the majority of the County area and dominates the central region. They provide an important source of crushed aggregate and also contain the Staffordshire Saliferous Beds and Tutbury Sulphate Seam. In the Needwood Forest area is a small insignificant outcrop of Jurrasic strata. Glacial drift and river deposits have selectively produced valuable sand and gravel.
Non-Aggregate Mineral Resources and their Exploitation
There are several individual coalfields from which deep mine and opencast coal has been won. For convenience, their extent, structure and stratigraphy are each discussed in turn.
1. North Stafforshire Coalfield
a) Potteries Coalfield
Geology - The exposed part of the coalfield, centred on the North Staffordshire Coalfield, is triangular shaped and covers about 100 square miles, from Congleton in the north, south-eastwards to Mucklestone and southwards to Moddershall. The southern base of the triangle is irregular, where the Coal Measures dip beneath later Triassic strata and extend southwards to the Swynnerton Fault. To the west, the coalfield is bounded by the Red Rock Fault against the Trias, while the eastern flank is formed by the outcropping of the underlying Namurian Series as the axis of the Werrington antiform (dome) is approached.
The structure within is dominated by two antiforms, the Western and the Werrington, that converge to the northern apex of the coalfield, and the Potteries synform (basin) that lies between them and broadens out to the south. The coalfield is broken up by faults, most notably the Apedale Fault.
Over 50 horizons have been worked for either coal, clay or ironstone in a 2,000 metres thick Coal Measures sequence. The main workable coal seams that have been worked are Blackband, Red Shagg, Red Mine, Clod, Hoo Cannel, Bassey Mine, Peacock, Spencroft, Great Row, Cannel Row, Cahlkey, Bungilow, Bay, Winghay, Blackmine, Rowhurst, Burnwood, Twist, Birchenwood, Moss, Five Feet, Yard, Ragman, Rough Seven Feet, Hams, Bellringer, Ten Feet, Bowling Alley, Holly Lane, Hard Mine, Banbury, King, Crabtree, Ribbon and Two Foot.
History - Early references to coal mines at Tunstall (1282), Norton-in-the-Bog (1316), Shelton (1291) and Keele (1333) indicate that coal extraction has taken place in the Potteries since at least medieval times. These early workings would have been shallow operations from prototype opencast coal sites, bell pits, inclined tunnels (footrails) and shallow shafts.
The number of pits in production steadily increased, supplying the Nantwich salt industry in the 17th century, as well as the local market. With the advent of the Industrial Revolution, the demand for coal increased, primarily from the pottery industry but later also from the iron industry, for coking coals. With improvements in ventilation and the invention of the steam engine for pumping the mines dry, pits were sunk to very deep levels throughout the 19th century.
Some 50 collieries were operating in 1835 and output rose from 1,295,000 tons in 1856 to 3,900,000 tons in 1870. The continued boom in the iron industry in the 1870s led to further expansion but this was curtailed somewhat by the depression of the 1880s. By the beginning of the 20th century, coal was being mined from Stafford Colliery (1873-1968) from a shaft 823 metres deep, the Deep Pit at Hanley at 810 metres, Sneyd at 823 metres and Florence at 792 metres. Output rose to 6,784,000 tons in 1907 and was maintained at that general level until the 1970s.
Pits became bigger but fewer as the century progressed, with the exhaustion of reserves, need for rationalisation during the Great Depression of the 1930s, oversupply in the 1960s, competition from cheap subsided imported coal in the 1980s and 1990s. Coupled with geological problems, this has resulted in only Silverdale Colliery and Hem Heath Colliery of the largest pits remaining open. Even these two pits were temporarily mothballed in the last massive pit closure programme prior to privatisation, now only producing and employing a fraction of their former output and workforce under private control.
A few small drift mines continue to operate in this harsh economic environment on a reduced scale from peak post war production in 1956. Opencast production has been continuous until recently, mainly in the western part of the coalfield. With the completion of coaling operations at the High Lane and Brown Lees opencast sites recently, there are currently no opencast operations coaling in this coalfield.
b) Cheadle & Other Minor Northern Coalfields
Geology - To the east of the Potteries Coalfield, a series of folds have preserved Coal Measure strata in basins, forming the Shaffalong (narrow, north-south trending basin of 2 square miles), Goldsitch/Moss (actually in the Peak Park area) and Cheadle Coalfields. Of these, only Cheadle is significant, being roughly diamond shaped and 18 square miles in area. The Coal Measures are preserved in a symmetrical synform with the strata dipping more steeply to the west. The strata also dips beneath Triassic cover to the south.
The main workable coal seams are Two Yard, Getley, Half Yard, Litley, Four Feet, Dilhorne, Alecs, Foxfield, Mans, Cobble, Rider, Woodhead, Sweet and Crabtree. Only the basal beds of the Productive Coal Measures occur in the small Shaffalong and Goldsitch/Moss Coalfields.
History - Although the Cheadle Coalfield dates back to early times, due to poor transportation, relatively thinner and fewer seams compared to the Potteries Coalfield, it was never fully developed. Production reached 200,000 tons per year in 1875 but deep coal mining ended with the closure of Foxfield Colliery in 1965. Small scale opencast coal sites have been worked until 1994. Production has currently ceased.
2. South Staffordshire Coalfield
Geology - The exposed coalfield is elliptical in shape, extending from the Linley Hills in the south to Rugeley in the north. It is bounded to the west by the Western Boundary Fault and to the east by the Eastern Boundary Fault respectively. The main southern coalfield is separated from the northern Cannock Chase extension by the east-west trending Bentley Faults in the proximity of Walsall.
The County boundary lies just to the north of the Bentley Faults, adjacent to the Wolverhampton and Walsall Metropolitan Districts. The only part of the exposed main southern coalfield that lies within Staffordshire is a small area around the Himley Wood/Gornal area, west of the adjoining Dudley Metropolitan District. North of Cannock, the Productive Coal Measures extend and dip northwards beneath Triassic cover to the Swynnerton Fault, and beyond the two Boundary Faults where they have been downfaulted, also beneath Triassic cover.
The chief seams of the main coalfield in descending order are Brooch, Flying Reed, Thick, Heathen, Sulphur, New Mine, Fireclay Coals and Bottom. Of these, the principal seam is the Thick Coal which is up to 30ft (9m) thick in the Himley/Dudley area. This seam is composed of several individual horizons that have come together.
When traced northwards, the Thick Coal splits up into distrinct coal seams with a gradual increase in thickness in the intervening mudstones and siltstones beneath each coal seam. At Littleton Colliery, near Cannock, the thickness of strata corresponding to the Thick Coal is 52 metres. This seam splitting continues northwards into the North Staffordshire and Lancashire Coalfields where the Productive Coal Measures sequence becomes very thick. The main coal seams in the Cannock Chase Coalfield are the Top, Robins, Bottom Robins, Benches, Wyrley Bottom, Old Park, Heathen, Stinking Yard, Bass, Cinder, Shallow, Deep and Mealy Grey.
History of Cannock Chase Extension - Coal seams lie close to the surface in the southernmost part of the Cannock Chase Coalfield. These were the first to be extracted and early records indicate that small scale mining occurred around Beaudesert from 1298 onwards and at Cheslyn Hay, Easington and Great Wyrley in the 17th century. Mining was first by bell pits and later by shallow shaft mines. These very small scale workings were mainly confined south of Watling Street (A5) to the Bentley Faults.
As these early workable deposits of coal started to become exhausted in the mid-19th century, deeper and more productive mines were sunk to the north of Watling Street in the second half of the 19th century and first quarter of the 20th century.
The years 1860-1880 particularly saw intensive growth in which William Harrison and John R McLean were the pioneers. McLean founded the Cannock Chase Company to sink Uxbridge Colliery at Hednesford in 1852. New sinkings took place at West Cannock, Walsall Wood, East Cannock, Cannock & Leacroft and Cannock Old Coppice in the 1870s, which saw the population of the Urban District of Cannock increase from 2,913 in 1861 to 20,613 in 1891.
The economic depression of the 1880s saw many pits become unprofitable, many were closed and othes sold cheaply. An upturn in the economy led to the resumption in pit sinkings in the 1890s and, in 1905, Littleton came into production. By this time, pits had become quite deep, one shaft at Littleton being 500 metres on its completion in 1902. The tendency of mining to move north and west as the older pits in the south were abandoned continued and, in 1900, Cannock Wood Colliery had 837 underground workers and COnduit Colliery 870 against under 100 in the main South Staffordshire Coalfield. This is refelcted by the figure that 33 pits in Cannock Chase produced as much coal as 276 in the main southern coalfeld.
There were some 20th century pit sinkings apart from Littleton (abortive sinkings had occurred much earlier at this mine). Hilton Main in 1919 and West Cannock No.5 in 1912, but the depression of the 1930s saw many pit closures and declining output. The coal industry was nationalised in 1947, which ended until privatisation in 1995 private owership of all but very small mines employing less than 30 men.
The nationalisation years saw progressive massive pit closures and, with the closure of Littleton Colliery in 1992, no deep coal is mined in this coalfield. Even Lea Hall, opened as recently as 1960, could not escape the intensive pit closure programme of the 1980/90s, closing in 1990 due to heavy faulting. The coal from Littleton and Lea Hall had a high chlorine content which required blending with low chlorine opencasted coals for it to be acceptable to power stations. Now the only productive coaling operation in the coalfield within Staffordshire is the Bleak House opencast coal site.
3. Main Southern Coalfield
This coalfield has been worked from early times, principally for the Thick Coal. With exhaustion of shallow reserves, the coalfield declined rapidly in the 19th and 20th centuries. The shallow mining around Himley Wood saw many pit closures in the 1920s. The only major mine to be sunk this century was Baggeridge in 1912, west of the Western Boundary Fault. Deeper lying reserves were exploited, mainly of the Thick Coal, but also of the subsidary Brooch, Heathen and New Mine seams. This mine worked coal using the pillar and stall method. Only 6ft of the Thick Coal was worked, the remainder being considered too inferior. Its closure in 1968 marked the end of deep mined coal production in this coalfield within present day Staffordshire.
4. Warwickshire Coalfield
The north-western part of the Warwickshire Coalfield, which is fault bounded, just extends into Staffordshire in the Tamworth area. Here the Productive Coal Measures are about 260 metres thick. They contain the following main coal seams Four Feet, Thin Rider, Two Yard, Bare, Ryder, Ell, Slate, High Main, Smithy, Seven Foot, Deep Rider, Deep, Top Bench and Bench. Underground coal extraction has now ceased although potential opencast coal resources exist by the River Anker.
5. Concealed Extensions to the Coalfields
The exposed coalfields represent areas where the Coal Measures have been uplifted, bringing them to the surface. In the north-east of the County, around the Peak District National Park/Cauldon Low area, the Productive Coal Measures have been eroded to expose older strata. Between the coalfields, the Coal Measures, in part at least, have been preserved at depth and are concealed extensions beneath later Triassic cover.
Borehole and seismic data have indicated several deep mine prospect areas where workable coal reserves lie at accessible depths. In their project "Coal 2000", conducted in the late 1970s, British Coal identified three deep mine prospecting areas affecting Staffordshire :-
a) South/East Staffordshire Prospect. The Lichfield Basin, lying between the Warwickshire and Cannock Chase Coalfields.
b) West Staffordshire Prospect. The Stafford Basin, lying between the Cannock Chase, South Staffordshire, North Stafforshire and the East Shropshire Coalfields (Coalbrookdale and Forest of Wyre).
c) The Cheshire Basin. Lying between the North Staffordshire, North Wales and South Lancashire Coalfields.
The most promising prospect was the Park Project, immediately east of Stafford, which proved the interconnection of the North Staffordshire and Cannock Chase Coalfields. It was intended to sink a colliery at Hopton in the 1980s but the project was abandoned because of the high chlorine content of the coals. Nevertheless, this is a proven reserve of 300 million tonnes, 100 million of which could be extracted from 10 workable seams.
B) OIL & NATURAL GAS
Petroleum has been discovered to impregnate coal seams in the Potteries Coalfield at Hanley Deep Pit and Trentham Colliery but wild cat drilling has never discovered commercially retrievable deposits in the County. Exploration for natural gas, either on its own or in connection with potential oil traps, has been equally fruitless to date. However, there is a greater possibility of success where future exploratory drilling is concentrated on the exposed and concealed extensions to the coalfields to extract methane directly from coal seams. Oil has been experimentally extracted from oil shale in and above the roof of the Red Shagg Ironstone and in the roof of the Cannel and Great Row coal seams of the Potteries Coalfield. This remians a potential resource for the future.
Minestone mainly consists of a variable mixture of burnt and unburnt colliery waste composed of mudstones, siltstones, sandstones, ironstones and ash where it has been converted by spontaneous combustion. The Minestone Executive was established in 1971 by the then National Coal Board to direct and control its commercial exploitation.
The traditional uses for minestone include common fill, land reclamation, sea and river defence, road and rail embankments, brick and aggregate production. The demand for minestone is therefore linked to the construction industry. The brick industry no longer has any block making light aggregate plants utilising minestone in the UK because the market demand is now for much higher quality products. Colliery spoil from Baggeridge Colliery (1912-1968) was formerly used to make low quality bricks by Baggeridge Brick PLC. In recent years, colliery spoil has been successfully used as an ingredient in a rock paste for infilling disused limestone mines in the West Midlands.
Where Minestone is locally available, it can often compete effectively in direct cost terms with primary fill materials, although where borrow pits adjacent to construction sites are used, the transport costs of any imported fill are a major barrier to overcome. Problems with variable quality and wet weather placements can lead to its exclusion from contract specifications and can sometimes involve additional costs. With the presence of so many former colliery waste tips in the coalfield, minestone is a potential resource where environmental safeguards permit its excavation.
Nodules and bands of ironstone, often as distinct horizons, occur within the Coal Measures sequence. They are normally continued to the Productive Coal Measures, although in North Staffordshire they are also developed in part of the Upper Coal Measures known as the Blackband Group. In the South Staffordshire Coalfield the main seams are Lambstone & Brownstone, New Mine [Editor's Note - in the south-east "Mine" was the old name for ironstone itself and possibly it was the same here], Pennystone, Poor Robins, Gubin & Balls, Blue Flats, Silver Threads and Diamonds. In the Warwickshire Coalfield they are represented by the White, Black, Brown and Balls seams.
In the North Staffordshire Coalfield the main seams are Halfyards, Red Shagg, Red Mine, Gubbin Mine, Cannel Row, Wood Mine, Pennystone, Deep Mine, Chalky Mine, New Chalky, Hanbury Measures, Ragmine, Priorsfield, Knowles, Black Mine, Brown Mine, Rowhurst or Ash and Burntwood or Little Mine. These ironstones are composed of the mineral siderite (iron carbonate), although those horizons in the North Staffordshire Coalfield including and higher than the Burntwood Seam became progressively more carbonaceous in content.
History - The North Staffordshire Coalfield is rich in ironstone. It is believed t have been worked at Holditch by the Romans in the 2nd century AD. Records of it being worked date back to medieval times but it was not until the Industrial Revolution that output and demand expanded rapidly. The mineral was worked from progressively deeper mines that normally also extracted coal.
Output in North Staffordshire was almost 2 million tonnes per annum in 1884 but had dropped to below 1 million tonnes per annum in 1902. The importation of cheaper foreign ores in the 20th century led to a steady decline in production which had ceased by the time the coal industry was nationalised.
Ironstone mining was also important in the southern part of the South Staffordshire Coalfield in the 19th century but likewise declined this century, ceasing about 1930. It was never of significant importance, however, in the Cannock Chase Coalfield. Ironstone was once extensively mined in the Glamcote and Wilnecote area of Tamworth and production continued into the present century.
E) OTHER METALLIFEROUS DEPOSITS
The south-western part of the Derbyshire orefield extends into the Peak District National Park and marginally into administrative north-east Staffordshire in the vicinity of Weaver Hills and Oakamoor. Here, some of the fissures in the Carboniferous Limestone have been mineralised, often as steeply dipping vein lodes of copper, haematite, lead, zinc and barytes.
The metal mines recorded in Staffordshire in this area are Ribden (Ingleby's, Gilbert's, Hodgkinson's and Swallow Shafts), Old Shafts, Thorswood and Star shaft and level near Oakamoor. Extraction in this area is periodically recorded from the late 17th century until the 1830s.
Occasionally, ore deposits have been discovered outside the main orefield but these are rarities. In 1873, a shaft sinking at Fair Oaks Colliery came across a lead (galena) vein and a copper deposit was worked at Shore Hill, both in the Cannock Chase area.
F) IRONWORKS SLAG
Tips of former ironworks can provide a very tough slag varying to a mixture of furnace ash and slag. This has been used in the manufacture of cement blocks and these tips have been quarried in recent years at Apedale. Other similar tips remain to be worked, although development would be restricted by environmental constraints, particularly as some have already been landscaped and/or built upon. Blasting sand from furnaces can be used as an aggregate where it is found in such tips.
Clays for the manufacture of bricks, tiles, pottery and pipes have chiefly been exploited from the Productive Coal Measures and Etruria Formation, particularly in the Potteries. Seat earths that lie directly beneath coal seams are no longer commercially exploited from collieries. Limited quantities are extracted from surface workings, on occasion in conjunction with opencast coal workings.
In the Potteries Coalfield, mudstone and siltstone horizons have been worked between the Spencroft and Hoo Cannel Coal seams extensively between Tunstall and Longton. Other horizons have been worked, mainly between the Twist band Bungilow coal seams. Until recently, Birchenwood Quarry produced bricks from Productive Coal Measures clays.
The most favoured source for brick clay is the soft Etruria Formation of the Upper Coal Measures, which has been extensively worked in the coalfields. In the Potteries Coalfield, the Etruria Formation has been sub-divided into three divisions recently by the British Geological Survey. The Lower and Middle divisions are the most valuable, although the Lower contains thick sandstone horizons. The Upper division is less valuable because it contains calcareous veins, pellets and nodules that can burst during firing, particularly at its top.
A similar classificaiton of the Etruria Formation has not been carried out for the South Staffordshire and Warwickshire Coalfields. In the area around Cheslyn Hay, west of Cannock, the Etruria Formation contains thick sandstone units and a high lime content. However, unlike in the north, the lime here is finely disseminated in the clay, rather than forming discrete concentrations, and is apparently suitable for brick making. A fundamental problem is that large tracts of the outcrop of the Etruria Formation has been built upon, thus sterilising this valuable resource.
The Newcastle and Radbrook Formations are a potential resource for brick clay, for blending purposes at least. At Willoughbridge Wells, near Market Drayton, a small quarry currently works clay from the Radbrook Formation. On a localised basis, clays have been periodically worked from small, shallow quarries in the Mercia Mudstone Group. Their relatively inferior clay mineralogy compared to the Etruria clays, however, has prevented extensive development of this widely outcropping group in Staffordshire.
H) SHALES FOR CEMENT
In the proximity of Cauldon Cement Works, a low sulphur turbiditic mudstone in the Namurian Series is currently worked to be used in the manufacture of cement at the nearby works.
I) SILICA SAND
Silica sand is an industrial term for material with a high proportion of quartz, which is marketed for purposes other than for the construction industry, eg glass making and foundry/moulding sand. It can be produced from both crushed sandstone and unconsolidated sand. Current, and most of the past, production of silica sand in Staffordshire has been from the Rough Rock Sandstone horizon of the Namurian Series. This horizon is up to 30 metres thick and contains up to 15% clay and over 0.5% iron oxide.
At Moneystone Quarry, Oakamoor, crushing, grinding, fines rejection and acid leaching improve the quality sufficient for the silica sand to be used in glass manufacture, as a silicate in soda manufacture and fillers in asbestos cement. It is still worked on a small scale at Hurst Quarry, Biddulph, in this same horizon and here the silica content is 98.8%. The Wildmoor Formation of the Triassic has in the past been worked in the Wombourne area as a source of moulding sand used in the foundry industry.
Whetstone is a fine-grained, very hard, well sorted sandstone with a high silica content of up to 95%. At Gillow Heath, Biddulph, it forms a 1.4m to 2.1m thick seam near the base of the Lower Coal Measures , lying within a 158m thick sequence of mudstones, siltstones and sandstones between the King and Crabtree Coal Seams. In the vicinity of Gillow Heath, the Productive Coal Measures form a south-south/west plunging synformal syncline between two east-west trending faults. The whetstone seam outcrops on both the east and west limbs of this synform, dipping towards its axis.
The peculiar property of whetstone is that, after grinding, it has a glass-like smoothness and does not scratch the surface of the material it is being used on. It has also been used in the printing industry to smooth down copper plates and can also be used as an abrasive stone for sharpening. Whitestone, a similar sandstone which is also found at Gillow Heath, was used for high quality smoothing, known as honing.
History - The extraction of whetstone has been recorded from the mid-19th century, either at outcrop or from shallow underground workings, normally in conjunction with working coal and clay seams. Small quantities of whitestone have also been produced. Extractive operations had ceased by the 1980s. During this century, the following mines have been operational - Mow Cop (1927-28), Hill Lane, Freehay, Hollington (1930), Park Lane, Audley (1930), Gillow Heath (c.1870-1970s?) and Oxhay (?-1950).
K) IGNEOUS ROCKS
Diorite has been quarried at Dosthill, commonly known as the Dosthill "Granite", for roadstone but this has not taken place for some years. The Swynnerton and Butterton dykes of North Staffordshire are too narrow in width in themselves to be a valuable aggregate resource.
L) BUILDING STONE
Extraction of snadstone for building purposes has taken place in Staffordshire since early times. The most notable horizon to be exploited is the Hollington Stone (red, white and mottled varieties) in North Staffordshire. This belongs to the Hollington Formation at the top of the Sherwood Sandstone Group.
The Hollington Stone is highly prized by stone masons throughout the country as a freestone and has been used in the construction and maintenance of churches, cathedrals and other public buildings. Current extraction of the stone takes place at a few quarries in the Hollington/Cheadle area but none now work the "White" variety.
Other horizons have been worked in the lateral equivalents to the Hollington Formation at Beech, Fulford, Chapel Chorlton, Penkridge, Hopwas and Brewood. Small scale underground pillar and stall working at Beech Cave provided the stone to build Trentham Hall in the 17th century. Another limited underground working at Little Haywood, near Stafford, took place in the mid-19th century.
The Chapel Chorlton Stone, quarried at Fulford and Chapel Chorlton, is white and free of iron stains. It was once in great demand but by the 1830s gave way to the superior Hollington Stone. A small mine in the Kent Hills, near Audley, worked the Chester Pebble Beds ("Bunter") in the early 20th century but this was for aggregate, not building stone.
The hard sandstone horizons of the Namurian Series have been extensively quarried for building stone on the flanks of the North Staffordshire Coalfields. Only a very small quarry in the Minn Sandstone at Hollins Farm, near Leek, now utilises sandstone for building and ornamental purposes from these beds. Two underground mines working the Namurian Series are recorded in the 19th century, at Mow Cop and Longnor.
In the past, limited quarrying of snadstones in the Coal Measures has taken place, eg Ten Feet Rock of the Productive Coal Measures, Hanchurch Sandstone of the Newcastle Formation and the red sandstones of the Keele Formation. Only the latter have produced good building stone, other sandstones generally being too soft.
1. Gypsum & Anhydrite
These are two natually occurring mineral species of calcium sulphate that are found in Staffordshire within the Tutbury Sulphate Seam of the Mercia Mudstone Group, Upper Triassic. The Tutbury Seam is up to 4 metres thick but is not uniform, consisting of discontinuous masses of gypsum/anhydrite, separated by silty mudstones, with mior amounts of alabaster (a very pure form of gypsum) and rock salt.
In Staffordshire, the Tutbury Seam appears to lie in a synformal syncline known as the Needwood Basin, plunging to the south-west. The axis of the syncline is situated approximately at Tatenhill Aerodrome, trending in a west-south west to east-north east direction. It has been mapped as outcropping from near Hound Hill to Tutbury, dipping generally southwards.
The current Fauld Mine works the Tutbury Seam on the southward dipping limb of the Needwood syncline. The mine is affected by an east-west trending faulted monocline between Hanbury Park Gate and Home Farm, which takes the Tutbury Seam to its deepest levels on a north-south line through the mine workings.
As the mine progressed southwards to greater depths, it was found that the Tutbury Seam changed in composition and contains an increasingly higher proportion of anhydrous gypsum known as anhydrite. The difference between the two minerals is whether or not the calcium sulphate has bee hydrated. Shallow deposits that have come into contact with groundwater will become hydrated forming gypsum, while anhydrite contains no water and is consequently found at deeper levels.
On the southern limb of the Needwood syncline, the Tutbury Seam has been mapped as outcropping from Horninglow, west of Burton, to Tatenhill village. This outcrop dips north-west towards the axis of symmetry extending to Tatenhill Aerodrome. The Tutbury Seam is recorded at shallow depth further west near Chartley at Normanswood Farm, just east of Stowe where it was formerly worked (1930s-1956).
History - Gypsum has been mined in the vicinity of Fauld and Hanbury for many centuries. The earliest extraction appears along the outcrop where bell pits were sunk. The second rim of the arch of the west door of the Norman Tutbury Church is constructed of alabaster. It was not until the second half of the 19th century, however, that large scale underground mining commenced. The most westerly working was Draycott Mine, which closed around 1939. Underground mining has taken place at Fauld since 1868. It commenced when both J C Station & Co and Peter Ford & Sons Ltd established mines to provide raw materials for the increased demand for building plasters.
These continued to operate separately, even after 1936 when both companies were incorporated into the British Plaster & Boards Company. The mines became united as the Faulds Mine in 1944 with the construction of a new access adit. In that same year a detonation in an armaments store, located in an abandoned north-east sector of the mine, led to the ignition of 3,500 tonnes of high explosive bombs. Over 100 people were killed and a large surface crater remains in the wooded escarpment of Stonepit Hills. Only part of the seam is worked but production reached 521,845 tonnes in 1970-71, although it has since declined. Changes in the nature of the Tutbury Seam led to a changeover in production in 1989 from gypsum for bagged plaster to anhydrite as a retarder for the cement industry.
Rock salt or halite occurs as saliferous marls within the Mercia Mudstone Group. Their top lies 107m below the Tutbury horizon and salt bearing marls are known to occur within the underlying 61m. In the Stafford area, they form discontinuous lenses rarely exceeding 12cms thick in a gradational zone 50-65m thick, extending from 150m from the base of the Mercia Mudstone to about 50m below the surface. Here the Mercia Mudstones form a gentle, north-north/west to south-south/east trending synfomral syncline. The north-south trending Hopton Fault uplifts the Sherwood Sandstone against the Mercia Mudstone about 1 mile east of Stafford and forms the limit of the salt deposits to the east.
The outcrop of the Mercia Mudstone extends northwards to Stone, to the west for about 8 miles and to the south-west for about 14 miles, but little is known of the extent of the salts other than they occur in the central axial (deepest) part of the synform. Just north of Marston village, 3 miles from Stafford, only 15cms of salt was found in a borehole, while at Ivetsy Bank, 10 miles south-west of Stafford, only thin laminars 3mm thick are recorded in the middle of the gypsum veins. Thin beds of salt are recorded from boreholes around Stafford. It would appear that the salt beds are relatively thin and have no wide distribution around Stafford, their greatest and thickest extension possibly being to the north-west and west of Stafford. Brine occurs in a natural salt well south of Stafford on the banks of the River Penk.
The Mercia Mudstone reappears east of the Hopton Fault and has an extensive surface outcrop extending beyond the county boundary with Derbyshire to the east and to the Cheadle Coalfield to the north. Apart from recorded brine streams at Weston-on-Trent and Shirleywich, deposits of rock salt have been proven between depths of 95-162m at Chartley Castle, 6 miles north-east of Stafford, and at depths between 175-213m just north of Abbots Bromley. The extent of these beds is unknown but it is possible that they occur as a thin deposit under a wide area between Weston, Uttoxeter, Abbots Bromley and Needwood Forest.
The salt beds are approximately equivalent to the Upper (Wilkesley) Halite in Cheshire, although two separate salt horizons occur there as opposed to the one around Stafford. Rock salt is a soluble material which naturally dissolves into brine when it comes into contact with circulating ground water, forming a "wet rockhead" horizon. Natural solution at this horizon results in a zone of permeable residual broken strata being formed where the mineral has been dissolved, causing collapse and leading to surface subsidence.
In the case of the Stafford Basin, natural solution has also occurred westerly adjacent to the Hopton Fault, where freshwater from the Sherwood Sandstone has leached out the mineral in a 1km wide zone westerly parallel to the fault. The "wet rockhead" horizon lies at a depth of 55-90m beneath Stafford, gradually extending westwards. Former brine pumping operations accelerated this leaching process by drawing in freshwater from adjacent areas that dissolved the salt, causing voids to form, often along fissures in the mineral deposit. The resulting inherent instability caused collapse and upward migration of the voids that caused subsidence features at the surface, forming linear "brine runs". The Cheshire Saltfield extends just into the north-western corner of Staffordshire, around the Betley area near Madeley.
History - Brine springs have been referred to in the 17th and 18th centuries at Weston-on-Trent, Ingestre and Chartley, north-east of Stafford. In 1873, the salt produced at Shirleywich and Weston-on-Trent totalled 3,750 tons but production ceased at Shirleywich at the end of the century and at Weston-on-Trent in 1901.
Brine was discovered at Stafford Common, just north of Stafford town, abut 1881 in a boring for water put down by Stafford Corporation. The first boring for brine started about 1887 and production commenced in 1893. Production rapidly increased to 80,000 tons of salt per year in 1914, before declining until just before World War II when it started to increase again.
In 1948 four companies, subsequently amalgamated as British Soda Ltd, were pumping here as well as ICI. Production reached 72,000 tonnes in 1947 and increased further to 95,000 tonnes by the early 1960s. ICI withdrew in 1969. Subsidence from brine pumping had been reported since 1948 but it was becoming a more serious problem after 1964.
This led to Lotus Ltd bringing an action in the High Court alleging that damage to their shoe factory had been caused by subsidence resulting from brine pumping. British Soda Ltd were ordered to cease production from August 1970. It is estimated that by this time a total of 5 million tonnes (2.25 million cubic metres) of rock salt had been extracted as brine from beneath Stafford.
David Coxill, SCMC Journal No.5
It is no secret that the decline of the coal industry has taken place throughout the country and not just in Shropshire. The number of pit closures per year of nationalised mines is shown in Figure 1. In 1997, there were just under 30 deep mines, excluding small drift mines. Essentially, the problem has been of over-supply which has led to massive pit closures under both Labour and Conservative governments.
Number of Colliery Closures under Nationalisation 1947-1994
|TOTAL = 1,111|
Staffordshire has several coalfields, notably the Potteries, Cheadle, South Staffordshire and the part of the Warwickshire Coalfield that extends into Tamworth. This has substantially greater reserves and historic output than Shropshire but Silverdale Colliery is the only remaining major deep mine. The closure of the major mines since 1947 is shown in Figure 2. No major political party can therefore claim to have favoured the coal industry more than the other.
Closure of Nationalised Collieries in Staffordshire
|Alvecote (merged with North Warwick)||May 1951|
|Berry Hill||Apr 1960|
|Cannock Chase No.3||1959|
|Cannock Chase No.8||Jan 1962|
|Cannock Chase No.9 (merged with Cannock Chase)||1951|
|Cannock & Leacroft (merged with Mid Cannock)||Sep 1954|
|Cannock Wood||Jun 1973|
|Chatterley Whitfield (merged with Wolstanton)||Mar 1977|
|Coppice (Cannock Chase)||Apr 1964|
|Deep Pit (merged with Wolstanton)||Feb 1962|
|East Cannock||May 1957|
|Grove (merged with Wyrley No.3)||Jan 1952|
|Hem Heath||May 1996|
|Hilton Main||Jan 1969|
|Lea Hall||Dec 1990|
|Mid Cannock||Dec 1967|
|Nook & Wyrley||Jun 1949|
|Sandwell Park||Sep 1960|
|Sneyd (merged with Wolstanton)||Jul 1962|
|Walsall Wood||Oct 1964|
|West Cannock No.1 (merged with Littleton)||Sep 1958|
|West Cannock No.2 (merged with West Cannock No.5)||Jan 1956|
|West Cannock No.3||Dec 1949|
|West Cannock No.5||Dec 1982|
|Wimblebury (merged with West Cannock No.5)||Dec 1962|
|Wyrley No.3 (merged with Mid Cannock)||Jun 1963|
|Yew Tree Drift||Apr 1950|