Wet Earth Colliery

Wet Earth Colliery was a coal mine in the Manchester Coalfield, in Clifton, Greater Manchester. The colliery site is now the location of Clifton Country Park.

Matthew Fletcher was enlisted by John Heathcote to help sink a new shaft at what was to become the Wet Earth Colliery. The workings were troubled by water ingress from the River Irwell via the Pendleton Fault, leading Heathcote to close the pit in 1750.

The problem of removing the water came to the attention of James Brindley. He initially suggested a scheme using a Newcomen pumping engine, but then proposed a revised scheme using water power. However, there was no head of water on the site to power a pump, and the pithead was 23 feet (7 m) above the level of the River Irwell, about 400 yds away.

The problem of water level was addressed by building a weir upstream on the Irwell. Water was to be directed from the north side of the Irwell by driving a tunnel 800 yards long, eastwards through shale and sandstone across a bend in the river as far as Giant's Seat. Now, the colliery was on the opposite (south) side of the river, so Brindley's plan was to dig a tunnel under the river, connecting two shafts 73 yards apart, forming an inverted syphon. In order to allow the tunnel to be flushed when required, an adit was driven from the northern shaft to the river bank.

At the top of the southern shaft, in the hillside, an open leat or head race was cut, running south east along the bank of the Irwell. This leat (feeder canal) flowed 235 yards until just past the Wet Earth Colliery and then turned sharply west to enter the mine through a short tunnel. Entering the pumping chamber next to the pit head, the water drove a 23-foot (7 m) diameter overshot waterwheel that powered reciprocating pumps via rocking beams. The discharged water was directed through another tunnel into the Irwell.

Construction started in 1752 and the scheme was completed by 1756. It was so successful that the basic components remained in use for 170 years; the original waterwheel was replaced by a water turbine in 1867.

The above information is largely condensed from the Wikipedia entry, which is recommended for further reading about the colliery, which closed in 1968.

See also here for a description of the water system, with useful maps and diagrams.

A great deal of information is provided in the book Brindley at Wet Earth Colliery: an Engineering Study by A. G. Banks and R. B. Schofield, published in 1968 by David & Charles. This provides valuable information on the various features, namely the weir, main tunnel, ventilation shafts, washout tunnels, syphon, channel (leat) from syphon towards mine, feeder and tailrace to and from water wheel, Fletcher's Canal (which was a later construction), and the canal arm and colliery loading basin.

In 2020 'Martin Zero' produced a series of three YouTube videos relating the Wet Earth Colliery. These are well-researched and presented, and include film shot in the accessible tunnels.

See here for photographs of various tunnels and shafts, taken in 2020

The 1850 O.S. map here (surveyed 1844-6) shows the weir south west of Ringley Fold. The river meanders beyond here, heading in a general south/easterly direction. Brindley's tunnel starts on the north side of the river, just upstream of the weir. It is not shown on the map, but Banks & Schofield include a map showing the tunnel heading to a place on the northern river bank where the river bends to head due east for a short distance. What is shown on the 1850 map is the channel (leat) which ran from the inverted syphon towards the Wet Earth Colliery, keeping close to the river bank. On the 1850 map the channel heads about 800 ft westwards to a small group of buildings labelled Wet Earth. The channel also continues south-eastwards alongside the river as Fletcher's Canal, joining the Manchester, Bolton and Bury Canal (MBB&C) where it crosses the river by Clifton Aqueduct (the MB&B Canal having run alongside the river on the north side). However, the c.800 ft channel is not part of the original scheme. The Banks & Schofield map indicates that it was a branch constructed c.1790 to connect the colliery with Fetcher's canal. This map also shows the probable original course of the feeder (slightly further north on the channel) and of the tailrace (heading due east to the river bank).

Banks & Schofield refer to five shafts along the line of the tunnel, shown on the Deed plan. None are identified on the six-inch 1850 map. The first shaft was a short distance east (downstream of the weir) at a point where a short tunnel led from the main tunnel to the river, for washing out any silt. The last shaft was at the point where the tunnel turned to go under the river and where another short washout tunnel branched off, heading a short distance eastwards to drain into the MB&B Canal). The 1893 O.S. map here shows a ventilation shaft on the south side of the river, about 50 ft west of the start of the channel leading to the mine (now labelled as Fletcher's Canal). This shaft would have been at the south end of the syphon tunnel.

The 1954 map here and here show the ventilation shaft downstream of the weir, but not the one at the end of the syphon.

The main tunnel itself was larger than seems necessary for the required flow. It was partly lined with brickwork. Banks & Schofield estimated that over 6000 cu. yds. of spoil would have been excavated for the main tunnel, but they found no specific disposal sites.

The channel (leat) taking water from the syphon fell steadily towards the colliery at a slope of 1 in 200. It was cut through sandstone, or partly through sandstone and partly embanked with excavated material. Several overflows (spillways) were provided along the channel. Two of the overflows ran into brick-lined vertical chambers whose outflow was controlled by paddles.

As stated, the channel, which was to become Fletcher's Canal, continued eastward, but a short distance before the junction which would later be made with the MB&BC, Fletcher cut another channel off the canal to serve a water wheel for winding at Botany Bay Colliery.

The Wet Earth Colliery canal arm and loading basin were surveyed by Banks & Schofield in the 1960s. It was 900 ft long and 52 ft wide for the most part, narrowing to 26 ft near the tunnel entrance to the wheel chamber, where overflows were built into the stone wall of the basin. From here the water flowed through a short tunnel into a vertical masonry and brick shaft to connect with the a tunnel leading to the river. There was also a wooden sluice gate adjacent to the overflow, discharging into the same shaft. At the end of the basin was the wheel chamber tunnel.

By 1880, the seams had been almost worked out and the Fletchers sold the mines to the Pilkington family, who founded the Pilkington Tile Company. The Clifton and Kersley Coal Co was formed, and the shaft was deepened to work the Trencherbone seam at a depth of 607 feet. Further seams were worked including the Cannel, Victoria, Crumbouke and Five Quarters. In 1910, a tunnel was driven to connect to the Plodder Mine, which gave the mine a further lease of life until it flooded, resulting in it being abandoned.

The colliery was run down and closed in 1928.

To be continued.....

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