Gregorys chalk mine, Plumstead

During the late 19th century in the neighbourhood of Kings Highway, Wickham Lane and Alliance Road in Plumstead lay three brickfields: Gregorys, Cemetery and the South Metropolitan. Each had its own substantial chalk mine, with many of the galleries being poorly constructed and highly dangerous to both those working underground and living/working above ground. A fourth mine, Dawsons, is reputed to exist slightly to the south of Gregorys, but has never been surveyed. The photo below shows Gregorys - skillfully worked passageway with a narrow profile; if all the mines had been this good, subsidence would not have been a problem at Plumstead.


The plan below of Gregorys (Alfred Gregory & Co) has never been published before; remember that it is/was surrounded by other huge mine workings whose galleries are not shown (although under 16-18 Villacourt Road an extremity of the South Metropolitan mine is plotted).

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After severe surface subsidence above the Cemetery and South Metropolitan mines, the "London County Council (Woolwich Subsidences) Act 1950" came into existence, which financed and managed the filling of all three mines. All the known galleries have now been filled, including Gregorys mine, which ironically was excellently worked with a probable further lifespan of 200-300 years. Many voids almost certainly still remain; time will tell if the associated air pockets continue to work their way up to the surface. The fact that money was wasted filling Gregorys demonstrates a complete lack of knowledge about chalk mining and a process driven by politics and public opinion rather than expert opinion.

The picture below shows the Wickham Lane brickfields about 1900 (look closely about 60 feet to the left of the base of the chimney, and you will see what appears to be a circular ground collapse crater):

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A 1958 article in London Transport Magazine discusses the South Metropolitan mine, part of which was located under the bus garage which formerly stood at the junction of Kings Highway and Wickham Lane:

Down the ladders of a dank shaft and into the eerie workings of a disused chalk mine went our somewhat apprehensive reporter. Dim electric light bulbs and the narrow beam of a hand lamp showed the way into a darkened gallery. It was an unusual expedition. Sixty feet above was Plumstead garage, with the buses coming and going as usual. Though new to our reporter, this inspection was a routine affair for the three men in his company. He was there to see an out-of-the-ordinary job which our civil engineers have been tackling for the past year. They are trying to trace and fill in a maze of chalk tunnels beneath the garage.

Before the days of lorries chalk for building was actually mined like coal, instead of quarried. But at the turn of the century easier transport made mining uneconomic at Plumstead, and the workings were abandoned. There have been serious subsidences in the vicinity over a long period, and five years ago London County Council, realising the danger of the mines, began finding and filling in the cavities. Last year their excavators discovered galleries leading under Plumstead garage and our engineers were called in.

Bore holes have been made in various places to test the solidity of the ground and several shafts have been found in and around the garage. Sixty feet below ground a heading, about 250 feet long, has been bored and this gives access to two old galleries. One cavern our men stumbled upon was large enough to take a bus! Several of the cavities have now been filled in. A mixture of pulverised fuel dust and water is pumped down and this eventually sets like cement.

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Both items above from the Kentish Independent about 1950.

The Co-op chalk mine, Abbey Wood

In 1900 the Royal Arsenal Co-operative Society dug a substantial chalk mine in Federation Road, Abbey Wood, to supply lime and chalk for its new "affordable housing" development nearby.

As often happens on this blog, we give you material that has never been published before; the high-quality plan below shows the mine along with proposed works to convert it into an air-raid shelter:

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A publication by the society gives details of the works:

A shaft has been sunk from which chalk is being obtained for use as a foundation of the roads. From the shaft also a plentiful supply of water is obtained, which is used for the mixing of mortar and other manufacturing purposes.

A copy of RACS magazine noted that the hoist of the chalk pit was worked by a 16 horsepower engine which also drove other workshop equipment. It also mentions a mortar mill and lime kiln associated with the mine, and goes on to describe the mine in more detail:

The chalk pit descends 60ft perpendicularly, from that level four galleries extend horizontally about 100ft each, and from these the chalk is being continually raised. The water that percolates into the pit is pumped up and distributed where needed. Some of the chalk is... carted off on the tramlines for making the roads, but most of it is first burned in the lime kiln, then slaked, then mixed wth the fine sand, which by the way, overlies the chalk, to make the plaster for internal walls.

The mine was only active for about five years, which demonstrates the considerable length of passageway that can be created in a short span of time. It was thoroughly examined by Per von Scheibner in the late 1980s, which included extensive new photographic coverage.

The galleries were skillfully worked and shaped, with generous pillars left to support the land above. With regular inspections, this mine may well have a further 200+ years of life before complete filling becomes necessary, although localised repairs may be required periodically.