Merehead Quarry was established by the Leigh-on-Mendip Quarry Company in the early 1930s. The quarry was in production by 1934, in which year it employed 29 men and covered an area of 30 acres. In 1935 the company went into liquidation, and by 1937 the quarry was being worked by a new business, the Merehead Quarry Company.
In 1938 Limmer & Trinidad took over the quarry with the benefit of a 42-year lease. By 1941 the number of employees was only 25, and the quarry was still using horses to haul the tubs along a narrow-gauge rail system. Merehead was also proving to be a difficult quarry to work, the narrow valley in which it was situated providing a limited area for manoeuvre, while waste and overburden was running at more than 20% of output. Limmer & Trinidad set about expanding production and after the war invested £34,000 in a rail link south of Leighton and a plant which included a facility to produce powdered limestone for the manufacture of mastic asphalt. Unfortunately, the stone produced by the quarry was found to be unsuitable for use in the grinding plant, presenting the company with the need to find an alternative local source. Following a favourable report on Dulcote Quarry from a geological chemist in 1956, it entered into a five-year contract with Foster Yeoman Ltd to supply the plant.
In 1959 Foster Yeoman bought Merehead Quarry and around 150 acres of land for £15,000, the price including the quarry plant and machinery. The quarry was mothballed for nearly three years, but in 1962 a major redevelopment programme commenced. Foundations for new plant were laid in that year and in 1963 a Kue Ken primary crusher was installed.
After much discussion it was decided that the new quarry would be run by a separate company which was to be called Foster Yeoman (Merehead) Ltd. By February 1964 the secondary crusher was in position, the bunkers nearly completed, and the screens were arriving. A new coating plant was bought from Stothert & Pitt, and to save money much of the work of erecting it was carried out by Foster Yeoman staff. The quarry was in production by the autumn of 1964, and in 1965 was the subject of an article in the “Quarry Managers Journal”.
The new plant at Merehead was fully integrated. Stone was brought from the quarry by dump trucks and tipped into a receiving hopper and shute from where it was directed into the apron feeder of the Kue Ken primary crusher. The primary reduced the stone to an eight-inch product which was carried by conveyor into an adjacent secondary crushing and screening building, where it was first scalped to remove any material less than 1½ inch, these scalpings being carried by conveyor to a Blaw Knox hopper for disposal as a rough-size product. The oversize material then passed through the secondary crusher, which was set to produce a three-inch product. This was then conveyed to the tertiary crushers for further reduction before passing to the screening house for final grading and storage. A proportion of this screened stone was also carried by conveyor to the nearby Stothert & Pitt coating plant for tarmacadam.
In 1967 the decision was taken to redevelop Merehead around a giant Nordberg gyratory crusher with a capacity of 2,000 tons per hour. Work began in March 1968 on blasting the foundations for the Nordberg and by July the pouring of concrete had begun. To distribute the increased output of the quarry Foster Yeoman laid a railway branch into the quarry in the winter of 1969. In March 1970 the Nordberg crusher was commissioned, and in June the new rail branch opened for traffic.
The Merehead branch was officially opened on 19th August 1970 as the Merehead Stone Terminal in a double ceremony that also marked the completion of the new plant and the re-naming of the quarry as “Torr Works” after the quarry’s engineer, Ron Torr . The first ceremony of the day was the opening of the rail link, which was to be done by the chairman of the British Railways Board, Sir Henry Johnson. The second was the official opening of the plant by Angela Yeoman.
A tripper overhead loading conveyor at Torr Works was later ercted at the rail sidings in the quarry to speed up and reduce the cost of loading trains. The conveyor belt was mounted on a line of concrete columns and ran the length of the sidings, the trucks being loaded by a chute that moved backwards and forwards along the belt. In March 1971 the 1,000th train left the quarry, and in June the company celebrated the despatch of the millionth ton by rail. In 1973 a new railway line was built to allow incoming trains to run directly into the quarry and provide arrival sidings. The new line, known as the chord, opened in September, increasing the line capacity to the planned 30 trains.
Output at Merehead had increased dramatically, passing the 2m ton mark in the financial year 1969/70. This greatly improved output demanded changes in the quarry face operations. Overburden was removed by a Caterpillar tractor and scraper combination, and the company now possessed five drilling rigs, of which four were in use at any one time. These machines drilled 5-inch diameter holes, which were then charged with slurry explosive, an average blast bringing down 20,000 tons of rock. The blasted rock was then loaded into Caterpillar dump trucks at the face using Cat 988 tractor shovels and taken to the Nordberg. Having been processed through this primary crusher, the stone passed to a scalping screen and on to a pair of large covered stock bins with a total capacity of 6,000 tons. Conveyors in the base of these bins fed a pair of secondary crushers (Brown Lennox Pennsylvania impactor mills) and the output of screened and oversized material was directed into tertiary crushers (2 GEC reversible impactors and a Symons short head cone crusher).
In the early 1980s Foster Yeoman was looking to re-equip Torr Works to increase both its output and efficiency. The Nordberg crusher was now more than ten years old and larger machines with significantly greater output were available. Moreover, as the lateral spread of the quarry increased and the working faces retreated further away from the crusher, the movement of rock between the two became increasingly expensive, even using the company’s new giant Caterpillar dump trucks. One possible solution was to re-site the primary crushing plant further into the quarry; but another and more radical one was to install a walking primary crushing plant which could be moved to whichever part of the quarry was being worked at any given time.
The company decided on a walking crusher and ordered a machine from Orenstein and Koppel (O&K). Weighing in at 1,050 tonnes and the height of a seven storey building, the mammoth crusher was designed to be moved by “walking” cylinders to any part of the quarry floor. At the heart of the structure was a Fuller Traylor 54-inch primary crusher, designed to reduce freshly blasted rock to 9-inch pieces. Power for the crusher was provided by a 400kW motor driven by the quarry’s 11,000 volt power supply delivered by a trailing cable. The crusher was designed to be capable of producing an average daily output of 22,500 tonnes in a single shift. It was delivered to Torr Works in October 1983 and commissioning began in August 1984. In November trials of the mobile conveyor sections were made and after a further three months of testing and modifications the plant entered daily use in February 1985. The stone from the walking crusher was carried along an extensive system of moveable conveyors to a large covered stockpile, from where it passed to a new secondary plant with a higher capacity than that built commissioned in 1970.
In 2006 Foster Yeoman was taken over by Aggregate Industries which continues to run Merehead Quarry.
NGR: 369600 - 144200
Lat : 51.1962027067
Long : -2.4364428043
- Black Rock Limestone
- Vallis Limestone
- Clifton Down Limestone
- Oxwich Head