Thrislington Chronology
courtesy of John Smailes


1947
 Thrislington identified as a suitable source of high grade dolomite. Preliminary permission granted for quarrying
1949
 Steetley in partnership with United Steels test drill Thrislington, Quarrington and Beacon Hill (near Quarrington and Cassop) to determine quality and quantity of dolomite present. Coxhoe reserves were running out and hopefully a superior quality stone would be located.
Thrislington was identified as the best location to establish a new quarry/kilning operation to supply dolime to the expanding Steetley seawater magnesia works at Hartlepool
1954
 Steetley commence quarrying and build quarry processing plant. This included primary, secondary and tertiary crushers with associated washing plant and silos to supply a rotary kiln operation.
1956
 Work begins on T1, Thrislington's first rotary kiln with a dolime output capacity of 1800 tons per week. Made by FL Schmidt it was a modern version of the Steetley's first dolomite burning kiln built at Coxhoe in 1952. A rotary cooler replaces the planetary units used at Coxhoe. Kiln construction in line with Hartlepool production capacity increase when No5 Settler brought on line
1958
 Demand for dolime from Hartlepool exceeds the production capacity of T1. This necessitates the planning for installation of another rotary kiln.
1962
 T2 Rotary Kiln with a dolime output capacity of 2000 tons per week is brought into production alongside extra silos and quarry plant. Production capacity for Hartlepool is more than doubled.
The quarry operates with 4 Euclid dump trucks loaded by two Ruston Bucyrus loading shovels. One RB54 was electrically driven via a 3.3Kv cable, the other operated using a diesel engine,
1966
 A new Pegson Primary Crusher and associated plant is installed in preparation for anticipated tonnage increases. Thrislington would be required to supply not only Hartlepool but other markets such as steelworks and aggregates currently serviced from Coxhoe.
A ground limestone plant constructed to meet demands of current Coxhoe sales
1967
 Coxhoe Works closes but the rotary kiln continues to operate supplying dolime to Hartlepool.. Five Foden road wagons ferry dolomite from Thrislington to Coxhoe on a 16-hour 5/6 day a week schedule.
1968
 Quarrying operations are improved. Cat Loading shovels replace the old RB excavators. Hand held radios improve communications.
Roadstone aggregates business previously supplied from Coxhoe is transferred to the Thrislington operation. Quarry activities increase to a 2-shift operation to meet demand.
1972
 Rotary kilns fired using gas supplied to site from Hawthorn Coke Ovens via a 10 mile, 12 inch pipeline which cost £650k.
1974
 Electrostatic precipitators planned for T1 & T2 to meet environmental emission improvements.
1975
 Electrostatic precipitators operational on T1 & T2 at a cost of £500,000.
1976

Sinter Plant installed to supply large tonnages to British Steel as flux in the blast furnace operations.
Coxhoe rotary kiln refurbished at a cost of £191k to meet Hartlepool requirements. Consideration given to installing precipitators, but life expectancy of operation did not justify the expenditure.
Work begins on T3 design. To cost about £7 million and have a design throughput of 200,000 tonnes per year. British Steel requirements for Dolomet (to Redcar, Scotland, Wales and Scunthorpe) and Hartlepool for dolime exceed the capacity of both T1 and T2.

1977
 Fishburn Coke Ovens supply gas to Thrislington
1979
 T3 kiln with a dolime capacity of 5000 tonnes per week comes on-line and more than doubles burnt product capacity at Thrislington. All kilns now operated from a new central control room.
New rail fleet transports dolime to Hartlepool from the new rapid loading bunker built as part of the T3 extension
1980
 Coxhoe rotary kiln ceased production at the end of year once T3 operations established.
1982
 Thrislington quarry extension approved to secure  important supplies to both Hartlepool and British Steel.
1989 Village by-pass planned as part of the major expansion of quarrying operations. Steetley contributed £536k to the project.
Thrislington quarry extracts more than 2.5 million tonnes of stone. A record 1 million tonnes processed for civil engineering use.
1990 Summer months see the opening of village by-pass.
Operation Transplant completed. Thrislington Plantation completed after 8 years when 11 acres of grassland moved.
'Secondary liquid fuel' firing being tested pending potential authorisation by Environment Agency
1992 Authorisation granted to use 'secondary liquid fuel' as a firing supplement on the rotary kilns. up to 40% of total fuel input
Plans for a waste tip meet public and regulatory opposition
Redland acquires Steetley
1993 A 'secondary liquid fuel' tanker spillage at West Cornforth rekindles local concerns
1998 Lafarge SA acquire Redland
2004 After a management buy-out Steetley Dolomite Ltd formed from Thrislington and Whitwell operations