Summary

Mine Type	Underground
Status	Active
Commodities	Salt (rock)
Mining Method	Continuous Room-and-pillar
Production Start	...
Mine Life	...
Snapshot	The Winsford Rock Salt Mine is the U.K.’s largest and oldest working mine and Britain’s leading supplier of natural rock salt, used by maintenance professionals to deice roads in winter. It was the first Compass Minerals facility to adopt continuous mining technology, replacing the traditional drill-and-blast method for salt extraction. The mine is operated with modern mining equipment and utilizes subsurface improvements, such as vertical shaft lift systems, milling and crushing facilities, maintenance and repair shops, and extensive raw materials handling systems.

Deposit type

• Sedimentary

Summary:

The final rock formation at Winsford has four distinct rock salt seams or ‘halite’ as it is known (halite is taken from the Greek word ‘hals’, meaning salt). Each rock salt seam averages 25 metres (80ft) in thickness.

The remaining strata consist of rock salt with Keuper Marl bands and Keuper Marl. The youngest of the Triassic rocks in the series, Keuper Marl is usually amber or brown in colour, although on occasions it can be blue or green. Due to many of the influencing geological aspects, the colour of Winsford’s salt varies greatly – it can range from clear to pink through to dark brown, although a mixture of dark brown and pink is most commonly found.

The beds of salt worked at Winsford are relatively flat. There are two economically workable beds of salt known locally as Zone ‘B’ and Zone’F’. These beds lie between 130 and 220 metres below the surface. As discussed earlier the bed is, on average, 25 metres thick but the purest salt is located in the lower part of the bed.

Winsford rock salt is more than 90% pure sodium chloride, with the remaining insolubles consisting mainly of Keuper Marl, which is a layer of clay from the late Triassic or ‘Keuper’ period.

Keuper Marl has weathering properties, which give Winsford rock salt its unique ‘thatching’ effect, protecting the salt quality.

Marl also contributes to improved friction when salt is used as a highway deicer.

Mining Methods

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Comminution

Crushers and Mills

Processing

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Commodity Production

Operational metrics

Metrics	2024	2023	2022	2021	2020	2019	2018	2017	2016
Annual production capacity	....	....	....	....	....	1,500,000 tons of salt (rock) de-icing salt	1,500,000 tons of salt (rock) de-icing salt	1,500,000 tons of salt (rock) de-icing salt	1,500,000 tons of salt (rock) de-icing salt

Personnel

Job Title	Name	Profile	Ref. Date
.......................	.......................		Mar 3, 2025
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