Each of the Channel Islands has its own distinctive history. Quarrying in Jersey, Guernsey, Alderney, and Herm resulted in the emergence of Ronez Limited, as the principal quarrying company in the Channel Islands.


The origins of Ronez Limited lie in the history of Jersey where there may be evidence of commercial quarrying as far back as 1651. There is reference to Clos de Carieres in the parish of St John where almost two centuries later the Ronez quarry was established when the Jersey Granite Company commenced operations there in 1869. A successor to this company was acquired in 1911 by the Croft Granite, Brick, and Concrete Company of Leicestershire.

In Guernsey there was originally a quarry at St Germain at the Castel in 1639. In 1840 John Mowlem, founder of the famous civil engineering firm, renewed the paving of Blackfriars Bridge with setts of Guernsey granite. The repaving of London Bridge and the Strand followed, and the granite for the Thames Embankment, 1862-74, also came from Guernsey. By the end of the 19th century Mowlem's Guernsey operation had a steam crusher, and all the paraphernalia of weighbridges, storage yards, workshops, stables, blondins and offices. In addition to the quarries owned, Ronez also had some they leased.

19th century

In the 19th century the ports of St Helier in Jersey and St Sampson in Guernsey were important for the export of paving stones and chippings to the English mainland. However, by the early 1900s St. John's quarries had acquired their own jetty, crane, mooring buoy and were on occasion loading three ships or more at a time with aggregate.

19th Century Channel Island census returns speak of quarrymen, stone cutters, stone dressers, stone crackers, and stone miners, as well as stone merchants, and as the demand for stone grew, so labour had to be imported. Normandy and Brittany were obvious sources, but so too were England and Ireland, and even Scotland. In 1886 the Stone Crackers' Union was formed to defend the interests of quarriers and in 1911 it was superseded in Guernsey by a branch of the United Union of Quarrymen and Settmakers. In 1937 it was incorporated into the General and Municipal Workers Union which was active throughout the Channel Islands.

1940's and 50's

The German occupation of the Channel Islands from 1940-45 saw the requisition of the islands' quarries. The quarry manager at St. John, as a result of being a British citizenship, was interned by the Germans in Bavaria for the duration of the war. In Guernsey, Mowlem's plant was brought back into use by the Germans. The quarries on both islands were worked by slaves brought over from mainland Europe by the Germans who built railways on both Jersey and Guernsey to deliver the crushed stone and cement needed for building Hitler's Atlantic Wall.

With the war over the quarrying on both islands had to undergo a long and expensive process of reconstruction and several quarries did not reopen as their rehabilitation was deemed uneconomic. At St John, engineers came over from Croft to rebuild the plant and to build a new jetty. This gave opportunities for rationalization and technical advancement. Horses and carts and steam cranes gave way to huge excavators, dumper trucks and loading shovels. Furthermore, electricity took over from steam.


In March 1961 the Jersey Cement and Granite Co. Ltd., commenced operations in Guernsey, thereby linking what was the separate quarrying traditions of the two islands. This was done by the acquisition of the quarries at Les Vardes, Bordeaux and Mont Cuet.

In the following year, 1963, ownership of the Jersey Cement and Granite Co Ltd was transferred from the Croft Granite, Brick, and Concrete Company, to English China Clays Limited and in 1966 in Jersey, Western and L'Etacq quarries were purchased. At the same time, the Company extended its interests to Alderney, leasing land there at the Arsenal. A year later it changed its name to Ronez Ltd.

Modern times

In 1996 Ronez Ltd was acquired by CAMAS which in turn merged with Bardon Aggregates to become Aggregate Industries Ltd. In March 2005, Aggregate Industries merged with the Holcim Group, an enterprise of Swiss origin which since it began in 1912 has achieved global status.

The story comes to an end for the present; when on the 5th January 2017, Ronez Limited in the Channel Islands was acquired from Aggregate Industries by SigmaRoc Plc.