The company says it has written to all of its 125 staff and is hoping employees will offer themselves for voluntary redundancy.
A spokesman said: ‘The five posts are all in haulage, but the staff affected – if they choose not to be among the five who take voluntary redundancy – will be retrained to fill the posts of those who do.’ The reduction in the haulage operation is primarily intended to cut costs.
Ronez has already reduced its workforce through natural wastage and says the further cuts will ‘ensure job security in the longer term’.
Ronez Quarries in both Jersey and Guernsey used to be part of Aggregate Industries, which was last month acquired by global cement firm Holcim Group.
A spokesman said the job losses were not related to the takeover and that ‘nothing had changed’ in relation to Ronez’s management.