Plans to extend Guernsey's only active quarrying site at Les Vardes have been approved by the States of Guernsey.
There were concerns earlier in the year that if permission was not granted excavator Ronez may have to rely on imported stone.
The project is due to start in September and the extension should give the quarry another 18 years of life.
Peter De Garis, Ronez's general manager, said the extension was needed for them to continue their operations.
He said: "With the existing quarry coming to the end of its life, we had to make plans for where we were going in the future and it seemed there was an opportunity here to create an extension.
"Obviously with the infrastructure we have already set up with the processing, equipment and crushing in place it made sense to do an extension rather than look for a new site.
"We've got in the order of one and a half million tons of material in the existing site and the extension area will give us just over another million tons, so that will give us roughly two and a half million tons in total."