Blasting is scheduled to take place Tuesday at the Swenson Granite quarry in Concord as the Canadian firm that owns the company continues preparations for what could be a resumption of granite-cutting operations.

“Multiple blasts” will occur between noon and 3 p.m., according to a notice sent by Polycor to City Hall. This would be the first blasting at the quarry since late February. The blasts are part of processing already-cut stone into smaller pieces known as aggregate, which is sold for a variety of uses.

Swenson Granite stopped cutting new granite last summer in the main quarry, known as the “deep hole” because it reaches 300 feet below the surface. It was the last major granite quarry operating in the Granite State.

Polycor, the Quebec firm that manages Swenson Granite, said the stoppage was made for “changes to the quarry footprint and are ultimately designed to bring the cost of quarrying dimension stone at Concord to sustainable levels.” They said full quarrying was planned to resume in the summer of 2025.

Swenson Granite’s retail operations have not been affected.

Granite has been cut on Concord’s Rattlesnake Hill since before the Civil War. Swenson Granite was formed at the turn of the century when John Swenson, who came to the U.S. from his native Sweden, consolidated some 40 small quarries to form the company in the 1880s.

After four generations of family ownership, Swenson Granite was sold to TorQuest Partners in 2016, which bought Quebec-based Polycor to manage this and other quarrying sites, including Rock of Ages in Vermont. Birch Hill Equity Partners of Toronto now owns Polycor and its businesses.