In 1887, the Walker brothers purchased their first quarry. Their father John had come to Canada from Scotland in 1840, and taught his sons the stone cutting trade. The stone was delivered via horses and carts, and down the Welland Canal. Through the years, aggregate from the quarries has been used in a wide variety of construction projects, including the QEW, Welland Canal, Highway 406 and numerous churches and government buildings.  

The company expanded and diversified through the years, acquiring other quarries and businesses. Locally, Walker owns Walker Brothers Quarries in Niagara Falls, Vineland Quarries in Lincoln, Ridgemount Quarries in Fort Erie and Spring Creek Aggregates in Beamsville.

Niagara Waste Systems, an environmental branch, turns worked-out areas of the Thorold quarry into a controlled landfill site. Once each landfill cell is filled, it is covered with a clay cap and seeded, to re-establish native vegetation.

The corporation invests back into the community, including donations to the Walker Family Cancer Centre in St. Catharines. It remains a family owned company, through five generations.