Pugwash limestone

A limestone quarry near Pugwash provided “road metal” in the 1930s. What is road metal?!

There was an historical limestone quarry at Dewar’s Hill, across Pugwash Basin, southwest from Pugwash, Cumberland County. The quarry was first operated sometime prior to 1914 when a government report said it was no longer active at that time.

According to the report, the limestone had been shipped to Prince Edward Island for use as agricultural lime, which is spread on farm fields to improve soil quality. Lime is produced by crushing limestone down to powder and calcining it. (Calcining means heating a mineral to the point of changing its mineral structure. It is done as part of the process of manufacturing minerals into products. Calcining limestone removes carbon dioxide and leaves behind lime.) Much of Nova Scotia’s limestone production has been to produce lime for farmers.

We could not grow enough food to feed earth’s population without fertilizers and other tools made by possible by mining.

The Dewar’s Hill quarry was idle until 1931 when it was reopened and operated jointly by the Nova Scotia departments of Agriculture and Highways to produce both agricultural lime and crushed stone for surfacing highways.

A memo written that year by the provincial government’s “Limestone Committee” said Nova Scotia used about 3,000 tons of limestone per year but that much more should be used in agriculture. The memo suggested Nova Scotia should use a minimum of 16,000 tons of limestone per year and that the Department of Agriculture should “bring the advantages of the use of limestone to the attention of farmers….”

The Limestone Committee believed that “a policy which depends on using portable, inefficient and intermittently operated plants can not attain the objects in view. It is essential that at least one modern properly designed plant be constructed and operated at or near its rated capacity.” This led to the reopening of the Pugwash quarry and a plant to manufacture lime.

A 1934 federal government report refers to the site also producing “road metal,” a British term for crushed stone used to build roads. In this case “metal” refers to the Latin word “metallum,” which means mine/quarry, so road metal means rock that came from a quarry. “Metalling” a road means to apply gravel to it.

The term road metal is not generally used in North America today, so the 1934 report’s use of it hints at Canada’s early British influence.

The quarry was long and narrow because it followed a band of limestone – it was a cut, not a hole. The old, pre-1914 workings extended for 500 yards and had a width of 15 -30 feet and a depth of 10-20 feet. Soil had fallen into the old quarry and hidden most of the rock by the 1930s.

When reopened in the 1930s, excavation was done by steam shovel and the quarry had a working face 35 feet high. Jackhammers driven by a portable air compressor drilled holes into the limestone into which dynamite was inserted to blast the stone and break it free from the working face.

The broken stone was loaded into side-dump cars and taken by gas-powered locomotive over a narrow-gauge tramway through the cut to the crushing and pulverizing plant, which was located at the nearby shale pit formerly worked by Nova Scotia Clay Works Ltd. Nova Scotia Clay Works opened in 1889 and grew to produce one million bricks per month before closing in 1931. Its shale pit was near the shore of Pugwash Basin, about 200 yards from the Dewar’s Hill quarry.

The quarry’s mill had two storage bins, each with a capacity of 250 tons, well short of the total 6,000 tons of storage the Limestone Committee recommended. Bins were necessary to keep the crushed limestone and lime dry.

Shipments were made over a standard-gauge railway spur, which previously served the shale pit, to Pugwash.

A 1942 memo written after an inspection by the Department of Mines said the quarry was being worked by a Mr. Woodlock for the Department of Agriculture, so it remained active until at least then. In 1961, a test was done on the quarry’s limestone by the Nova Scotia Technical College, but it is not clear whether the quarry was active at that time or if reopening it was again being considered. It is common for quarries to be worked intermittently which can make it difficult to determine when a quarry permanently closes – unless a deposit is depleted or extraction of it is somehow prevented, there is always the possibility a site might be worked again.