Covia Mine

Further prospecting in 1910 outlined a large deposit of ore located a few kilometers north of the lake. Two geologists studied the grey basic rock, and identified it as Nepheline, an inert igneous rock that is made up of three types of minerals: microcline feldspar, albite, and nepheline.

 

At that time there was no known use for Nepheline. However, in the late 20s and early 30s the glass industry discovered that additions of alumina to container glass compositions controlled devitrification and gave the glass increased resistance to chemical attack.

 

Devitrification in glass occurs during the firing process, with the surface developing a whitish scum or wrinkles instead of a smooth glossy shine. This is caused by the molecules in the glass changing their structure into crystalline solids.

 

Feldspar was first utilized as a source of alumina, however Nepheline, which contains a higher alumina content than feldspar on its own, was an obvious alternative. 

 

Mr. W. Morrison, a prospector, bought a few hundred acres of the Nepheline Syenite deposit in 1934 from Mr. Fred Walsh of Douro. A sample of pit run material was sent to Dominion glass in Hamilton. Those tests were encouraging, and a potential customer was found. 

 

A year later Mr. Morrison sold his claim to Mr. Harold Deeth. Deeth obtained financing and in 1935 formed Canadian Nepheline Limited and built a small mill in Lakefield. The mill consisted of a single jaw crusher, two sets of Woodstock rolls which were intended for grinding grain, one Niagara Screen, and a Dings magnetic separator. The broken ore was hauled by truck to Lakefield for processing into glass-grade sand. Their initial order came from Dominion glass and was for 40 tons.   

 

In 1936, the first mill was built at the Nephton site. The crusher, conveyors, and screen were driven by a single-cylinder diesel engine, and the ore was crushed to four inches and finer. To feed the mill, dumpsters and buckets were used. Two men sledged rocks and loaded each bucket while the ore was sorted on a picking belt. Many of the men came from a distance so a combined cookhouse and bunkhouse were built halfway up the hill. 

 

In 1937, Canadian Nepheline Limited, wishing to expand, obtained financing from Ventures Limited and formed a U.S. subsidiary, American Nepheline Limited, and built a 100-ton per day mill in Rochester, N.Y. Ore was trucked from Nephton to nearby Stoney Lake where it was loaded onto barges. The barges hauled the ore to Lakefield, where it was then transported via railcar and taken to Cobourg, Ontario. From Cobourg, the ore crossed Lake Ontario by railcar-ferry to be processed into sand and fine grind products at the Rochester plant. 

 

In 1946, Canadian Nepheline Limited was restructured and was renamed American Nepheline Limited. A new mill was constructed at Nephton and by early 1947 this 400-ton per day plant was in production. This sand was trucked to Lakefield where storage silos were set up at the former Canada Cement plant and two pebble mills were installed to produce fine grind products.

 

A town site also was constructed that housed employees and their families. Through the years the townsite progressed from eight houses built in 1950 to a peak of 22 houses before the townsite was dismantled in the late 1980s. A number of these houses were relocated and are now located in the Havelock and surrounding area. 

 

Also on site were other amenities. The original recreation building for the employees was converted to a school, and then to a library when school busing began. The townsite also had a curling rink with two sheets of ice, tennis courts, and an outdoor rink in the winter. A small restaurant was known for providing home-cooked meals and delicious baked goods while a company beach on Stoney Lake provided swimming opportunities in the summer.

 

In 1954, additional shipping capability was added when the Canadian Pacific Railway built a new 27-kilometer branch line that extended from the main line in Havelock to the mine site. The official opening of the line was attended by Leslie Frost, Premier of Ontario, and Mr. N.R Crump, CPR President. 

 

Through the years as sales increased and additional equipment was added to the old plant restricting space, the decision was made to build a new 600-ton per day mill. Incorporating the best available equipment and technology, the mill was built to provide room for whatever future expansions would be required. In July 1956 this new plant became operational. 

 

Over the years, steady increases in capacity have been made and the original 600 ton per day rate has grown to three times the amount. 2022 marks the 87th year of production at the Nephton site. The Nephton plant was slated to close in 2022 and move all its operations east to the Blue Mountain plant, but this move is now under review and delayed.  

 

This backgrounder was shared by Michael Levesque, COVIA’s Plant Technical Training Coordinator. For more information about COVIA, you can visit http://www.coviacorp.com