Coal goes better with coke

Posted on February 23, 2021 • See the rest of our news

The mine workings in Cumberland (originally Union) are first developed in the 1860s and 1870s by the Union Colliery Company, but the original group of investors run out of capital and sell their rights to the Dunsmuir Family. In 1888 James Dunsmuir brings in, experienced coal miners and Chinese labourers to work the claim. A rail line to Union Bay is constructed and the first shipment of Cumberland coal goes to market by early summer 1889. 

There are four types of marketable coal: anthracite, bituminous, sub-bituminous and lignite. The coal in the Cumberland area is bituminous or “soft” coal, most commonly used today for electric power generation but in the late 1880s, it is mined primarily for its high heating value. 

No. 4 mine is typical of the Cumberland mines, with narrow deposits and coal seams anywhere from 18 inches to 3 feet in thickness, separated by bands of waste rock that has to be undercut and removed so that only the coal is harvested.  The coal quality is good, but miners spend a lot of time bent over or on their knees in cramped, low-ceilinged stalls with the hiss of escaping gas, dripping water and rats for company. Each miner has their filled coal carts tagged and tallied and are paid less than 60 cents per ton for their efforts. Any more than 65 pounds of waste rock in a ton of coal and the miner isn’t paid for the load. Once tallied the coal is loaded and shipped by rail down to Union Bay.

The larger chucks of coal – lump, pea and nut- are sized, sorted, washed and stored for export beside the docks. The coal is then loaded on ships primarily bound for the U.S. market. The slack coal, sized as rice or barley or fines, which is less than 3/4 inch in size, is not economical to ship in bulk, but it is the perfect size to coke. Coked coal brings a significantly higher price at market as it is used in steel production. It takes approximately 6.5 tons of slack coal to make 4 tons of coke but coked coal is worth $15.00 to $20.00/ton, versus $3.75/ton for bituminous coal

The first coke ovens are built-in Whyte’s Bay at Comox Lake, adjacent to No.4 mine, in 1892.

It is clay from No.4 mine that makes the bricks for the first trial coke oven at Comox Lake. In early 1891 clay is sent to Victoria and 2000 fire bricks are manufactured by Elford and Smith. The bricks are a very good quality and can be produced cheaply. Unfortunately, there isn’t a large enough deposit of clay to manufacture the quantity of bricks that will be required when coking goes into full production at Union Bay. 

According to the 1892 BC Ministry of Mines Report, 100 sacks of coke are sent to the Albion Iron Works in Victoria to be tested in the smelter there. The first shipment of coke to San Francisco is in early June 1892. Just after this shipment, No. 4 mine is closed down due to a worldwide depression, reopening in November of the same year. In January 1893, ten more coke ovens are constructed at Whyte’s Bay. By the end of 1893, 250 tons of coked coal from No. 4 mine have been sold.

In 1895 trained bricklayers along with a boatload of fire bricks are brought in from Scotland to build 100 coke ovens at Union Bay. The ovens have to be torn down and rebuilt in 1897 after an unsuccessful trial. Each coke oven is 12′ in diameter, meant to burn 6.5 tons of coal for sixty to seventy hours. Slack coal and any coal dust left after sorting is shovelled by Japanese workers into beehive-shaped coke ovens insulated with a layer of dirt and then ignited. After the doors are sealed with brick and mud, the coal is left burning under low-oxygen conditions for two or three days, reaching temperatures of nearly 2000 degrees C (or 3600 degrees F). The impurities- organics such as sulfur, minerals, ash, hydrocarbons and moisture- are burned off and are vented through a hole in the roof of the oven. 

The coke ovens were constructed of angled brick and on the top of each oven was a charging hole with a big metal lid on it. They kept them at a very high temperature all the time, twenty-four hours a day. When they pulled the coke out they used big long rakes.” *

There were fifty coke ovens back to back in a row, and the same on the second row, 681 feet long with one hundred foot high smokestacks. When it burnt, before they put charging holes on the ovens, there were huge flames; it was just beautiful at night.” **

What remains is coke, which is almost pure carbon, and slag, which is discarded as waste. The ovens are always kept at a minimum temperature of 600F the ovens operating around the clock. 

At the end of the process, the coke is raked onto the cooling sheds on either side of each oven. Coke is gray, hard and porous as opposed to the slag which is gritty -coarse black or gray rocks- sometimes glassily coating the interior of the coke ovens. While slag was discarded in early coking, today it is used as an ingredient in brick-making, mixed cement, shingles and fertilizer.

Union Bay is a thriving international community while the coke ovens are operational. East Indians build the docks and modify the wharf in 1892 for the gentle handling of the coke, Japanese stoke the coke ovens and Chinese men who originally came to build the railway work twelve-hour shifts as trimmers on the coal ships. There is a locomotive repair shop, foundry, boilermakers and blacksmiths all there to support the mining operations.

Smelters start building their own coking ovens and the demand for coke gradually decreases. The last sale of Cumberland coke is to the Trail smelter in 1922. The beehives are left as an interesting feature on the landscape until the late 1950s when the coke ovens are dismantled and the bricks are sold off. Cleaning the bricks to re-use takes time and effort.

A number of houses in the Comox Valley are faced with these bricks, some still stamped with  John C Stein Brickwork’s Bonneybridge, Scotland. There is little evidence left in Union Bay of the coke ovens but there are photos. Nothing is left of the original trial ovens at Whyte’s Bay.

The coal hills at No.1 Town in Coal Creek Historic Park and No.5 mine adjacent to Kendal Avenue are made up of slack coal, not slag, as coking was only done near No.4 mine and in Union Bay.

If you walk by the BC Liquor Store in Cumberland, you’ll see the unique angled bricks that were once part of the beehive coke ovens in Union Bay. The exterior walls at the front of the building are a visual homage to the coal mining history of Cumberland.

*    Mosaic of Union Bay, Janette (Glover) Geidt, 2006

**  Mosaic of Union Bay, Janette (Glover) Geidt, 2006

With thanks to William David Whyte and Karl Cameron for a very interesting thread posted on Facebook in “Old Cumberland” that inspired this blog post.