I’ve only ever heard the word dinted used in the Christmas carol “Good King Wenseslas”
In his masters step he trod
Where the snow lay dinted
Heat was in the very sod
Which the Saint had printed
The word dinted is also used in relation to coal mining.
Two methods of extraction were used in the Cumberland coal mines: room and pillar, and longwall.
Room and pillar
Room and pillar mining was used in Europe as early as the 13th century, with the method becoming known in North America by the early 1800s.”Rooms” of coal are excavated while “pillars” of untouched rock are left to support the roof of the workings. This method is used for relatively flat-lying deposits and has the advantage of reducing the risk of surface sinking compared to other underground mining techniques. Because significant amounts of ore (as much as 50%) are left behind, it is much less profitable than other extraction methods. Room and pillar mining lends itself to mechanisation but in the early days required significant manpower.
In rooms, if the surface was soft, the floor would be dinted downward two or three feet to gain height for the mine mules to pull full-sized coal cars. The rooms would also be driven wide. The dinting and the track would be in the centreline of the room and the extra rock stowed along the side ribs. In mines like No.5 with a working height in some seams of under 6 feet, if the floor wasn’t dinted, the mules would be forced to pick their way between the railway ties which were dug down to allow for this.
Ventilation was challenging. No.2 and No.3 mines in Cumberland had ventilation tunnels cut that connected to the workings. Fires made with waste coal near the entrances of the ventilation tunnels would draw the air and provide circulation, but because the mines were gassy this had its own dangers. At No.3, a furnace portal connecting several tunnels was created within the mine that moved air around – also dangerous and only slightly more effective. Every change in mine safety was written with the blood of the miners who had to die in large enough numbers to make it economically more advantageous for the owners to spend money and investigate safer methods to keep the workers alive underground.
No.1, No.2 and No.3 were the earliest mines opened in Cumberland. Later mines set up for room and pillar used electricity to power ventilation fans with intake and return systems.
While the technology has changed since this method was first developed in the 1700s, the basic idea remains the same. A tunnel road (called a main gate) is punched at a ninety-degree angle to one end of the coal seam face being worked. A second tunnel or gate (called the tailgate) is dug at the other end of the seam- creating a U shaped air circulation system. Intake fresh air travels up the main gate, across the longwall and out the tailgate.
The coal from the longwall face is undercut. Once the ore has been dropped, manual labour is used to bring the coal to the main gate tunnel where it is loaded onto coal cars. Wooden (later metal) props are placed to secure the roof of the working tunnel. Before more coal is cut out of the longwall, overlying rock is deliberately collapsed into the excavated space. This space is called the goaf, goff or gob.
In coal mines with thinner seams like those found on Vancouver Island, the gate roads were formed as the coal face advanced. The longwall being mined was as tall as the seam, but longwall gate roads were often dinted in the floor or ripped into the roof to make enough room to use full-sized coal carts.
The horseshoe shape of a longwall has been recreated in the replica coal mine in the lower level of the museum.
Joy loaders were first introduced in 1919 and mechanized the longwall method. After about 1936, conveyors were brought up from the recently closed No.1 (Esplanade) mine in Nanaimo and installed in longwall facelines, first at No.5 mine and then at No.8. Longwall became the preferred method of mining as it allowed near total extraction but could only be used when there were straight facelines. Any faults or curvature in the seam would halt the use of the longwall method at the face.
The joy loader outside the museum was used at No.5 mine, and there are some wonderful maps in the museum collection that illustrate what the underground workings look like using both room and pillar and longwall extraction methods.
In the Good King Wenceslas song, the dinted snow created by the saint warms the feet of the servant who follows behind him as they travel on their way to do good deeds, providing food for the poor. In the Cumberland coal mines, as far away from saintly intervention as can be imagined, the floors were dinted for economic reasons – to make the mules more effective pulling full sized coal carts. Extraction efficiency, not miner comfort.
It was already warm down in the mines, but it was also often gassy, wet and dangerous. The miners could have used a saint underground.
With thanks to Gwyneth Cathyl-Huhn for the information provided that gave me the idea for this post.