In the beginning it was not an exact science. As proof of that one has only to study the moorland hillsides of Dartmoor and it will soon become apparent that numerous trial pits had been dug. If they had been successful then a full blown mine would have opened up.
Prior to digging the "old men" searched for "shode", or stream tin, in the
riverbeds. Vast areas were dug over and river pebbles removed where they
contained large quantities of rich copper or tin ores. The traces of the
work of the ancient "streamers" on Dartmoor still show today. The wounds have
healed but the scars remain!
These sources of mineral were eventually worked out and the miners went underground.
Link to a map of the mine.
It was a real case of trial and error! Even so some mines sprung up which
were very successful for hundreds of years. They were the ones that had
hit upon the rich veins which lay beneath the surface.
Wheal Friendship at Mary Tavy was one such mine. At one stage it was the most productive copper mine in the world. Later, at very deep levels, tin was discovered, but unfortunately at a time when tin had also been discovered overseas in easily accessable alluvial deposits.
There was not enough profit to enable the lower tin levels to be worked and it was abandoned.
During its heyday Wheal Friendship employed over 1000 men. The village
population of Mary Tavy expanded rapidly and with it came all the social problems
that one associates with such a rapid influx of people. Disease, poverty,
drunkeness and immorality was rife - just as it was elsewhere in the area
where minerals had been discovered.
Mary Tavy was not particularly prone, nor exempt, from these problems more than anywhere else.
Access in and out of the mine until quite late in the life of the mine was
by ladder! These were set inside the shaft and were about 20ft in length.
The bottom of the ladder would rest on a platform built or "trigged" across the shaft. Within this platform was a trapdoor which led to a similar ladder going down to lower levels and another platform. So the system progressed, each platform being set below the next as the shaft was sunk deeper.
NB. The platform cross-support timbers were often wedged into position!
Cornish "man engines" operated in some mines in Cornwall. It consisted
of small platforms attached to a long rod, hundreds of feet long in some
cases, which was connected to a beam engine at surface.
The stroke was the distance between the wooden platforms (See picture).
5> By stepping on and off the plates one would then be raised easily from one platform to the one next above (or below - depending whether one was going up or down). Only the large and prosperous mines had such engines. The man-engines have been known to break with disasterous consequences!
The "tut" workers almost always set off at right angles to the shaft and cut
galleries into the tunnel sides hoping to strike the mineral veins.
The decision as to where to dig was decided by the "Underground Captain" who was a very experience mineralogist and ex-miner himself. He knew from experience and previous records what to expect - if he was lucky! It was still all trial and error working!
When a mineral vein was discovered then the "tribute" miners could get to work. Because they were only paid according to the VALUE of the ore raised they would never remove any more material than was necessary. They would follow the vein or "lode", sometimes only removing just enough so that they had room to work in - especially if the lode was narrow. The technique was usually "overhand" working - ie. they dug upwards as opposed to downwards. This made it easier to remove the ore as it fell under its own weight. "Underhand" working would mean that they had to lift it as opposed to dropping it!
The miners would reach as far above their heads as they could and then installed a rickety platform, wedging it in the crevice that they were excavating. The good ore they tossed over the edge to fall down to the bottom of the crevice or "stope". The waste was piled under their feet on the platform, raising themselves always upwards as they worked. When the platform was creaking under the weight of the waste they would install another platform above the proceeding one and repeated the performance all over again. This was know as "stope working" and was a precarious business. Some stopes could rise to 50ft - 80ft high!
Just imagine being perched on a tiny rickety platform, swinging a pick or hammer and with only the stub of a candle for light! Accidents were frequent and the air foul due to the inability to pump fresh air into the mine. Compressors were a modern innovation and not available to most of the working life of Wheal Friendship. After all it had started in 1740 - the date of earliest records for the mine.