Gold/Silver/Copper/Diamond/etc. mines, but also Coal mines, and of course Ghost Rock mines, will probably be a common feature of DL:R campaigns. At least, several adventure ideas presented in this thread involve them. As such, this post is going to gather information on mines (copypaste from the Internet), that could be of use in the game. I will probably update this post as I find more info on the subject.
Using Mines in DL:R for Dungeon Crawling
MINES' DANGERS & HAZARDS
Shafts (falling through):
The Collar or top of a mine shaft is especially dangerous. The fall down a deep shaft is just as lethal as the fall from a tall building with the added disadvantage of bouncing from wall to wall in a shaft and the likelihood of having falling rocks and timbers for company. Even if a person survived such a fall, it may be impossible to climb back out. The rock at the surface is often decomposed. Timbers may be rotten or missing. So it is dangerous to walk anywhere near a shaft opening, the whole area is often ready and waiting to slide into the shaft along with the curious. A shaft sunk from a tunnel is called a winze. In many old mines winzes have been boarded over. If these boards have decayed, a perfect trap is waiting.
Ladders in most abandoned mines are unsafe. Ladder rungs are missing or broken. Some will fail under the weight of a child because of dry rot. Vertical ladders are particularly dangerous.
Many tunnels have water standing in deep pools or concealing holes in the floor. Pools of water also ware common at the bottom of shafts. It is usually impossible to estimate the depth of the water, and a false step could lead to drowning.
Cave-ins are an obvious danger. Areas that are likely to cave often are hard to detect. Minor disturbances, such as vibrations caused by walking or speaking, may cause a cave-in. If a person is caught he can be crushed to death. A less cheerful possibility is to be trapped behind a cave-in without anyone knowing you are there. Death may come through starvation, thirst, or gradual suffocation.
The Timber in abandoned mines can be weak from decay. Other timber, although apparently in good condition, may become loose and fall at the slightest touch. A well timbered mine opening can look very solid when in fact the timber can barely support its own weight. There is constant danger of inadvertently touching a timber and causing the tunnel to collapse. In any case, the cribbage and cribbing that holds up the wood that holds up the top of the mine is creaking constantly under the tremendous weight, a thousand feet of earth and rock and stone right above you. Then, add to this that every day miners are dynamiting underneath that mountain of rock...
Bad Air / Poisonous Gas:
"Bad Air" contains poisonous gases or insufficient oxygen. Poisonous gases can accumulate in low areas or along the floor. A person may enter such areas breathing the good air above the gases but the motion caused by walking will mix the gases with the good air, producing a possibly lethal mixture for him to breathe on the return trip. Because little effort is required to go down a ladder, the effects of "Bad Air" may not be noticed, but when climbing out of a shaft a person requires more oxygen and will breathe more deeply. The result is dizziness, followed by unconsciousness. If the gas doesn't kill, the fall will. Otherwise, note that the repeated inhalation of coal dust over extended periods of time can result in serious health problems, as, for example, anthracosis (commonly called black lung disease).
Flammable Gas (coal mines):
This happens primarily in coal mines, but could also be a feature of Ghost Rock mines. Sometimes flammable gases (such as methane) are trapped in coal beds, and are released during mining operations. With the use of oil lamps and torches, it's easy to accidentally ignite such gases... and die burned and buried.
Many abandoned mines contain old explosives left by previous workers. This is extremely dangerous! Explosives should never be handled by anyone not thoroughly familiar with them. Even experienced miners hesitate to handle old explosives. Old dynamite sticks and caps can explode if stepped on or just touched.
Old mine tunnels and shafts are among their favorite haunts to cool off in summer, or to search for rodents and other small animals. Any hole or ledge, especially near the mouth of the tunnel or shaft, can conceal a snake.
Coal mines and coal-preparation plants caused much environmental damage in the past. Surface areas exposed during mining, as well as coal and rock waste (which were often dumped indiscriminately), weathered rapidly, producing abundant sediment and soluble chemical products such as sulfuric acid and iron sulfates. Nearby streams became clogged with sediment, iron oxides stained rocks, and "acid mine drainage" caused marked reductions in the numbers of plants and animals living in the vicinity. Potentially toxic elements, leached from the exposed coal and adjacent rocks, were released into the environment. [Acid pools in old mines baby!
Dealing with Danger:
-- No daylight reached this far [deep in the mine] so miners worked by candle light, but dangerous, explosive gases seeped from the rock and if they collected in one place (a pocket), the candle flame could cause an explosion.
-- Even if there was no explosion, the gas was poisonous and could choke the miners to death.
-- Engineers tried to clear the gases by ventilation, making fresh air flow through the workings to carry the gases away.
-- Young "trappers" had to open and close trap doors that sealed the tunnels to control the gas and fresh air flow. Sometimes fires were burned at the bottoms of shafts so that the heated air was drawn out of the pit. There was a danger that this fire could cause an explosion. Furnaces were built at the top of shafts to do the job more safely.
-- Scientists and inventors designed special lanterns, or Safety Lamps. Where possible however, candles were still used because they were cheaper.
Hardrock mining entails diging into solid rock to fine minerals usually in their ore form (the metal plus oxygen). To do this, miners used picks and shovels, rock drills, dynamite and more. Miners dug either shafts that went straight down to follow ore bodies and veins, or tunnels which went somewhat horizontal into rock faces. Shafts usually had some sort of headframe (pictured left) standing above them to support the hoists. Shafts and tunnels were often supported with large timbers to prevent cave-ins. Most shaft or tunnel mines would eventually flood as they hit the water table and water would have to be continually pumped out. Sometimes there was so much water they had to abandon the mines.
Types of Hard Rock Mines
(by Todd Underwood)
Hard rock mines usually fall into one of two categories, tunnels or shafts. Each involves digging and blasting deep into the bowels of the earth. Tunnel hard rock mines begin at the earth's surface and continue horizontally into the rock. Tunnels can extend for miles as they follow the ore. Most tunnels have many side tunnels, or even shafts that are sunk far back in the tunnel. These shafts are called winzes. Exploring Tunnel mines is very dangerous as it its dark and very difficult to see winzes. Many tunnels go back so far into the earth they tap into some of the earth's geothermal resources filling with gas that is toxic to humans. There is also the danger of cave-ins in old shafts that are no longer supported by the rotting wood timbers.
A shaft is a whole in the earth that is dug relatively straight down. Shafts usually have some sort of headframe or large wooden or metal structure at the top of the shaft to support a hoist. Hoists are used to lower men and machinery into the mine and to haul ore out. Many shafts have tunnels dug at different depths throughout the shaft. Getting too close to the side of an abandoned shaft can spell almost certain death. Many of the shafts extend thousands of feet into the earth.
Extracting the Ore
(by Todd Underwood)
The Pick and Shovel Method:
The most simple and inexpensive way of extracting ore for the early miners was the Pick and Shovel method. Miners would swing picks into the rock, slowly breaking it apart. Once enough rock had been removed, it would be shoveled away to be assayed or milled. The pick and shovel method was about the slowest way to extract ore for the miners and prospectors. It also took a lot of strength and would tire them out very quickly. Almost all of the major ore discoveries were done using this method.
As technololy advanced, and the need for more efficient methods of extracting rock prevailed, miners starting drilling the rock with rock drills (pictured left). Once an ore body was disovered, people would move in immediately creating a small town. Equipment and machinery was brought in to start large mining operations. Among this machinery were large steam boilers to power air compressors. These compressors would be used to power the pneumatic (air powered) rock drills. The rock drills looked something like the modern jack hammer and hard very hard bits (pictured right) on the end. Rock drilling was a much faster and more efficient way to extract ore than the pick and shovel method. Sometimes, rock drills would be used to make holes in rock face into which dynamite or other explosives were placed.
Core sampling was done to test or assay the value of a particular area of rock without having to go through the trouble of removing the whole area. Core samplers would be drilled into a rock face and would extract a small core sample. This core sample would usually be a few inches in diameter and up to a few feet long. The core sampler could drill deep into the rock face without having to removed the whole area of rock. Core samples would then be assayed to determine the feasibility of mining in that particular area.
Powering The Mines
(by Todd Underwood)
In the early days and in small operations, simple mule and man power was used for everything. As technology advanced, and operations became larger, the steam engine was introduced. A steam engine consisted of a large boiler. The boiler (pictured here) was a very large cylindrical metal chamber in which steam was produced. Most boilers have either fire tubes or water tubes on the inside of the chamber. Either water was forced through these tubes (pictured below) and the rest of the chamber was filled with "fire" or water filled the chamber and the tubes were filled with the "fire". Wood, coal or coke was used to produce the "fire" or heat that was in turn used to turn the water to steam. From the boiler, the steam went to a cylinder much like a modern gasoline powered car's cylinders. Under pressure, steam forced its way into the cylinder depressing the piston. As the piston was depressed, it turned a crankshaft which could be used to power a hoist, air compressors or pumps.
Wherever possible, water or hydro power was used. If the location of the milling site was near any kind of sizeable reliable moving water, a water wheel would be used to generate power. This water wheel would have many paddles on it and would be partially submerged in moving water. As the water flowed, it would cause the wheel to turn. The wheel was then connected to whatever was needed to be powered.
Transporting the Ore
(by Todd Underwood)
From the Mine to the Outside World:
Once the ore was broken off the rock faces inside the mine, the chunks were shoveled into a transportation system to get it to the outside. If the mine was a shaft mine, the ore was shoveled into an ore bucket which was hauled up to the top of the mine by a winch. This winch or hoist was usually powered by the steam or diesel engines and was also used to get the miners and other equipment in and out of the mines. If the mine was a tunnel mine, the ore was shoveled into an ore car that ran on small train like track. The ore car was pulled on these tracks all the way out of the mine.
From the Mouth of the Mine to the Mill:
Once the ore was at the mine entrance, it was transported to a mill for milling. The type of transportation used here depended on how far the mill was. Many mines had mills in the same town that were nearby the mine making transportation easy. Most of the time, ore was deposited into an ore chute that held tons of ore waiting to be processed. From this chute, the mill which was usually located below the chute to take advantage of gravity, took as much ore per hour as it could process. Sometimes the mines were located on steep cliffs or near the tops of mountains. In these cases, an aerial tramway system was developed, much like a modern ski lift. The only difference is instead of carrying skiers on a seat the tramway carried ore in giant ore buckets. If the mill was located in another city or state, the ore was loaded onto sturdy wagons for transportation.
From the Mill on:
Most mills were not able to concentrate the ore completely to the free metal. In other words, most mills located at the mines and townsites were not able to put a rock in one end and have a gold ingot come out the other. Their job was simply to concentrate the ore enough to save on the shipping. If the ore coming out of the mill was ten times more concentrated than the ore going in, then one wagon load of the processed ore would be equal to 10 wagon loads of the unprocessed ore. This could greatly reduce the riskiness and difficulty of shipping the ore as the ore wagons were a favorite of bandits.
Milling the Ore
(by Todd Underwood)
When a full size stamp mill was not available, arrastras were used to crush the ore. Arrastras were small circular flat areas of land usually about 10-20 feet in diameter with a pole in the center. Attached to the pole was a rod or line running out to a large heavy wheel. A horse or mule was usually attached to the end of the wheel area and would walk around in circles. As the animal walked, the heavy wheel would crush the ore underneath it. Arrastras were a crude way to crush large pieces of rock into much smaller and more manageable sized bits. In later years, iron arrastras (pictured on the right) replaced the wheel method.
Stamp Mills were far more advanced than the early arrastras although they both performed the same function. Stamp mills ranged from one stamp on up to twenty or even fifty stamps all operating together. Each stamp was a large piece of solid iron or other metals attached to a long shaft. These shafts were usually attached to a cam with the other stamps if there were more than one. This cam had usually had a wheel on its end that was driven by a belt system. A steam engine was usually used to turn this wheel which lifted the stamps and dropped them with all their weight on the rocks that were to be crushed. Stamp mills would run 24 hours a day and as one can imagine, are extremely loud. They also tend to shake the ground as they are dropped which can make it feel like there is a continuous earthquake.
ADIT: A horizontal or nearly horizontal entrance to a mine, otherwise known as a tunnel.
ARRASTRA: A Spanish word for a circular rock-crushing device usually powered by a mule.
ASSAY: Measuring proportion of gold or silver content in ore.
CLAIM: A legal document stating the boundries of a proposed mining excavation.
DREDGE: A mining process by which sand in a river bed or stream is scooped up from the bottom and minerals are extracted.
FLOAT: Fragments of ore that had broken off a main vein to become buried rock outcropping.
HEADFRAME: The vertical apparatus over a mine shaft that has cables to be lowered down the shaft for the raising and lowering of ore and men.
HIGH GRADING: A method perfected by miners for carrying off rich ore from the mines and selling it themselves.
HYDRAULIC MINING: A process of washing ore from its bed with powerfull jets of water.
JUMPING A CLAIM: A method of taking over a good mining claim after it had already been staked out by someone else.
MILL: A building in which rock is crushed in order to extricate minerals. Mills are usually constructed on the side of hills and are gravity fed. This leads to the stairstep foundations one can usually see.
MOTHER LODE: The main or primary deposit or vein of a given mineral.
NUGGET: A lump of native or pure gold found in deposits and placer mines.
PLACER: A waterborne deposit of sand or gravel containing heavier minerals like gold that have been eroded from their original bedrock and concentrated as small particles that can be washed out.
PLATTING: Planning or mapping a townsite.
SHAFT: A vertical or nearly vertical opening into the Earth's surface.
SLUICE: an inclined trough, usually made of wood, for washing gold ore. The flow of the water is regulated by flood gates.
SMELTER: A building or complex in which material is melted to be separated from impurities.
STAMP MILL: A machine that crushes rock by means of a big heavy stamp that falls on the rock.
TAILINGS: Waste or refuse left after milling is complete, sometimes referred to as waste dumps.
WASTE DUMP: Waste rock that comes out of a mine.
WINZE: A shaft sunk from an adit.