At the end of the 13th century capital money started going towards mining and more sophisticated machinery is installed in underground mining, which resulted in reaching great depths. The wider application of horse-power was necessary for draining water out of these deep shafts. By the 14th century, the majority of the accessible ore deposits were depleted meaning more advanced technological achievements were introduced in order to keep up with the demand in metal. The alchemical laboratory, separating precious metals from the baser ones they are typically found with, started becoming more popular, one of the methods used being acid parting in separating of gold from silver.
There are two different types of rocks to mine through: soft rock and hard rock.
Methods used on soft rock are:
Longwall mining – A set of mining equipment consisting of a coal shearer mounted on conveyor operating underneath a series of self-advancing hydraulic roof supports. Almost the entire process can be automated. Longwall miners extract “panels” – rectangular blocks of coal as wide as the face the equipment is installed in, and as long as several kilometres. Powerful mechanical coal cutters (shearers) cut coal from the face, which falls onto an armoured face conveyor for removal. Longwalls can advance into an area of coal, or more commonly, retreat back between development tunnels (called “gateroads”). As a longwall miner retreats back along a panel, the roof behind the supports is allowed to collapse in a planned and controlled manner.
Room-and-pillar mining– Room and pillar mining is commonly done in flat bedded ores. Pillars are left in place in a regular pattern while the rooms are mined out. In many room and pillar mines, the pillars are taken out, starting at the farthest point from the mine haulage exit, retreating, and letting the roof come down upon the floor. Room and pillar methods are well adapted to mechanization, and are used in deposits such as coal, potash, phosphate, salt, oil shale, and bedded uranium ores.
Methods used on hard rock are:
Cut and fill mining- mining used in steeply dipping or irregular ore zones, in particular where the hanging wall. The ore is mined in horizontal or slightly inclined slices, and then filled with waste rock, sand or tailings. Can be consolidated (filled in) with concrete, or left unconsolidated. Cut and fill mining is an expensive but selective method, with low ore loss and dilution.
Drift and fill is similar to cut and fill, except it is used in ore zones which are wider than the method of drifting will allow to be mined. In this case the first drift is developed in the ore, and the hole is backfilled using consolidated fill (filled back in). The second drift is driven adjacent to the first drift. This carries on until the ore zone is mined out to its full width, at which time the second cut is started atop of the first cut.
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