| Term | Definition |
|---|---|
| Machine mining |
Continuous tunnelling by means of boomheaders, tunnelling machines, TBMs, etc. Distinguished from drill-and-blast.
|
| Main-line jumbo |
Drill jumbo that travels on the main rail line; has man platforms on the sides that can be folded back when not in use. After drillind out the round, the jumbo has to be moved back from the face to a passing track before the mucker can be moved in.
|
| Maintenance |
The act of caring for a facility or system to keep it in working order or to preserve its appearance or value
|
| Maintenance cost |
The cost of carrying out maintenance activities
|
| Market value |
The value an item would be worth if it were sold under normal market conditions
|
| Marketable good |
Good which is the object of exchange in a market
|
| Mass transit |
Provision for the movement of people in an urban area in unstructured groups, e.g. by bus, train, metro, etc
|
| Massive |
In geology, the homogeneous structure of a rock without any planar, directional arrangement of textural or structural features .
|
| Mechanical excavation |
The removal of soil or rock by means of heavy cutting or digging equipment (not hand-held). Distinguished from hand mining and drill-and-blast excavation.
|
| Mechanical parking |
A system for parking cars mechanically. Allows the cars to be parked in less volume per car which can be important in underground parking
|
| Metro |
A rail-based urban mass transport system -- usually with a substantial portion of the route length underground
|
| Microsilica |
See : Silica fume.
|
| Mined construction |
Construction underground with only limited points of access from the surface
|
| Mined tunnel |
A tunnel excavated without removing the overlying rock or soil and, except for shaft connections, open to the surface only at one or both ends during construction.
|
| Miner |
A skilled underground worker.
|
| Misfire, missed hole |
A drill hole in which all part of the explosive has failed to detonate.
|
| Mitigation |
The lessening of a problem by an action or change in design
|
| Mix |
Mixture of materials including cement, aggregates, additives, admixtures, and, possibly fibers used to make concrete or shotcrete (sprayed concrete).
|
| Mixed-face tunnel |
A tunnel requiring excavation of both earth and rock materials in the same heading at the same time. Some owners may extend the definition of rock to include boulders larger that 3 ft in diameter because of similar difficulties of removal.
|
| Moil or gad |
A short steel-pointed chisel wedge or bar for breaking and wedging out rock.
|
