See:angling
One-half the total difference between the outside diameter of any piece of
downhole equipment and the inside diameter of the borehole. Long
The peripheral portion or that part of a bit crown, roller bit cutter, or
any cutting edge of a bit in contact with the walls of a borehole while
drilling. Long
In bituminous coal mining, a person who supervises all operations at the
surface of a mine. DOT
See:outer stone
See:bell tap
The act or process of thickening a length of tubing at its ends by
increasing its outside diameter without changing the inside diameter; a
length of tubing or drill rod so processed. See also:upset
Long
That part of a bit crown, bit shank, reaming shell, core barrel, drill
rod, casing, or other piece of downhole equipment that when in use, comes
in contact with the wall of a borehole. Long
Drilling operations conducted on the surface, as opposed to drilling done
in underground or enclosed workplaces. Long
The face of the spoil or embankment sloping downward from the highest
elevation to the toe.
A location which provides local monitoring and control, and provides a
communications interface between a sensor and the trunk connected to a
central station computer. Also called field data station. SME, 1
The passage by which the ventilating current is taken out of the mine; the
upcast. The return air course. An outlet. Fay
A fishing tool used to recover broken drill rods from a borehole.
Long
A chamber in which substances are artificially heated for the purposes of
baking, roasting, annealing, etc.; specif.: (1) a kiln, such as a coke
oven; and (2) a leer, which is used in glassmaking. Standard, 2
Aging at a higher temperature, or for a longer time, or both, than
required for critical dispersion, thus causing particle agglomeration of
the precipitating phase and, as a result, loss of strength and hardness.
See also:aging
The ratio of pithead output in tons (P) to length of main haulage roads in
yards (L) or tons per yard of main haulage roads; i.e., P/L.
See also:concentration of output
The sum of the times required for actual rock drilling, setting up and
withdrawal, moving drills from hole to hole and machine delays. The
overall drilling time is a better basis for estimating drilling efficiency
than penetration speed alone. Nelson
a. Of an air compressor, the product of the compression efficiency and the
mechanical efficiency. Fay
b. Ratio of power output of an engine to the power input; the measure of
the difference between indicated and brake horsepower. Brantly, 2
The ratio of the horsepower in the air to the horsepower absorbed by the
driving motor of the fan. BS, 8
With reference to a crusher, mean size of feed/mean size of product.
See also:reduction ratio
overall ventilation efficiency
The ratio between the air horsepower and the indicated horsepower of a
driving unit. The percentage is expressed by air horsepower x
100/indicated hp of driving unit. Measurements are taken of the air
pressure and volume in the fan drift, and the power absorbed by the
driving unit. See also:volumetric efficiency; thermometric fan test.
Nelson