The process of drilling the so-called "popholes" for the purpose of
breaking the larger masses of rock thrown down by the primary blast.
If an operation agitates or disperses dust, it is a secondary source.
See also:primary source
Deposition, around a clastic mineral grain, of material of the same
composition as that grain and in optical and crystallographic continuity
with it, often resulting in crystal faces characteristic of the original
mineral; e.g., the addition of a quartz overgrowth around a silica grain
in sandstone. AGI
Any fan installed underground to ventilate tunnels or workings where the
air current is sluggish. See also:mine ventilation auxiliary fan;
booster fan. Nelson
This cycle is comprised of the processes of weathering, soil formation,
erosion, transportation, and sedimentation. Hawkes, 2
Further comminution of material already reduced to sand sizes in rod or
ball mills. Pryor, 3
Further increase in hardness produced on tempering high-speed steel after
quenching due to precipitation of carbides. CTD
That portion of the haulage system that collects the coal from the various
gathering-haulage delivery points and delivers it to the main haulage
system. Wheeler, H.R.
Lead derived from salvage of wornout end-product items, such as battery
plates, cable covering, pipe and sheet, which are collected, remelted, and
refined in secondary smelters to produce refined lead or various lead-base
alloys. USBM, 7
Metal recovered from scrap by remelting and refining. ASM, 1
Metal recovered from scrap by remelting and refining.
McGraw-Hill, 1
A mineral formed later than the rock enclosing it, usually at the expense
of an earlier-formed primary mineral, as a result of weathering,
metamorphism, or exsolution. AGI
A mineral deposit formed when a primary mineral deposit is subjected to
alterations through chemical and/or mechanical weathering. Secondary
deposits are divided into three groups: sedimentary rocks, secondarily
enriched mineral deposits, and residual or detrital mineral deposits.
Lewis
Porosity developed after the formation of a deposit and resulting from
subsequent fracturing, replacement, solution, or weathering. AGI
See:middlings
A refuse elevator that extracts the second or lighter reject; usually
situated at the discharge end of the washbox. BS, 5
Rocks composed of particles derived from the erosion or weathering of
preexisting rocks, such as residual, chemical, or organic rocks formed of
detrital, precipitated, or organically accumulated materials; specif.,
clastic sedimentary rocks. AGI
a. The period following the primary settling in surface subsidence in
which the surface subsides gradually. This period may continue for many
years or even decades. CF:primary settling
b. Residual subsidence.
The shaft that extends a mine downwards from the bottom of the primary
shaft but not in line with the primary shaft. Spalding