Next page Previous page

Merrill-Crowe process

Removal of gold from pregnant cyanide solution by deoxygenation, followed
by precipitation on zinc dust, followed by filtration to recover the
resultant auriferous gold slimes. Pryor, 3

Merrill filter

A type of plate and frame pressure filter.

merrillite

a. High-purity zinc dust used to precipitate gold and silver in the
cyanide process.
b. See:whitlockite

Merrit plate

See:bloomery

mersey yellow coal

See:tasmanite

merwinite

A monoclinic mineral, Ca3 Mg(SiO4 )2 ; colorless to
pale green.

mesa

An isolated, nearly level landmass standing distinctly above the
surrounding country, bounded by abrupt or steeply sloping erosion scarps,
and capped by a layer of resistant, nearly horizontal rock (often lava).
CF:plateau

Mesabi non-Bessemer ore

See:natural ore

mesa-butte

See:butte

Mesa Grande tourmaline

Fine-quality tourmaline from a pegmatite near Mesa Grande, San Diego
County, CA.

mesh

a. In ventilation, a series of airways that form a closed loop.
Roberts, 1
b. The screen number of the finest screen of a specified standard screen
scale.
c. The number of apertures per unit area of a screen (sieve).

mesh aperture

The dimension or dimensions of the aperture in a screen deck, usually with
a qualification as to the shape of aperture; e.g., round-hole,
square-mesh, and long-slot. BS, 5

mesh fraction

That part of a material passing a specified mesh screen and retained by
some stated finer mesh. Henderson

mesh liberation size

The particle size at which substantially all of the valuable minerals are
detached from the gangue minerals. Fuerstenau

mesh number

The designation of size of an abrasive grain, derived from the openings
per linear inch in the control sieving screen. Syn:grit number
ACSG, 2

mesh of grind

Optimum particle size resulting from a specific grinding operation, stated
in terms of percentage of material passing (or alternatively being
retained on) a given size screen. The mesh of grind is the liberation mesh
decided on as correct for commercial treatment of the material. Abbrev.,
m.o.g. Pryor, 3

mesh structure

A structure resembling network or latticework that is found in certain
alteration products of minerals. Also called net structure; lattice
structure. Standard, 2; Fay

mesh texture

a. A texture resembling a network, caused by the alteration of certain
minerals; e.g., the serpentinization of olivine.
Syn:reticulate texture
b. An interlacing network of microveinlets of fibrous serpentine enclosing
cores of more weakly birefringent cryptocrystalline serpentine in which
relict remnants of olivine may survive. Also called net structure; lattice
structure.

meso-

A prefix meaning middle. CF:cata-; meta-. AGI

mesocratic

Applied to igneous rocks that are intermediate between leucocratic and
melanocratic rocks; they contain 30% to 60% dark minerals.
CF:melanocratic; leucocratic. CTD

mesocrystalline

Said of the texture of a rock intermediate between microcrystalline and
macrocrystalline; also, said of a rock with such a texture. AGI