Appendix:Dictionary of Mining, Mineral, and Related Terms/R/6

rubasse
 * a. Fr. A crystalline variety of quartz containing, distributed through it, spangles of hematite that reflect a ruby red. Also spelled rubace. Also known as Ancona ruby; Mont Blanc ruby.

b. Quartz, stained red in cracks to imitate ruby.

rubber
 * a. Guide; binder; conductor.

b. Derb. Fine scythestone; micaceous sandstone. c. A gold-quartz amalgamator in which slime is rubbed against amalgamated copper surfaces. d. A bucking iron or bucking hammer. A broadhead hammer. e. A building brick made from a sandy clay and lightly fired so that it can be readily rubbed to shape for use in gaged work. The crushing strength of such a brick is about 1,000 psi (6.9 MPa).

rubber-bushed couplings
 * Two flanged hubs, one equipped with rubber-bushed holes, the other equipped with pins that mesh with the rubber bushings. To prevent excessive wear, the rubber bushings are bushed with nonferrous bushings, which provide satisfactory contact and wearing surfaces.

rubber conveyor belt
 * A conveyor belt consisting of a central stress-bearing carcass for transmitting power enclosed in rubber or PVC covers to protect the carcass from abrasion and atmospheric changes. The carcass usually consists of plies of cotton duck fabric, but other constructions used are cotton cords, steel cables, and woven fabrics of synthetic fibers, such as rayon, nylon, Orlon, Dacron, fiberglass, and asbestos. The covers are furnished in various thicknesses and qualities of rubber or PVC compounds.

rubber-lined pipes
 * Pipes prepared for handling corrosive liquids in such processes as acid leaching. Also, pumps and impellers handling ore pulps. See also: hydraulic stowing pipe.

rubberstone
 * A sharp-gritted Ohio or Indiana sandstone used for sharpening shoe knives; also known as shoe stone.

rubber-tired haulage
 * The underground use of tractors and dump truck haulage, of battery or diesel type, and battery-driven shuttle cars. See also: trackless tunneling.

rubbing bed
 * In quarrying, a bed consisting of a circular disk of cast iron of varying diameters, rotating on a vertical axis. Marble slabs or blocks held on the surface of this rotating disk, to which sand and water are applied, are worn down to desired dimensions and smoothness.

rubbing stone
 * a. Stone used for rubbing, smoothing, or sharpening; in particular for facing building stones by removing toolmarks.

b. A block of fine-grained abrasive, such as corundum, for the stoning of vitreous enamel.

rubbing surface
 * The total area of a given length of airway; i.e., the area of top, bottom, and sides added together, or the perimeter multiplied by the length.

rubble
 * a. A loose mass of angular rock fragments, commonly overlying outcropping rock; the unconsolidated equivalent of a breccia. CF: talus.

b. Loose, irregular pieces of artificially broken stone as it comes from a quarry. Syn: rubblestone.

rubble concrete
 * Concrete in which large blocks of stone, roughly squared, are placed and arranged roughly in courses, so that they break joint both horizontally and vertically. The stones are placed with not less than 6 in (15 cm) of space between them so that the concrete may be properly rammed. Care is taken that all voids are filled with concrete.

rubbleman
 * In the quarry industry, a foreman who directs and supervises the work of drilling and splitting stone.

rubble masonry
 * Uncut stone, used for rough work, foundations, backing, etc.

rubblerock
 * See: breccia.

rubblestone
 * See: rubble.

rubbly reef
 * Aust. A vein much broken up.

rubellite
 * A pink gem variety of elbaite. Syn: red schorl. See also: elbaite.

ruberite
 * See: cuprite.

rubicelle
 * A yellow or orange-red variety of spinel; an aluminate of magnesium. CF: ruby spinel.

rubidium
 * A soft, silvery-white, metallic element of the alkali metal group, closely resembling potassium. Symbol, Rb. Widely distributed in small quantities in nature. Obtained commercially from lepidolite and from potassium minerals. Forms amalgams with mercury and alloys with gold, cesium, sodium, and potassium. Has been considered for use in space vehicles, and for use in thermoelectric generators.

rubinblende
 * Miners' term for the red silver sulfides pyrargyrite, proustite, and miargyrite. Syn: ruby blende.

rubinglimmer
 * See: lepidocrocite.

Ruble hydraulic elevator
 * A device by which coarse material in placer gravel is separated from the fines and elevated onto a dump.

ruby
 * The red gem variety of corundum, the color due to the presence of chromium in the structure. CF: sapphire.

ruby alumina
 * An abrasive similar to white alumina except ruby red in color because of the presence of chromic oxide.

ruby arsenic
 * An early name for realgar. See also: ruby sulfur.

ruby blende
 * a. A reddish variety of sphalerite. Syn: ruby zinc.

b. See: rubinblende.

ruby cat's eye
 * A girasol ruby with a chatoyant effect. CF: sapphire cat's eye.

ruby copper
 * See: cuprite.

ruby copper ore
 * See: cuprite.

ruby mica
 * An old syn. for goethite.

ruby sand
 * A red-colored beach sand containing garnets, as at Nome, AK.

ruby silver
 * Dark ruby silver is pyrargyrite, and light ruby silver is proustite.

ruby spinel
 * A red gem variety of spinel. CF: almandine ruby; balas ruby; rubicelle.

ruby sulfur
 * See: realgar. Also called ruby arsenic; ruby of arsenic; ruby of sulfur.

ruby tin
 * A red variety of cassiterite.

ruby zinc
 * Miners' term for transparent red sphalerite or zincite. Syn: ruby blende.

rudaceous
 * Said of a sedimentary rock composed of a significant amount of fragments coarser than sand grains; pertaining to a rudite. The term implies no special size, shape, or roundness of fragments throughout the gravel range, and is broader than pebbly, cobbly, and bouldery. Also said of the texture of such a rock.

rudite
 * A general name used for consolidated sedimentary rocks composed of rounded or angular fragments coarser than sand (granules, pebbles, cobbles, boulders, or gravel or rubble); e.g., conglomerate, breccia, and calcirudite. The term is equivalent to the Greek-derived term, psephite. Etymol: Latin rudus, crushed stone, debris, rubble. See also: lutite; arenite.

Ruggles-Coles dryer
 * Rotary drier or kiln, in which material is worked through a horizontal cylinder counter to drying or heating gas blown through by fan.

ruin
 * Eng. A term occasionally employed in familiar description for certain minerals whose sections or cut faces exhibit the appearance of ruined buildings, as ruin agate, ruin marble, etc.

ruin agate
 * A brown variety of agate displaying on polished surfaces markings that resemble the outlines of ruined buildings.

ruin aragonite
 * Brecciated Mexican onyx (aragonite).

ruiniform
 * Minerals having the form or appearance of ruins.

rule of approximation
 * Applicable to placer mining locations and entries upon surveyed lands to be applied on the basis of 10-acre (4-ha) legal subdivisions.

ruling grade
 * The grade that determines tonnage that can be handled by a single locomotive over a particular engine district.

ruling gradient
 * See: limiting gradient.

rumanite
 * See: romanite.

Rumford's photometer
 * A photometer consisting of a rod standing vertically in front of a white screen on which are cast shadows of it by the two light sources whose intensities are to be compared. When the shadows are of equal darkness the ratio of the intensities of the sources equals the square of the ratio of their distances from the screen.

run
 * a. A branching or fingerlike extension of the feeder of an igneous intrusion. Typically spread laterally along several stratigraphic levels.

b. A flat irregular ribbonlike orebody following the stratification of the host rock. c. The direction in which a vein of ore lies. d. A caving in of a mine working. e. Soft ground is said to run when it becomes mud and will not hold together or stand. f. The escape of any flowing material into a tunnel area; it may be sand, gravel, or mud. g. See: grain. h. The length of feed or the advance made by a bit in drilling before it becomes necessary to rechuck the rods or empty the core barrel. CF: pull. i. A round trip in drilling. j. Continuous production, the operation of equipment between major repairs. k. A test made of a process or material.

runaround
 * a. A passage driven in the shaft pillar to enable workers to pass safely from one side of the shaft to the other side. See also: bypass.

b. A conveyor in the form of a circuit as distinguished from a shape in which the carrying and return runs travel substantially the same path.

runaway
 * The uncontrolled downward rush of trams when the haulage rope breaks or becomes detached while the set is being hauled up an incline.

runaway switch
 * Catch point or other automatic diverting switch gear; acts when a mine car runs downgrade or out of control by diverting it to a siding.

runback
 * a. To drill slowly downward toward the bottom of the hole when the drill string has been inadvertently or deliberately lifted off-bottom during a rechucking operation.

b. To retract feed mechanism to its starting position when rechucking.

runback water
 * Scot. Water from a set of pumps that is run back and pumped up again to keep the pump from going "on air" while the other pumps are at work.

run dry
 * To drill without circulating a drilling fluid or mud. CF: dry block.

runic texture
 * Suggested by Johannsen as an alternative to graphic texture, since the intergrown quartz and feldspar resemble runic characters.

run in
 * a. To lower the assembled drill rods, core barrel, and bit, or other types of pipe, casing, or drill string into a borehole.

b. To drill the first few inches slowly at the beginning of a core run or when collaring a borehole. c. The initial period of operation of any mechanism during which the component parts seat themselves.

run-in table
 * See: entry table.

run levels
 * To survey an area or strip to determine elevations.

runner
 * a. Bearer or carrier girder, beam, or bar.

b. A steel-shod poling board, driven into unbroken but loose ground as excavation proceeds. See also: cross poling. c. See: driller. d. A fault slip.

runner box
 * A distribution box that divides the molten metal into several streams before it enters the mold cavity.

runners
 * Vertical timber sheet piles driven to protect an excavation from collapse. See also: guide runner; cross poling.

runner stick
 * A slightly tapering, round stick, used as a pattern for the opening through which molten metal is to be poured into the mold.

running
 * lowering casing, drivepipe, or drill string into a borehole.

b. Earth and rock that will not stand, esp. when wetted, and falls, flows, or sloughs into a borehole or a workplace in a mine.

running block
 * See: traveling block.

running dry
 * The act of drilling without circulating a drilling fluid.

running ground
 * a. Insecure or easily caved wall of excavation.

b. Ground that is incoherent, for example, soils, sand, peat, moss, or waterlogged material. It may be semiplastic or plastic, such as wet clays. All such deposits deform readily under pressure, and relief is obtained by squeezing into openings, such as mine workings. The miner uses the term running ground to indicate the difficulty of support and sometimes of danger. See also: forepoling; quicksand; mud rush.

running kiln
 * A lime kiln that is fed from above and delivers continually below.

running lift
 * Light mine pump used in sinking, which can be raised or lowered in shaft as required.

running measures
 * Eng. Sand and gravel containing much water.

running off
 * In founding, the opening of the taphole of a blast furnace and allowing of the molten metal to flow out to the molds.

running rope
 * A flexible rope of 6 strands, 12 wires each, and 7 hemp cores.

running sand
 * a. An unconsolidated sand. See also: run.

b. Quicksand.

running sheave
 * A sheave used as a single-pulley traveling block.

runoff
 * a. That part of precipitation appearing in surface streams.

b. The collapse of a coal pillar in a steeply pitching seam, caused either naturally or by a small shot in connection with pillar robbing. The pillar is said to have run off.

runoff coefficient
 * The percentage of precipitation that appears as runoff. The value of the coefficient is determined on the basis of climatic conditions and physiographic characteristics of the drainage area and is expressed as a constant between zero and one (Chow, 1964). Symbol: C.

runoff pit
 * Catchment to which spillage can gravitate should it be necessary to dump the contents of mill machines such as classifiers, thickeners, and slurry pumps. Provided with a reclaiming pump so that the contents can be returned to the appropriate part of the flow line.

run of lode
 * Corn. The direction or course of a lode.

run-of-mill
 * Ore finally accepted by a mill for treatment, after waste and dense-media rejection. Original mined ore (run-of-mine) is ore as severed and hoisted. Syn: mill-head ore.

run-of-mine
 * a. The raw mined material as it is delivered by the mine cars, skips, or conveyors and prior to treatment of any sort. See also: pithead output.

b. Average grade of ore produced from a mine. c. Said of ore in its natural, unprocessed state; pertaining to ore just as it is mined.

runout
 * a. The unintentional escape of molten metal from a mold, crucible, or furnace.

b. In mineral processing, the dumping of pulp before the contained solids pack down and choke a stalled mechanism in the event of a breakdown or a power failure.

runout fire
 * A forge in which cast iron is refined.

run-to-waste
 * Drill cuttings that are not collected or saved as a sludge sample and are allowed to collect in the sump; also, the return drill-circulation fluid not returned to a sump for recirculation.

Ruoss jig
 * A jig used chiefly on tin dredges to treat the undersize from the main revolving screen. It differs from the Harz jig in that there is no longitudinal division and the screening compartment extends over the whole surface of the jig; the plungers are located in the hutch below the screen are set in a vertical plane and reciprocate horizontally.

rupture
 * Deformation characterized by loss of cohesion. Frequently flow grades into rupture, with a progressive loss of cohesion, until complete separation occurs. See also: fracture.

rupture envelope
 * See: Mohr envelope.

rupture factor
 * The term is used with reference to brittle materials; i.e., materials in which failure occurs through tensile rupture rather than through excessive deformation. For a member of given form, size, and material, loaded and supported in a given manner, the rupture factor is the ratio of the fictitious maximum tensile stress at failure, as calculated by the appropriate formula for elastic stress, to the ultimate tensile strength of the material as determined by a conventional tension test.

rupture line
 * See: Mohr envelope.

rupture strength
 * The differential stress that a material sustains at the instant of breaking, or rupture. The term is normally applied when deformation occurs at atmospheric confining pressure and room temperature.

rupture zone
 * The region immediately adjacent to the boundary of an explosion crater characterized by excessive in-place crushing and fracturing where the stresses produced by the explosion exceeded the ultimate strength of the medium. CF: plastic zone.

rush
 * a. A stampede of prospectors and miners into a new discovery area.

b. A place where gold is found in abundance.

rush gold
 * See: rusty gold.

russellite
 * Corn. A tetragonal mineral, Bi (sub 2) WO (sub 6) ; a yellow alteration product with native bismuth and wolframite.

Russell process
 * A metallurgical process similar to the Patera process, except that cuprous sodium hyposulfite is used in addition to the sodium hyposulfite.

Russia iron
 * A high-grade, smooth, glossy sheet iron, not liable to rust; once made by a process that was long a secret with Russian manufacturers. The sheets were subjected to severe hammering in piles with powdered charcoal between them.

Russian crystal
 * A colorless variety of gypsum.

rust
 * a. A corrosion product consisting of hydrated oxides of iron. Applied only to ferrous alloys.

b. A mixture of iron filings, ammonium chloride, and sometimes sulfur, moistened and placed between iron surfaces, where it hardens by oxidation, and forms a solid joint called a rust joint. c. An English term for a black shale discolored by ocher.

rustler
 * In anthracite and bituminous coal mining, a general term applied to any worker who looks after the haulage system, performing the necessary work by which mine cars are raised and lowered to and from the mine surface. May be designated according to job, as clipper; rollerman.

rustless process
 * A process for the manufacture of stainless steels in an electric furnace that uses a chrome ore as a source of chromium with or without the addition of silicoferrochromium, conjointly with stainless steel scrap. The hearth of the furnace is lined with chromite bricks.

rusty gold
 * Cal. Free gold, that does not readily amalgamate, the particles being covered with a siliceous film, thin coating of oxide of iron or manganese, etc. Syn: rush gold.

rute
 * In mining, threadlike veins of ore.

ruthenium
 * A hexagonal mineral, Ru.

rutherfordine
 * An orthorhombic mineral, UO (sub 2) (CO (sub 3) ) ; radioactive; earthy yellow; secondary.

rutilated quartz
 * Sagenitic quartz characterized by enclosed needles of rutile. CF: fleches d'amour; sagenite. Syn: Venus hairstone. See also: sagenitic quartz.

rutile
 * a. A tetragonal mineral, TiO (sub 2), in which titanium replaces iron; trimorphous with anatase and brookite; prismatic; in amphibolites, ecologites, granite pegmatites, veins, and placers; a source of titanium; also a gemstone. Syn: red schorl; titanic schorl. See also: titanium dioxide; zircon group.

b. The mineral group argutite, cassiterite, paratellurite, plattnerite, pyrolusite, rutile, and stishovite.

R wave
 * See: Rayleigh wave.

Rziha's theory
 * A mine subsidence theory that is a variant or extension of the vertical theory. In this theory, allowance is made for movements beyond the undermined area, but the dip of the beds is considered to be of little or no influence. Rziha maintained that if rock is undercut, it will stay undisturbed if cohesion exceeds gravity and will fall if gravity exceeds cohesion.