N nablock nacre nacreous nacrite nadir nadorite naetig nagyagite nahcolite naif nail nailhead spar naked name of lode nanotesla Nansen bottle nantokite naphtha naphtha gas naphthode Napierian logarithm napoleonite nappe napthoid narrow narrow gage narrow place narrow stall narrow work narrow working nascent Nasmyth hammer Na-spar National coarse thread National Electrical Code national grid national grid coordinates Nationalization Act National Physical Laboratory native native copper native element native mercury native nickel-iron native water natrite natrium natrochalcite natrojarosite natrolite natromontebrasite natron natrona natron granite nattle natural air crossing natural asphalt natural carbon natural cement natural coke natural convection natural diamond natural Earth current natural face natural floatability natural frequency natural frequency of a foundation natural frequency vibrating conveyor natural gamma radiation detector natural gamma-ray logging natural gas natural glass natural logarithm naturally bonded molding sand natural ore natural ore concentrate natural paper natural resin natural sand natural scale natural slope natural splitting natural stress relief natural ventilating pressure natural ventilation nauckite naumannite nautical chart nautical measure nautical mile navajoite Navier's hypothesis NCB NCB boring tower NCB recorder neap tide nearest neighbor interpolation method near-gravity material near-mesh near-mesh material neat neat cement neat lines nebulite neck needle needle bearing needled needle instrument needle ore needles needle traverse negative crystal negative element negative elongation negative moment negative rake negligence neighborite nekton Nelson Davis separator nelsonite nematoblastic neokerogen neolite Neolithic neomesselite neomineralization neomorphic neoprene plug closure nepheline nepheline syenite nephelinite nephelinitoid nephelinization nephelometry nephrite neptunian dike neptunian theory neptunism neptunite neritic neritic zone Nernst film nero-antico nesquehonite ness nest nested variogram model net net calorific value net-corrected fill net cut net fill nether nether roof nether strata net slip net texture Nettleton method net unit value network network deposit network structure Neuenburg saw neuk Neumann lamellae neuropteris neutral atmosphere neutral axis neutral equilibrium neutralize neutral lining neutral point neutral pressure neutral refractory neutral salt neutral salt effect neutral stress neutral surface neutral zone neutron neutron density neutron-gamma log neutron log neutron logging Nevadan orogeny nevyanskite Newark Supergroup Newaygo screen newjersite Newlyn datum Newmann hearth new miner training new sand new scrap Newtonian fluid Newton's law of gravitation New York rod N-frame brace ngavite niccolite Nicholls' technique nickel nickel antimony glance nickel bloom nickel carbonyl nickel glance nickel green nickeliferous nickeline nickel iron nickelite nickel ocher nickelous oxide nickel oxide nickel plating nickel pyrite nickel-skutterudite nickel vitriol nicking nickings nicol nicolite Nicol prism Niggli's classification night emerald night pair night shift nigritite nil nine-inch straight nine-point sample ningyoite niobite niobium niobium boride niobium nitride nip niperyth nipple Ni-resist nital niter niter cake nitrate nitratine nitrification nitro nitrocalcite nitrocellulose nitrocotton nitrogelatin nitrogen nitrogen fixation nitroglycerin nitroglycerin explosive nitroglycerin powder nitrohydrochloric acid nitrolite nitromagnesite nitromuriatic acid nitrostarch explosive nitrosubstitution nitrosulfuric acid nitrous oxide niveau surface noble noble gas nobleite noble metal no-cut rounds nodular nodular cast iron nodular structure nodule nodulizing noise noise level noise reduction rating nolanite nominal area nominal bandwidth nominal capacity nominal price nominal screen aperture nominal screen size nominal size nomogram nomograph nonangular unconformity nonasphaltic pyrobitumen nonbanded coal non-Bessemer ore noncaking coal noncaving method noncoal mine noncoking coal noncombustible nonconformable nonconformity nonconsumable-electrode arc melting noncore bit noncore drilling noncoring bit nondestructive testing nondiamond core drill nonel nonelectric blasting nonelectric delay blasting cap nonferrous nonferrous alloy nonferrous metallurgy nonferrous metals nonflowing well nonfreezing explosive nongraded sediment nonhardening salt nonluminous flame nonmagnetic rod nonmagnetic steel nonmetal nonmetallic nonmetallic armor nonmetallic mineral nonmetallic minerals non-metallic minerals non-Newtonian flow nonnitroglycerin explosive nonpareil brick nonpermissible explosive nonpolarizable electrode nonproductive formation nonrotating rope nonsegregating chute nonselective mining nonsequence nonsignificant anomaly nonsparking tool nonspin cable nonspin differential nonspinning rope nonstranded rope nonstructural nontabular deposit nontectonite nontronite nonuniform flow nonvitreous nonvitrified nonweathering coal nonwetted Norbide nordite norite norm normal normal air normal arc normal calorie normal corrosion normal depth normal dip normal displacement normal fault normal field normal fold normal haul normalized steel normalizing conveyor normally consolidated normal moisture capacity normal pressure normal price normal scale normal shift normal solution normal stress normal stress component normal temperature normal theory normal travel-time curve normative normative mineral norm system Norsk-Staal process norstrandite north end north-seeking pole Norwalt separator Norwegian cut nose nosean nose in noselite nose out nose pipe nosin nosite notch notch effect notcher notching notch sensitivity ratio not previously known to exist Nottingham system noumeite novackite novaculite nowel noxious gas nozzle brick nozzleman NPN process NQ N rod bit N-truss nubber nuclear-assisted mining nuclear log nuclear magnetism log nuclear magnetometer nuclear powerplant nuclear reaction nuclear resonance magnetometer nucleation nucleometer nucleon nucleus nuclide Nuflex nugget nugget effect nugget model nuisance dust Nujol Nullagine Series nullah Numidian marble Nummulite limestone Nusse and Grafer PIV/6 drilling machine nut coal nutcracker NW NX nylon nylon belt nystagmus oikocryst oil agglomeration oil base oil-bearing shale oiled oiler oilfield winch oil flotation oil of vitriol oil pot oil pump oil shale oilstone oil-temper okenite old age oldhamite Oldham stone duster Oldham-Wheat lamp old hole oldland Old Red Sandstone old scrap old silver old waste old working oleander-leaf texture oleic acid oligist oligist iron Oligocene oligoclase oligonite oligosiderite oligotrophic peat olivenite Oliver filter olivine olivine rock olivinite olivinoid olivinophyre ollenite O.L.P. steel process ombrogenous peat omnibus omnidirectional hydrophone omphacite o.m.s. on air oncosimeter onegite one on two one-part line one-piece set one shot one-shot exploder one-spot strip mining one-way ram one-way ventilation onion-skin weathering onlap on line on long awn onofrite on plane onsetter onsetting machine on short awn on sights Ontarian on-the-solid on the track onyx onyx agate onyx marble oolite oolith oolitic oolitic limestone oolitic texture ooze opacite opacity opal opalescence opaline opalite opalized wood opaque opaque-attrite opaque attritus opaque-durit open area opencast opencast method opencast mine opencast working open circuit open-circuit mill open-crib timbering opencut opencut mine opencut mining open-drive sampler open end method opener hole open fault open fire open fold open front open-graded aggregate open hearth open-hearth furnace open-hearth process open-hearth steel open hole opening opening out openings opening shot opening stock open lagging open light open off openpit mine openpit mining openpit quarry open pot open rock opens open-sand casting openset open shop open split open stope open-stope method open-tank method open timbering open-top carrier open-top tubbing open traverse open working operating carrier operating cost operating engineer operating point operation operational capacities operative temperature ophicalcite ophiolite ophite ophitic optical anomaly optical calcite optical centering device optical character optical constant optical crystallography optical diffraction optical flat optical glass optical mineralogy optical property optical pyrometer optical sign optical square optical twinning optic angle optic-axial angle optic axis optics optic sign optimization optimum depth of cut optimum moisture content option optional-flow storage opx oral agreement to locate orange heat orangepeel orangepeel sampler orbicular orbicular structure orcelite ordered solid solution order of crystallization order of persistence order of reaction ordinary kriging ordinary ray ordinate ordnance bench mark ordnance survey ordonezite ore ore band ore-bearing fluid ore bed ore bin ore blending ore block ore blocked out ore boat orebody ore boil ore bridge ore-bridge bucket ore car ore chute ore cluster ore control ore crusher ore delfe ore deposit ore developed ore developing ore dike ore district ore dressing ore expectant ore face ore-forming fluid ore genesis ore geology oregonite ore grader ore guide ore hearth oreing down ore in sight ore intersection ore magma ore microscope ore microscopy ore mineral ore partly blocked orepass ore personal property ore pipe ore plot ore pocket ore preparation ore province ore reserve ore sampling ore separator ore shoot ore sill ore stamp ore-storage drier man ore strand ore trend ore vein ore washer ore zone Orford process organ organic organic ash organic colloid organic deposit organic efficiency organic soil organic sulfur organic test organogenic organolite orichalcum orient oriental oriental alabaster oriental cat's-eye oriental powder orientation orientational twinning orientation survey oriented oriented bit oriented core oriented core barrel oriented diamond oriented sample oriented specimen oriented survey orienting coupling orientite orifice orifice meter orifice of passage origin original dip original hole original lead original mineral ormolu ornamental stone ornansite orocline orogen orogenesis orogenic orogeny orometer oronite O'Rourke car switcher orphaned mine land orpiment Orsat gas-analysis instrument orthite ortho- orthoamphibole orthochlorite orthoclase orthoclase gabbro orthoclasite orthoclastic orthodolomite orthodome orthoferrosilite orthogneiss orthogonal orthoguarinite orthohydrous maceral orthokalsilite ortholimestone orthomagmatic orthomagmatic stage orthomarble orthomic feldspar orthophotography orthophyric orthopinacoid orthoprism orthopyroxene orthoquartzite orthorhombic orthorhombic system orthoschist orthoscope orthose orthotectic orthotectic stage orthotropic Orton cone oryctognosy oryctologist oryctology Osann's classification osarizawaite oscillating beam oscillating conveyor oscillating feeder oscillating grease table oscillation oscillator plate oscillator quartz oscillatory twinning oscillatory zoning oscillogram oscillograph oscilloscope osmite osmium osmosis osteolite ostracod otavite other rock in place other valuable deposits otisca process Otisca-T process Otto cycle Ouachita stone oued outburst outby outcrop outcrop map outcropping outcrop water outdoor stroke outer continental shelf outer core outer gage outer stone outfall outlay outlet outlier out of gage out-over output output device output shaft outrigger outside angling outside clearance outside face outside foreman outside stone outside tap outside upset outside wall outside work outslope outstation outtake oval socket oven overaging overall concentration overall drilling time overall efficiency overall fan efficiency overall reduction ratio overall ventilation efficiency over-and-under conveyor overarching weight overbreak overbreaking overburden overburden bit overburden drilling overcast overcasting overcharging overconsolidated soil deposit overcrossing overcurrent relay overcut overcutting machine overdense medium overdrilling overdrive overfired overfiring overflow stand overgate overgrinding overhand cut-and-fill overhand stope overhand stoping overhand stoping and milling system overhand stoping on waste overhand stoping with shrinkage and delayed filling overhand vertical slice overhang overhaul overhead cableway overhead conveyor overhead monorail overhead-rope monorail overhead ropeway overhead shovel overhead traveling crane overhead trolley conveyor overlap overlap auxiliary ventilation overlap fault overlay overlay tracing overload overloader overmining overpoled copper overprint override overriding royalty overrope overrope haulage overrun overrun brake overrunning clutch oversaturated rock overshot overside oversize oversize control screen oversize core oversize coupling oversize hole oversize rod overspringing overstressed area Overstrom table over-the-road hauling overthrust overthrust block overthrust fault overthrust nappe overthrust plane overthrust sheet overthrust slice overtime overtopping overtravel overtub system overturned overturning skip overventilation overvoltage overvoltage relay overwind overwinder overwinding overwind switch ovulite Owen process Owen's borehole surveying instrument Owen's jet dust counter oxacalcite oxalite oxammite oxialyphite oxidate oxidation oxidation of coal oxide oxide discoloration oxide mineral oxide of iron oxidized deposit oxidized ore oxidized zone oxidizer oxidizing flame oxidizing fusion oxidizing smelting oxonite oxyacetylene oxyacetylene cutter oxychloride cement oxygen oxygen balance oxygen-Bessemer oxygen consumption oxygen deficiency oxygen-deficient atmosphere oxygen-enriched atmosphere oxygen-flash smelting process oxygen-free copper oxygen impingement process oxygen index oxygen lance oxygen process oxygen steel oxyhornblende oxyhydrogen oxyhydrogen blowpipe oxymagnite oxyphile ozarkite ozocerite ozone ozonizer