O
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