- retort furnace
- retort gasoline
- retreating system
- retrogradation
- retrograding shoreline
- return
- rim coast
- rimrock
- rimstone
- rimu
- ring
- ring breakage
- ring burner
- ring cleavage
- ring closure
- ring coal
- ring compound
- ring content
- ring crater
- ring hydrocarbon
- ring isomerism
- ring joint
- ring oiler
- ring ore
- ring reaction
- ring stand
- ring sticking
- ring valve
- ringed
- rising
- rising ground
- Risk capital
- Rissian stage
- river clamp
- river dredge
- river dredger
- river mouth
- rivet steel
- riveted
- riveted tank
- riveting
- reverse circulation
- revolution counter
- reworked
- rhamnitol
- rhodeorhetin
- rhodochrosite
- rhodonite
- rhombic dodecahedron
- rhombohedron
- rhomboidal jointing
- ribbon injection
- ribbon structure
- rice paper
- rich oil
- ricin
- ricket
- riffle
- rig builders
- rig crew
- rig front
- rig iron
- right lay
- right-handedcrystal
- rigid plastics
- roach
- road map
- road network
- road oil
- road tar
- roarer
- roast
- roast heap
- roast yard
- roasted
- roasting chamber
- roasting drum
- roasting installation
- roasting process
- roasting regeneration
- roasting shop
- robbing pillar
- robina
- roble
- rochelle salt
- rochlederite
- rock alum
- rock arch
- rock asphalt
- rock basin
- rock bench
- rock breaker
- rock burst
- rock cartridge
- rock character
- rock constituent
- rock decay
- rock destroyer
- rock drill
- rock drilling