Subject
Iron ores
5
Oil fields
5
Mines and mineral resources
4
Oil field flooding
3
Petroleum
3
Petroleum Analysis
3
Petroleum engineering
3
Zinc ores
3
Feldspar
2
Flotation
2
Lead ores
2
Lignite
2
Natural gas
2
Oil wells
2
Ore-dressing
2
Ammonium nitrate
1
Boring
1
Celestite
1
Condensate oil wells
1
Copper ores
1
Explosion, 1947
1
Explosions
1
Fluorspar
1
Iron Electrometallurgy
1
Kaolin
1
Mica
1
Oil wells Hydraulic fracturing
1
Oil-shales
1
Petroleum Composition
1
Petroleum industry and trade
1
Phosphate rock
1
Potash
1
Soapstone
1
Talc
1
Texas City (Tex.) History
1
Thermal oil recovery
1
Veins (Geology)
1
Vermiculite
1