App. H— Conversion Table and Glossary • 333 



phosphate, monobasic CcJcium phosphate, monocal- 

 cium phosphate, and tricalcium phosphate. 



Cephalopods: Marine moUusks including squids, octo- 

 puses, and Nautilus. 



Chromic Oxide: A dark green amorphous powder that 

 is insoluble in water or acids. Also known as chrome 

 green. It is commonly used as a standard measure 

 of chromium content in chromite. 



Chromite: An iron-chromic oxide (chrome iron ore). A 

 mineral of the spinel group, and the only mineral 

 mined for chromium. "Chromite" is used synony- 

 mously for chromium ore and concentrates made 

 from the ore used in commercial trade. When refer- 

 ring to the spinel mineral chromite, it is referred to 

 as "chromite mineral." 



Conductivity: The ratio of electric current density to 

 the electric field in a material; the reciprocal of resi- 

 tivity. 



Continental rise: That part of the continental margin 

 that is between the continental slope and the abyssal 

 plain except in areas of an oceanic trench. 



Continental Shelf: The part of the continental margin 

 that is between the shore and the continental slope 

 and is characterized by its very gentle slope. 



Continental Slope: The relatively steeply sloping part 

 of the continental margin that is between the con- 

 tinental shelf and the continental rise. 



Crustacean: Jointed animals with hard shells. This 

 group includes crabs, shrimp, lobsters, and barnacles. 



Deposit-Feeder: An animal that feeds on particulate 

 matter deposited on the seafloor. 



Detritus: Particulate matter resulting from the degener- 

 ation and decay of organisms or inorganic substances 

 in nature. 



Diversity: a measure of the numbers and kinds of spe- 

 cies found in a particular area. 



Dredging: The various processes by which large float- 

 ing machines, or dredges, excavate earth material at 

 the bottom of a body of water, raise it to the surface, 

 and discharge it into a hopper, pipeline, or barge, or 

 return it to the water body after removal of ore 

 minerals. 



Electrolytic Manganese Metal: A relatively pure form 

 of metal produced by the deposition of a metal on the 

 cathode by passing an electric current through a 

 chemical solution of manganous sulfate; at the same 

 time electolytic manganese dioxide (Mn02) is formed 

 at the anode. 



Fauna: the animal life characteristic of a particular envi- 

 ronment or region. 



Ferrochromium: A crude ferroalloy containing chro- 

 mium that is an intermediate iron-chromic product 

 used in the manufacture of chromium steel. 



Ferromanganese Crusts: Crusts of iron and manganese 

 oxides enriched in cobalt that are found on the flanks 



of seamounts, ridges, and other raised areas of ocean 

 floor in the central Pacific. 



Ferromanganese Nodules: Concretions of iron and man- 

 ganese oxides containing copper, nickel, cobalt, and 

 other metals that are found in deep ocean basins and 

 in some shallower areas of the oceanfloor. 



Ferromanganese: A ferroalloy containing about 80 per- 

 cent manganese and used in steelmaking. There are 

 three grades: (1) High-Carbon (Standard) — 74 to 82 

 percent manganese; (2) Medium-carbon — 80 to 85 

 percent manganese; and (3) Low-carbon — 80 to 90 

 percent manganese. 



Filter-Feeder: an animal that feeds on minute organ- 

 isms suspended in the water column by using some 

 screening and capturing (filtering) mechanism. 



Flotation Separation : A method of concentrating ore 

 that employs the principles of interfacial chemistry 

 that separates the useful minerals in the ore from the 

 waste by adding reagents or oUs to a water slurry mix- 

 ture of fine particles of ore and collecting the useful 

 portion that "floats" to the surface in association with 

 the oil or reagent. 



Full Alloy Steel: Those steels may contain between one- 

 half percent to nine percent chromium, but more 

 commonly contain between one and four percent. 

 Chromium is used to impart hardness. 



Furnace-Grade Phosphate Rock: Phosphate rock that 

 assays at 18 to 28 percent phosphorous pentoxide 

 (P2O5). It may be charged directly to electric furnaces 

 to produce slag and ferrophosphorus as byproducts 

 and volatilized elemental phosphorus as the primary 

 product. 



Gangue: The nonmetalliferous or nonvaluable metal- 

 liferous minerals in an ore. 



Geomagnetic: Pertaining to the magnetic field of the 

 earth. 



Geophysics: Study of the earth by quantitative physi- 

 cal methods (e.g., electric, gravity, magnetic, seis- 

 mic, or thermal techniques). 



Grade: The relative quantity or weight percentage of 

 ore-mineral content in an orebody. 



Gradiometry: Measurement of the difference in the 

 magnetic or gravity field between two points, rather 

 than the total field at any given point. 



Gravity Anomaly: The difference between the observed 

 value of gravity at a point and the theoretically cal- 

 culated value. Excess observed gravity is positive and 

 deficient observed gravity is negative. 



Hadfield Manganese Steel: A steel containing 10 to 14 

 percent managanese; resistant to shock and wear. 



Ilmenite: A black, opaque mineral consisting of impure 

 FeTiOa that is the principal ore of titanium. 



Inter ferometry: The precise measurement of wave- 

 length, very small distances and thicknesses, etc. 

 through the separation of light (by means of a sys- 



