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Geology topics

D.L. Mosier

Publications and source records attributed to D.L. Mosier.

6 recordsLinked to original sources
USGS1986

Relationship of grade, tonnage, and basement lithology in volcanic-hosted epithermal precious-and base-metal quartz-adularia-type districts

Examination of grades, tonnages, and basement rocks for 88 epithermal precious- and base-metal quartz-adularia-type districts in North, Central, and South America, and Japan reveals that the type of basement rock below the mineralized veins is useful for predicting grade and size of deposits. Epithermal districts overlying basement with salt and evaporites, or rocks with trapped sea water, have a median tonnage (production and reserves) of 1.4 million metric tons and median grades of 1.5g/t Au, 130g/t Ag, 2.5%Pb, 1.7%Zn, and 0.16%Cu. Districts overlying sedimentary basements have a median tonnage of 0.77 million metric tons and median grades of 7.5g/t Au, 110g/t Ag, <0.025%Zn, <0.005%Cu, and <0.001%Pb. Districts overlying igneous basements have a median tonnage of 0.3 million metric tons and median grades of 5.9g/t Au, 38g/t Ag, <0.25%Zn, <0.002%Cu, and <0.003%Pb. This investigation suggests that basement rocks affect vein components in epithermal precious- and base-metal quartz-adularia-type deposits.

Mining Geology↗
USGS1981

A review of regional mineral resource assessment methods

Over 100 papers on regional mineral resource assessment of nonfuels are classified according to method(s) used and form(s) of product in order to help identify possible methods for future assessments. Types of products that have been used include: tons of metal; tons of rock and associated grade; gross value; potential; number of deposits; probability of one or more deposits; tons of rock, grade, and number of deposits by type; potential supply; and net value. Assessment methods considered are: time-rate, crustal abundance, cumulative tonnage versus grade, simple subjective, complex subjective, Bayesian, frequency, trend, geometric probability, multiple regression, discriminant analysis, modified component, multivariate logistic, cluster analysis or pattern recognition, and simulation.Selection of a method to be employed in an assessment should be based on: (1) appropriateness of the product to the problem, (2) limitations in resources, such as information or time available for the assessment, (3) the level of uncertainty and acceptability of biases in the assessment, and (4) the need for verification of results and acceptance of the method.

Economic Geology↗