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James Bachelder Cathcart

Publications and source records attributed to James Bachelder Cathcart.

At least 19 recordsLinked to original sources
USGS1984

Phosphate rock resources of the United States

In 1980, the United States produced about 54 million tons of phosphate rock, or about 40 percent of the world's production, of which a substantial amount was exported, both as phosphate rock and as chemical fertilizer. During the last decade, predictions have been made that easily ruinable, low-cost reserves of phosphate rock would be exhausted, and that by the end of this century, instead of being a major exporter of phosphate rock, the United States might become a net importer. Most analysts today, however, think that exports will indeed decline in the next one or two decades, but that resources of phosphate are sufficient to supply domestic needs for a long time into the future. What will happen in the future depends on the actual availability of low-cost phosphate rock reserves in the United States and in the world. A realistic understanding of future phosphate rock reserves is dependent on an accurate assessment, now, of national phosphate rock resources. Many different estimates of resources exist; none of them alike. The detailed analysis of past resource estimates presented in this report indicates that the estimates differ more in what is being estimated than in how much is thought to exist. The phosphate rock resource classification used herein is based on the two fundamental aspects of a mineral resource(l) the degree of certainty of existence and (2) the feasibility of economic recovery. The comparison of past estimates (including all available company data), combined with the writers' personal knowledge, indicates that 17 billion metric tons of identified, recoverable phosphate rock exist in the United States, of which about 7 billion metric tons are thought to be economic or marginally economic. The remaining 10 billion metric tons, mostly in the Northwestern phosphate district of Idaho, are considered to be subeconomic, ruinable when some increase in the price of phosphate occurs. More than 16 billion metric tons probably exist in the southeastern Coastal Plain phosphate province, principally in Florida and North Carolina and offshore in the shallow Atlantic Ocean from North Carolina to southern Florida. This resource is considered to be hypothetical because it is based on geologic inference combined with sparse drilling data. Total resources of phosphate rock in the United States are sufficient to supply domestic demands for the foreseeable future, provided that drilling is done to confirm hypothetical resources and the chemistry of the deposits is determined. Mining and beneficiation techniques will have to be modified or improved, and new techniques will have to be developed so that these deposits can be profitably exploited.

Circular↗
USGS1974

Geology and mineralogy of phosphate rock in the Bambui group near Cedro do Abaete and vicinity, Minas Gerais, Brazil

Discontinuous lenticular masses of phosphate rock are present near or at the contact between the green mudstone and the underlying red and yellow clay-stone units of the Serra da Saudade Member of the Rio Paraopeba Formation of the Bambui Group of late Precambrian to early Paleozoic age. The lenses are as much as 8 meters thick and 400 meters long. The phosphate rock is folded and faulted and is overlain by flat-lying rocks of Cretaceous age. The phosphate mineral is a carbonate fluorapatite, but only a small amount of C0 2 substitutes for PO 4 . Crystalline apatite in veinlets is clearly younger than the groundmass apatite, and contains almost no C0 2 . Surficial parts of the phosphate lenses have been altered to a rock characterized by aluminum phosphate. Samples of the green mudstone contain muscovite-illite, quartz, and what is believed to be glauconite. Samples collected adjacent to the phosphate lenses also contain veinlets of apatite or wavellite. Chemical analyses of the phosphate rock show that it contains from 16 to 35 percent P 2 0 5 , and all samples are deficient in Ca0 relative to P 2 0 5 , indicating that some of the phosphate in all samples is combined with alumina. The samples contain as much as 8 percent K 2 0 in the minerals muscovite-illite or glauconite. All the samples collected are extremely fine grained. The rocks are laminated and show the effects of slight deformation; for example, crumpled bedding, offset veinlets, and slight development of muscovite along bedding planes. The phosphate probably is not economically important on the world market, but possibly could be used locally for direct application depending on agricultural lands.

Minas Gerais↗
USGS1967

Phosphate rock in Colombia - a preliminary report, with a section on the phosphate occurrence at Turmeque

Exploration for phosphate rock in Colombia was successfully carried out in 3 1/2 months by the U.S. Geological Survey and the Inventorio Minero of the Servicio Geologico Nacional, under the auspices of the U.S. Agency for International Development. A modern theory of exploration based on model studies of phosphorite deposits is that phosphate is deposited in the miogeosyncline adjacent to the foreland or craton, where parts of the ocean are deep, where deposition of clastic material is at a minimum, and where upwelling currents deposit a suite of rocks characterized by chert, black shale, carbonate rock, and phosphorite. Although phosphate is found in rocks of all geologic periods, economic deposits are known only in certain of: the periods--one of these being the Late Cretaceous. As previous work had demonstrated that phosphate is present in Colombia only in rocks of Cretaceous age, and is most abundant in rocks of Late Cretaceous age--the La Luna Formations and Guadalupe--in the Cordillera Oriental, work was accordingly confined to the Cordillera Oriental and to rocks of Late Cretaceous age. Particular emphasis was paid to facies changes in the miogeosyncline; the field investigation pointed to the area in Norte de Santander where the best phosphorite was found. Phosphate deposits were found in both the geosynclinal and the platform facies in Upper Cretaceous rocks spread through a large area of the Cordillera Oriental, from Huila in the south to Norte de Santander in the north, a distance of more than 600 kilometers.

Open-File Report↗