Phosphate mining

Cost Fa.ctors, The dehvered costs of the phosphate rock and sulfuric acid raw materials often account for more than 90% of the cost of producing NSP, thus the production cost varies considerably with plant location. Because the rock is richer in P2O5 than is the low analysis NSP product, NSP need not be produced near the phosphate mine. However, deUvery of sulfuric acid and shipment of product to market are important cost factors. Most United States NSP plants have been located east of the Mississippi river, with concentration in the southeastern and extreme southern parts of the country where the largest use of the product has occurred. Production and use of the product also has been high in California. 

Occasionally, the phosphate slime is difficult to settle in the lagoons because of its true colloidal nature, and the use of calcium sulfate or other electrolytes can promote coagulation, agglomeration, and settling of the particles. Usually an addition of calcium sulfate is unnecessary, because it is present in the wastewater from the sand-flotation process. Generally, it has been shown [33] that the clear effluent from the phosphate mining and beneficiation operation is not deleterious to fish life, but the occurrence of a dam break may result in adverse effects [19]. 

IIAP (Cas(POj),OH). FAP (Ca (P04hF). Carbonate FAP iCa,0uP04isCOjlOH.Fj. Florida is a mined naiural apatile mixiure of FAP and HAP (IMC Agrico. Mulberry. FL). North Carolina is mined natural Carbonate FAP (Aurora Phosphate Mine. Lee. NC). Bone char is apaiile made from bone char. Apuliic II is an FAP and HAP mixture made from fish bones. 

Many shallow deposits have unconsolidated ore covered by unconsolidated overburden. Large electric walking draglines are ideally suited for such deposits, as evidenced by their use at large capacity phosphate mines in the southeastern United States, Morocco, Jordan,... 

Bucketwheel excavators are used for overburden removal at phosphate mines in eastern North Carolina, Senegal, and Togo. One mine in central Florida has used cutter head dredges for both overburden removal and ore excavation. 

The initial beneficiation steps for consolidated phosphate ores generally differ from those of unconsolidated ores. Figure 23.6 depicts the flow diagram for the San Juan de la Costa phosphate mine in Mexico. 

Uranium releases occur as a result of phosphate mining for production of phosphorous, which is used in phosphoric acid and phosphate fertilizers (NCRP 1984a). Phosphate rock from Florida, Texas, and southeastern Idaho contains as much as 120 ppm (80 pCi/g) uranium, a concentration sufficiently high to be considered as a commercial source of uranium (NCRP 1975). 

Fitzgerald, J.E. and Sensitaffar, E.L., Radiation exposure from construction materials utilizing by-product gypsum from phosphate mining. In Mogihissi et al. (eds.). Radioactivity in consumer products, pp. 351-368. Report NUREG/CP-OOOl. Washington Nucl. Reg. Commission, 1978. 

Roessler, C.E., Control of radium in phosphate mining, benefication and chemical processing. In IAEA. The Environmental Behavior of Radium, pp. 269-279. Technical Reports series no. 310. IAEA, Vienna, 1990. 

Zellars-Williams, Inc., "Water Recirculation System Balance of Central Florida Phosphate Mining. Mine I Calculations. 1974-1975 Rainfall Calculations." BuMines Open File Report No. 120-77. Tuscaloosa. AL. 1977. p, IV. 

The third objective was to determine if radium was being leached. Background concentrations of radium in many materials present in the phosphate mining area... 

In general, radium in rock does not pose a health risk, but there are situations where radium is found in unusual abundance, and care must be taken with human exposure. Oil fields, coal mines, and phosphate mines generate hazardously high concentrations of radium as uranium and thorium deposits are disturbed underground. In Poland, for example, radium-containing water that was discharged from coal mines has been... 

Human activities affect the global phosphorus cycle to an ever-increasing degree. The late of phosphate mining equals or exceeds the rate of phosphate lost naturally from the continents. About 35 x 1010 mol yr-1 are used as phosphate fertilizer, while 6 x 1010 mol yr-1 are used by other industries and in the home. The industrial forms are particularly soluble, so the phosphate in sewer discharge, as well as the lesser-available forms from farm runoff and erosion, is already affecting freshwater and marine ecology in North America, Europe, and Asia. 

The unique settings in which phosphorites form, those areas where phosphate is concentrated millions of times above normal and sedimentation rates are drastically slowed, are not fully understood, and have been the subject of sometimes intense scientific debate over the last century and a half Furthermore, the mineralogy of these deposits is unique, difficult to study, and contentious. Because of our dependence on phosphate for use in fertilizers and other agricultural and chemical uses, these deposits are interesting not only from a scientific viewpoint but from an economic standpoint as well. However, like many mining operations, phosphate mining has environmental problems that must be addressed. 

Figure 4. Location map showing the four active phosphate mines in southeastern Idaho. Less-weathered and more-weathered sections were collected at the Enoch Valley, Dry Valley, and Smoky Canyon mines. A deep, least-weathered section was collected at the Enoch Valley mine (modified form Herring et al. 1999).

Like many mining and refining operations there have been environmental concerns surrounding phosphate mining in Idaho. Until recently the most significant problems had been the air quality of calciner emissions, water quality surrounding waste piles, slight... 

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