Ranges of demand projections to the year 2000. 

 Area Projection base 1970 1985 2000 



Prospective supplies and prices. Thorium is a by-product of the processing of monazite for the 

 rare-earth elements, the large production of which creates an excess supply of thorium. Much of the 

 monazite is imported from Australia and Malaysia. Thorite and thorianite are also sources of thorium. 

 Both domestic and world reserves of thorium are very large and projected nonenergy needs to the year 

 2000 would scarcely make a dent in them. The price of thorium, in this case, should remain fairly 

 steady. 



Nuclear uses for thorium are in the experimental and developmental stages. The Peach Bottom, 

 Pennsylvania and Elk River, Minnesota reactors are prototype nuclear power plants using thorium as part 

 of the nuclear fuel. The development of an economic thorium converter or breeder reactor would create 

 a large demand. Because such a development is unpredictable in timing and in competitive worth against 

 uranium, no estimates of thorium demand for this purpose can be of value at this time. Even for such a 

 large demand, reserves are ample to carry beyond the year 2000. 



Possible substitute materials. No satisfactory alternate materials are suitable for the larger nonenergy 

 uses of thorium, particularly in gas mantles and in alloys. Zirconium and titanium are superior to 

 thorium as a getter in electronic tubes. Beryllia and yttria can substitute as a refractory above 2000°C. 

 Uranium breeder reactors are competitive to a certain extent with thorium breeder reactors but neither 

 has been sufficiently developed to predict which will find greatest use. 



Potential from marine sources.'^^ Monazite, a rare earth phosphatic mineral containing up to 12 per 

 cent ThOj , is the major source of the world's thorium. It is a fairly common accessory mineral in 

 granitic rocks but is generally far too dilute in these rocks to be minable. Fortunately monazite's high 

 density and resistance to chemical weathering favors its concentration in alluvial and beach sands. 



Between 1895 and 1965 quantities of monazite have been recovered from modern and raised beaches 

 in Florida and South Carolina, and minor quantities have been mined from beaches and alluvial placers 

 in North Carolina, Georgia, and Gulf Coast States.* ^ 



An estimate of total monazite production between 1895 and 1962 from southeastern States' beach 

 and alluvial deposits is 4,000 to 10,000 tons. Unfortunately, the ThOj content of these monazites 

 averaged only 3% to 4 per cent. Since the 1920's recovery of monazite has been limited to by-product 

 operations principally concerned with the mining of rutile, ilmenite, and zircon. This was terminated in 

 1965 when black sand deposits were exhausted." ' 



The monazite placers in the southeastern States are richest near the headwaters of streams, closest to 

 source rocks as might be expected. Closer to the sea the deposits are more widespread but the grade 



Summaiized largely from Ocean Science and Engineering, Inc. report. 



"^^J. C. Olson and K. C. Overstreet, "Geologic Distribution and Resources ofThorium," Geological Survey Bull. No. 

 1204, 1964. 



'^''c.T.Baioch,'"Thon\xm,"mMmeral Facts and Problems, Bureau of Mines Bull. No. 630, 1965. 



VII-157 



