Production and consumption of crude feldspar in the United States increased in 1971 and more than compensated for the 1970 decline, climbing to within 2 percent of the alltime record tonnage of 1969. The total value of the 1971 output was the highest on record, 3 percent more than the 1970 figure and almost 50 percent above the annual average of the previous decade. These feldspar statistics, together with those showing U.S. consumption in 1971 of aplite and Canadian nepheline syenite in record or near-record quantities, attested to the solid prosperity of the containerglass industry, which provides by far the largest domestic market for these feldspathic materials. The dimensions of this industry can be visualized by noting that the year's total of glass-container shipments

came to 38 billion units-equivalent in volume to the Great Pyramid of Cheops 20 times over.

Events in 1971 indicated that the throw-away bottle is probably here to stay but that a better means needs to be devised for channeling the discarded glass into recycling or alternative-utilization schemes that have the potential of being profitable. Achievement of that end would be beneficial to the producers of feldspathic materials, to the manufacturers of glass containers, and to the general public. Intensive research sponsored by private organizations and Government agencies is now being directed toward that goal.

1 Physical scientist, Division of Nonmetallic Minerals.

DOMESTIC PRODUCTION

Crude Feldspar.-North Carolina has held first place as a domestic source of crude feldspar since 1916, and the industry's production facilities in that State have been expanded notably in recent years. In 1971, International Minerals & Chemical Corp. placed in operation completely new and modern feldspar flotation plant near Spruce Pine, adding substantially to that firm's production capacity. Also near Spruce Pine, Lawson-United Feldspar and Mineral Co. brought near to completion a program initiated in 1968 for major expansion and modernization of the Minpro feldspar processing plant. Feldspar was mined in 1971 in 10 States, eight of which reported production increases. These increases compensated for declines in two other States (as well as for Maine's withdrawal from the list of feldspar producers, the first such absence for that State in 77 years), and carried the year's production beyond that of 1970 by 2 percent in quantity and 3 percent in total value. North Carolina, California, Connecticut, and South Carolina (in order of output) jointly accounted for 88 percent of the 1971 tonnage and 86 percent of the total value; Georgia, South Dakota, Virginia, Wyoming, Arizona, and Colorado supplied the remainder.

Leading feldspar producers were The Feldspar Corp., with mines in Mitchell County, N.C., Middlesex County, Conn., and Jasper County, Ga.; International

Minerals & Chemical Corp., with mines in Mitchell County, N.C., Custer County, S. Dak., and Mohave County, Ariz.; and Wedron Silica Co. in Monterey County, Calif.

In 1971, 6 percent of the total tonnage of crude felspar sold or used by producers in the United States was hand-cobbed material, 60 percent was flotation concentrate, and 34 percent was feldspar in feldspar-silica mixtures. As indicative of trends, the corresponding figures for 1966 were 18 percent, 62 percent, and 20 percent, respectively; for 1961, the figures were 23 percent, 62 percent, and 15 respectively.

percent,

Ground Feldspar. For glass-furnace feed, feldspar customarily is ground no finer than 20 mesh; feldspar to be used for ceramics and filler applications is pulverized to minus 200 mesh or finer. Seven companies, operating 13 plants in seven States, ground feldspar for market in 1971, supplying ground material (7 percent less in total tonnage than in 1970) for shipment to destinations in 30 States and four foreign countries. Listed in order of output tonnages, North Carolina had six grinding mills, Connecticut had one, and California had two; these were the leaders in ground feldspar production and jointly supplied 78 percent of the 1971 total. Following in order, South Carolina, Georgia, South Dakota, and Arizona were the four States that made up the remaining 22 per

cent.

8,715,643

CONSUMPTION AND USES

Crude Feldspar.-In 1971, as usual, little or no feldspar was consumed as the unprocessed mine product; the majority of users received their supplies of the mineral already ground and sized either by the primary producers or by merchant grinders. Some manufacturers of pottery, soaps, and enamels, however, purchased comparatively small quantities of crude feldspar for grinding to their preferred specifications in their own mills.

Ground Feldspar.-The 1971 pattern of ground feldspar consumption in the United States was similar to that of the previous year, but the confidential status of some of the 1971 data precludes direct comparison. The 1971 end-use distribution, insofar as publishable, showed that 51 percent of the total was consumed for glassmaking. and 49 percent for pottery,

enamel and miscellaneous uses, combined; compared with 1970 data, which showed 55 percent for glass, 36 percent for

pottery, and 9 percent for enamel, and other uses. The comparable averages of the annual end-use figures for the decade of the 1960's showed that 55 percent of the total was used for glass, 30 percent for pottery, 4 percent for enamel, and 11 percent for other purposes.

These data suggest a trend toward relatively greater consumption of feldspar for pottery and less for enamel. The proportion of feldspar consumption allotted to glass manufacture has remained comparatively stable since the early 1950's, even though the container-glass industry has expanded spectacularly in the interim (shipments of glass containers in 1970 were up from 1950 by a factor of 212). It seems that the static position of glass-grade feldspar in the consumption pattern is a reflection of the increasing utilization of imported nepheline syenite (51⁄2 times more in 1970 than in 1950), most of which serves, at the expense of feldspar, as a feldspathic material for glassmaking.

Exports from the United States in 1971 included 3,557 long tons of material indeterminately classified by the Bureau of the Census as feldspar, leucite, nepheline, or nepheline syenite (but presumably all or mostly feldspar) with a total value of $141,234, 28 percent below comparable figures for 1970.

Feldspar imports in 1971 were at the lowest level since 1965 in tonnage and since 1961 in total value. Conforming to the usual pattern, 1971 imports of feldspar were more than balanced by corresponding exports, but both of these items were of minor significance compared with imports of Canadian nepheline syenite. U.S. imports in 1971, in addition to materials specifically listed in the feldspathic category, included 4,297 long tons of material valued at $376,391 that was classified as "natural mineral fluxes, crushed, ground, or pulverized."

The appropriate tariff schedule called for a duty of 2 cents per long ton on crude feldspar and of 4 percent ad valorem on ground feldspar during 1971 (down from 5 cents per long ton and 5 percent ad valorem, respectively, in 1970).