LAVA, UNMANUFACTURED, NOT SUITABLE FOR MONUMENTAL OR BUILDING STONE (PAR. 1708) Comment This summary covers unmanufactured lava, except that suitable for use as monumental or building stone. 1/ Lava is a rock or mineral substance of volcanic origin, which varies greatly in composition and texture. It occurs either as rock formations which except for solidification have been little altered since being laid down, or as deposits which have undergone various stages of disintegration or transformation by natural forces. Lava, as mined, must usually be processed for commercial use. Its chief use is as crushed stone, i.e. for such purposes as concrete aggregate, roadbase metal, and railroad ballast. 2/ In addition to this use and as monumental and building stone, lava is also used for filtering acids, as an ingredient of cement, for making millstones, and, when vesicular in texture, for the construction of rolls and bedplates used in the preparation of wood pulp. 3/ Of the many deposits of lava throughout the world, only a relatively few are suitably located and have the proper qualities for commercial exploitation. Statistics on United States production of unmanufactured lava are not available; it is known, however, that the amount has been large for many years, and it is believed that annual production in the postwar period has exceeded that of prewar years. Because lava is used chiefly as crushed stone, domestic production depends largely on highway and other construction. United States production of lava is confined almost entirely to the Rocky Mountain States where volcanism took place on a large scale. Deposits of lava in that area are large and numerous, but many of them are not at locations accessible enough for commercial development. United States imports of lava, unmanufactured, have been negligible since the early 1920's, with the exception of the years 1937-39. Greece was by far the chief supplier of the small imports in 1937-39, accounting for virtually all of the 3,000 long tons, valued at $9,000 (foreign value), imported in 1937 and for all of the imports in 1938 amounting to 7,700 long tons, valued at $20,000. In 1939, however, Germany supplied practically all of the imports, which amounted to only 22 long tons, valued at $570. There were no imports of unmanufactured lave during the period, 1940-48. The average unit foreign value of the prewar imports of unmanufactured lava from Greece was about $3 per ton, which indicates that the Grecian material was used for purposes where texture was unimportant. Imports from Germany, having a foreign unit value of $26 per ton, probably consisted of lava to be used in making rolls and bedplates for pulp and paper machinery, for which use the vesicular texture of the German lava makes it particularly suitable. Statistics on United States exports of unmanufactured lava are not available, but exports are known to be negligible. 1/ Unmanufactured lava, suitable for use as monumental or building stone, is dutiable and is covered in the summary on sandstone, limestone, freestone, lava, and all other stone suitable for use as monumental or building stone, except marble, breccia, and onyx, unmanufactured, n.s.p.f., par. 234(c); these same stones, if hewn, dressed, or polished, or otherwise manufactured, are covered in a separate summary under the same paragraph. 2/ Crushed and ground lava are dutiable and are covered in the summary on stone, n.s.p.f., crushed or ground (except marble chip or granito and Cornwall stone), par. 214. 2/ Lava stones, processed for use as a component of pulp machinery, are dutiable and are covered in the summary on stock-treating parts for pulp and paper machinery, n.e. s. and knives and blades for meat machines, par. 356. SUMMARIES OF TARIFF INFORMATION LEECHES Tariff Status Par. 1709. Leeches, which were free of duty under the Tariff Act of 1922, are free of duty also under the Tariff Act of 1930. Trade Statistics Table 1.- Leeches: United States imports for consumption, Source: Note. Official statistics of the U. S. Department of Commerce. Statistics on leeches collected in the United States are not available. Exports, if any, are probably negligible. Comment Leeches of commercial importance are those used for medicinal purposes. They consist of three species of Hirudo, a genus of aquatic annelid worms: The gray or green leech (H. medicinalis), which inhabits marshes and running streams throughout Europe; the medicinal leech of America (H. decora); and the five-striped or Australian leech (H. australis). Leeches afford the least painful, and in many conditions, the most effective means for the local abstraction of blood. Although in former times local bloodletting was highly esteemed as a therapeutic measure, leeches are now very rarely employed. No statistics are available on the quantity or value of leeches collected either in the United States or in foreign countries. Imports into the United States are small (see table 1). In 1937-39, they averaged about $1,000 annually. During the war, imports increased, amounting to $3,236 in 1943, but declined thereafter, amounting to $135 in 1947. There were no imports in 1948. Italy and France were the only important prewar sources of United States imports of leeches; Portugal has been the sole source of imports since 1941. Exports of leeches from the United States, if any, are probably negligible. ASPHALTUM AND BITUMEN, NATURAL Tariff Status Par. 1710. Asphaltum and bitumen (other than petroleum asphalt), which were free of duty under the Tariff Act of 1922, are free of duty also under the Tariff Act of 1930. Their duty-free status was bound in the trade agreement with the United Kingdom, effective January 1939, and similar binding was thereafter included in the Geneva agreement. UNITED STATES TARIFF COMMISSION ASPHALTUM AND BITUMEN, NATURAL Trade Statistics Table 1.- Asphaltum and bitumen, natural: United States production, Includes 22,684 tons, valued at 588 thousand dollars, exported under lend-lease. 5/ Preliminary. 6/ Not available. 7 Less than $500. 8/ Computed on rounded value figures. |