Location of Mines

Bermudez Asphalt.

This is the name given to the asphalt obtained from a lake or deposit situated in the state of Bermudez, Venezuela. This deposit is said to have an area of over 1,000 acres.

It is situated about 60 miles from the coast, up the San Juan river. and about 51 miles distant from it. A narrow-gage steam railroad connects the deposit with the shipping point, so that vessels draw ing 18 feet of water can be loaded directly from the cars.

The crude asphalt is of the same variety as the Trinidad, namely. bitumen mixed with sand, clay, and vegetable matter. The aver age composition of the crude material is about as follows: The refining process is similar to that described for Trinidad asphalt (§ 590): but it is much more rapid, owing to the smaller amount of water and mineral matter present. In manufacturing asphaltic cement, the Bermudez asphalt requires much less of the fluxing agent than does the Trinidad on account of the large amount of oil contained in the former.

California Asphalt.

The aborigines of California used asphalt for making their canoes water-tight and for cementing their utensils and weapons; and the Spanish Mission fathers who first civilized the country used it for making floors, walks, reservoirs, and water conduits. The Mexicans who settled the country after the establishment of the missions also found many uses for the asphalt, and there are still to be seen numerous examples of their cisterns, pavements, walks, etc., in a good state of preservation. These uses were entirely local; and no steps were taken to extend the applications of asphalt until in 1884 some bituminous sandstone was shipped from Santa Cruz. In recent years the asphalt industry of the state has reached a considerable development; and at present California is the principal producer of asphalt in the United States. Probably this state not only has larger quantities of asphalt than any other equal area in the world, but has a greater variety of forms — solid and liquid asphalt, and asphaltic limestones and sandstones, — and in more localities.

Maltha ("fluid bitumen or liquid asphalt ") is found in small quantities in a number of places in the state, but the deposit of most commercial value is situated in Santa Barbara county, about 13 miles east of the city of Santa Barbara, on the shore of the Pacific Ocean. The deposit consists of a large body of bituminous sand covering an area of about 75 acres to a depth of 25 feet. The maltha is supposed to be supplied from a stratum of bituminous shale upon which the sand rests. The sand is covered with from 6 to 8 feet of surface loam which is washed off into the sea by a 12-inch stream of water under pressure supplied by steam pumps. A thin layer of clay resting directly upon the sand is next removed with spades. The sand is then loaded into cars with hot spades, and is drawn by a cable up an inclined way to the refinery, where it is dumped into a mixer consisting of a steam-jacketed cylinder in which re volving arms break up the lumps. The material then falls into vats of boiling water, the maltha floats, and the sand, sinking to the bottom, is carried away by mechanical means. The maltha flows from the surface of the water through a spout to a tank whence it is pumped into a storage tank at a higher elevation. From there it runs into refining kettles, where it is subjected for twenty-four hours to a heat which beginning at 100° F. is gradually raised to 240° F. This process removes all aqueous vapors and volatile oils,

and then the material is ready for use. The refined product con tains an average of 98.26 per cent of pure bitumen, and 1.74 per cent of mineral matter. This mine is the most extensive producer of natural fluid bitumen, or "liquid asphalt," in the world. This liquid is much used for fluxing the harder asphalts.

The most extensive deposit of solid asphalt in California is at La Patera, Santa Barbara county, 12 miles west of Santa Barbara immediately on the sea-shore. There are facilities for both rail and water transportation. The deposit covers an area of several hun dred acres, and the material is mined much as coal is. The supply, as in the case of the maltha, comes up from below, slowly but con tinuously. It is not soft, but is friable, and breaks readily under the pick. The sand is pulverized and conveyed to a large vat where the asphalt is dissolved out by gasoline. The gasoline overflows from the tank and runs down a pipe-line over a rough and sandy country 27 miles to the sea-shore, where it is distilled off and pumped back to the mine. The asphalt is put up in barrels for shipment. The average composition of the asphalt is as follows: Asphaltic limestone and sandstone are found at a number of places in California, in all degrees of richness and consistency. The principal deposits are at Santa Cruz, in Santa Cruz county, at San Luis Obispo, in the county of the same name, and at Kings City, in Monterey county. The asphalt is extracted from the stone by heating the mass in a tank and drawing off the liquid asphalt, which is shipped to various parts of this country to be used for paving pur poses.

The base of the California petroleums is asphaltic, as distinguished from the paraffin base of the eastern oils, and the process of refining petroleum leaves the asphalt or maltha as a residue, and at several places asphalt is produced from the crude petroleum.

Other American Asphalts.

Asphalt is found in quantities of considerable commercial importance in Utah, Colorado, Indian Territory, Texas, and Kentucky. For a detailed account of the geological occurrence of asphalt in these states, see an article by George H. Eldridge on Asphalt and Bituminous Rock Deposits in the United States, in Annual Report of U. S. Geological Survey for 1900-01, pages 219-464.

European Asphalts.

Asphalts from which pavements are made are found in Val de Travers, Canton of Neuchatel, Switzer land; Seyssel, Department of AM, France; Vorwohle and Limmer, Germany; and Ragusa, Sicily. The first two are the most im portant sources of supply. Although widely distributed, these asphalts are practically of the same nature, as shown by Table 41, page 397, and occur in strata varying in thickness from 6 to 23 feet. The rock is quarried, and then the blocks are crushed to the size of an egg by rollers provided with teeth and revolving at different speeds. These pieces are next reduced to a powder in a Carr disintegrator, and the powder is sifted to uniform fineness. It is then ready for use in making pavements. Large quantities of Trinidad asphalt (§ 590) are shipped to Europe and added to native asphaltic lime stones deficient in asphalt. On the other hand, asphalt is extracted from European asphalt rocks and shipped, usually in the form of cakes weighing 50 to 60 pounds, to this country to be used in mak ing artificial paving compounds.