Minerals of Commercial Importance

ANTIMONY

Composition.-Antimony is a metallic element.

It is usually found in its natural state as sulphide of antimony, or stibnite. It is also found as an impurity in other minerals, such as lead sulphide, silver, and bismuth.

Uses.-Metallic antimony is used principally in the manufacture of lead alloys, such as babbit and hard lead, solder, type metal, bullets, battery plates, Britannia metal, etc. It is also used in the manufacture of vulcanized rubber and rubber goods, enamel on metal ware, chemicals, paints, and pigments.

Occurrence. The antimony deposits of Arkansas occur in a rather narrow belt of steeply folded Mississippian shales and sandstones (Stanley Shale) in northern Sevier County, southern Polk and northwestern Howard Counties (see accompanying map). The stibnite deposits are associated with veins of quartz which penetrate the shales and sandstones and have somewhat northeast-southwest trends. The ore is associated with small amounts of copper, iron, zinc, and bismuth sulphides. These were probably deposited by the circulation of underground waters which dissolved the metals from deep-seated volcanic rocks and deposited them along veins a considerable distance above. The quantity of antimony ore in Arkansas has not been definitely estimated. A considerable amount of drilling would have to take place before an accurate estimate of the quantity of available ore could be made. The ore lies in lenses or pockets associated with quartzitic veins which are not continuous for any great distance. Some of the lenticular masses exceed 100 feet in vertical dimension and vary in width from three to forty feet, and vary in thickness from a feather-edge to two and one-half feet. The following are analyses of stibnite samples:

*U. S. Geological Survey Bulletin 340d, "Arkansas Antimony Deposits," by Frank L. Hess.

Mining is carried on by sinking shafts into the ore beds and drifting out from the main shaft. The shafts vary in depth from

20 feet to 220 feet.

Production. The production of antimony ore in Arkansas has gone on since about 1873, when antimony was discovered on the Otto property. Work was commenced that year in the Otto mine and has continued intermittently, depending largely on the market price of antimony. About 5,000 tons of ore have been removed since 1873.

There have been no State figures for the production of antimony since the severance tax law went into effect on April 23, 1923.

The available figures of the Arkansas production as given by the U. S. Geological Survey are as follows:

Following is a list of names of the mines which have numbers corresponding to those on the accompanying map, with approximate depth and probable tonnage, according to E. E. Vaughan of the Gilham Antimony Corporation.

Producers. Gilham Antimony Corporation, E. E. Vaughan, manager, Gilham, Arkansas.

1.

Bibliography of Antimony

1874

Williams, Charles P., "Notes on the Occurrence of Antimony in Arkansas."-Engineering and Mining Journal, Vol. 17, p. 386; 1874. Obtainable from McGraw-Hill Book Company, 10th Avenue at 36th Street, New York.

1877

2.

3.

4.

5.

Santos, J. R., "Analysis of Native Antimony Ochre from Sevier County, Arkansas."-Chemical News Vol. 36, p. 167.

1878

Dunnington, F. P., "The Minerals of a Deposit of Antimony in Sevier County, Arkansas."-American Association for the Advancement of Science, Tr. 26, pp. 181-185. Obtainable from American Association for the Advancement of Science, Smithsonian Bldg., Washington, D. C.

1907

Hess, F. L., "The Arkansas Antimony Deposits."-Bulletin 340d of the U. S. Geological Survey, "Rare Metals," pp. 241-252. Out of print at the present time, but may be consulted in public libraries.

1922

Mitchell and Graham, "Antimony in Southeast Arkansas."-Engineering and Mining Journal Press, Vol. 114, pp. 455-456. Obtainable from McGraw-Hill Book Company, 10th Avenue at 36th Street, New York City.

ASPHALT

Composition. Asphalt is a bituminous substance probably derived from organic matter sometimes found in porous beds such as sand, sandstone, or sandy limestone. In Arkansas there are seven known deposits of asphaltic sands, sandstones, and sandy limestones. They are located in Sevier and Pike counties along the northern edge of the Trinity formation of Lower Cretaceous age, as are shown on the accompanying map. This formation rests on the upturned edges of the Paleozoic (Mississippian) rocks. The origin of these deposits is not entirely known. It may be that they were once oil sands in the Trinity beds and eventually became asphaltic due to the volatilization of the more fluid portion of the petroleum on exposure to the atmosphere, or it is possible that the petroleum originated in the Mississippian beds and saturated the Trinity sands above them. These sands were later eroded and the lighter portions of the petroleum volatilized. The following is an analysis of five of the Arkansas asphalt sands:*

Occurrence. The asphalt deposit two and one-half miles southeast of Pike in Pike County was worked from 1900 to 1906. During those years the Arkansas Asphalt Company mined 4,815 tons valued at $22,368. This was used in Little Rock to pave twelve blocks on West Markham from Main to Cross Streets and also a part of Center Street. Owing to the fact that the asphaltic sand did not receive entirely proper treatment, some of the pavement which was made from it did not prove satisfactory. Some of the asphalt is suitable for laying cold, while some needs to have bitumen added in order to make it suitable for paving. It is possible that, due to the fact that the shipment of the lime and sand is a considerable item of expense, the deposits can best be worked by extracting the bitumen and shipping it to the point where it is expected to be used,

*C. W. Hayes, The Asphalt Deposits of Pike County, Arkansas."-Engineering and Mining Journal.

and mixing it with locally secured sand and ground limestone at such points.

A deposit of asphaltic dolomite has been found in southwestern Scott County at the northern base of Fourche Mountain. This deposit occurs in the Jackfork sandstone of Mississippian age. There has been no development of this deposit.

None of the asphaltic sand deposits in the State are now being developed.

At the present time nearly, if not all, of the asphalt used in Arkansas is derived from crude oil residues.

1.

2.

3.

Bibliography of Asphalt in Arkansas

1902

Hayes, C. W., "Asphalt Deposits of Pike County, Arkansas."-U. S. Geological Survey Bulletin No. 213, pp. 353-355. Now out of print, but may be consulted in public or scientific libraries.

Hayes, C. W., "The Asphalt Deposits of Pike County, Arkansas."-Engineering and Mining Journal, 74:782. Obtainable from Engineering and Mining Journal Press, Tenth Avenue at 36th Street, New York.

1918

Miser, H. D., and Purdue, A. H., "Asphalt Deposits and Oil Conditions in Southwestern Arkansas."-U. S. Geological Survey, Bulletin No. 691j, pp. 271-292. Now out of print, but may be consulted in public or scientific libraries.