Economic geology

Front Cover
 

What people are saying - Write a review

We haven't found any reviews in the usual places.

Other editions - View all

Common terms and phrases

Popular passages

Page 54 - The exports consist both of anthracite and bituminous coal, the amount of bituminous being the greater in the last few years. They are made principally by rail over the international bridges and by lake and sea to the Canadian provinces. Exports are also made by sea to the West Indies, to Central and South America, and elsewhere. The imports are principally from Australia and British Columbia to San Francisco, from Great Britain to the Atlantic and Pacific coasts, and from Nova Scotia to Atlantic...
Page 770 - Ores containing less than 40 per cent manganese or more than 12 per cent silica or 0.225 per cent phosphorus are subject to acceptance or refusal at the buyer's option. Settlements are based on analysis of sample dried at 212 F., the percentage of moisture in the sample as taken being deducted from the weight.
Page 472 - Fnhlband is a term originally used by German miners to indicate certain bands of schistose rocks impregnated with finely divided sulphides, but not always rich enough to work.
Page 87 - It is, of course, necessary that the oil-bearing stratum shall be capped by a practically impervious one. If the rocks are dry, then the chief points of accumulation of the oil will be at or near the bottom of the syncline, or lowest portion of the porous bed. If the rocks are partially saturated with water, then the oil accumulates at the upper level of saturation.
Page 802 - ... subjected. This left them in the right physical condition to be readily jointed and fissured by the contraction of the diabase. After the deposition of the cobalt-nickel arsenides, which seem to be among the first minerals deposited, the veins appear to have been slightly disturbed, giving rise to cracks and openings in which the silver and later minerals were deposited. Veins which escaped this later, slight disturbance contain little or no silver.
Page 564 - ... iron content of the ore used, involving a corresponding increase in cost of transportation per unit of iron, there will be an increase in the proportion of fuel which goes to the region producing the ore. This will be accompanied by the general adoption of by-product coking. It is an instructive fact that in certain furnaces now operating in the Lake Superior district the profit corresponds approximately to the value of the by-products from the coke ovens. In making estimates all of these considerations,...
Page 276 - ... thickness, separated by thin beds of limestone or shale, in the series. Usually one and sometimes two of these beds at a given section are workable, and probably some of the others will eventually be mined. The lime phosphate content in the workable beds varies from 65 to 80 per cent, with an average of 72 per cent.
Page 52 - ... DISCOVERY. Though La Salle in his hypothecated descent from the headwaters of the Allegheny to the Falls of the Ohio in 1669-703 would have passed by the eastern Kentucky coal field, he left no record indicating that he found coal during these explorations. To Father Hennepin,4 a French Jesuit Missionary, who in 1679 recorded the site of a "cole mine...
Page 329 - ... minerals and the common phenomena of marked silicification of the hanging wall are interpreted as indicating deposition from heated ascending solutions carrying fluosilicates of zinc, lead, copper, iron, barium, and calcium. These are believed to have been broken up and precipitated by descending cold waters, which possibly also furnished the sulphur to combine with the metals, though it is not improbable that sulphur was an original constituent of the rising solutions.
Page 287 - Fig. 2), the raw material quarried for scythestones is a fine-grained, thinly laminated, micaceous sandstone, whose quartz grains occur in definite layers, separated by thin layers of mica flakes.

Bibliographic information