Upper Silesian Coal Field

in Poland and Czechoslovakia. The area of the Polish part is about 4,500 sq km. The southern portion is in Czechoslovakia and bears the name Ostrava-Karviná Basin (area 950 sq km). In coal output (128.6 million tons in 1968 in Poland and 25.9 million tons in Czechoslovakia) and in geological reserves (94.6 billion tons to a depth of 1,000 m; including balancing reserves of 30 billion tons), it is one of the largest in Europe. The field consists of a large hollow; in the northern portions and in some places in the western portions coal-bearing deposits of the Carboniferous period emerge on the surface; in the central and southern portions they descend to a depth of over 1,000 m and are unconformably covered over with Mesozoic and Cenozoic deposits.

The industrial coal-bearing portion has a total thickness of 4-5 km and is composed of sandstones, shales, limestones, and seams of coal; it is divided into three series: the Ostrava series and saddle series of the Namurian stage and the trough series of the Westphalian stage. Each of them is subdivided into several suites. As a result of repeatedly occurring manifestations of volcanism in post-Carboniferous times, intrusions, veins, and covers of basalts, porphyrites, and melaphyres were intruded into the coal-bearing deposits. The northwestern portion is distinguished by a more complex tectonic structure: numerous folds are broken by faults; a broad band of similar faults goes through the northern portion of the central region, where a series of stepwise faults with an amplitude of almost 200 m has developed.

In degree of coal-bearing capacity, the Upper Silesian coal field is numbered among the richest. It has over 450 beds and seams of coal; of these, 98 beds in the western portion are of workable thickness; in the eastern portion such beds are fewer. The usual thickness of the beds is 1.5-2.0 m, but a few attain a thickness of 7-9 m and even 24 m.

There is a complete range of grades of coal—from long-flame coal through poor; for the most part it is classified as high-quality coal having a low content of moisture, ash, and (for the majority of beds) sulfur and giving good metallurgical coke.