High-grade Clays of the Eastern United States: With Notes on Some Western ClaysU.S. Government Printing Office, 1922 - 314 Seiten |
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_do____ 50 feet abundant Air shrinkage ball clay beds borings cent in terms clay deposits color cone contains County Creek Cretaceous crucibles crude clay crude kaolin decomposed deposits of kaolin depth diaspore dike Dillsboro domestic clays dry clay English clay feet wide feldspar feldspathic Ferric oxide Fire tests flakes flint clay formation Geol Geological grains granite Harris Kaolin hydromica indianaite kaolin deposits kaolinite lignite limonite linear manufacture mass material mica microscope miles mineral Mines Mitchell County mixture Modulus of rupture Mount Holly Springs Mountain North Carolina occur overburden oxide pegmatite Penland physical tests Porosity Porosity per cent quantity quartz quartzite residual clay rock rutile sagger sample sand sandstone Saylorsburg schist sedimentary clays shaft shows shrinkage per cent sieve Silica Sprucepine stained Steel hard streaks Temperature Tenn Tennessee terms of dry tests of clay tons tourmaline tunnel Volume shrinkage wall washed kaolin Water of plasticity white clay
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Seite 15 - Their thickness ranges from a fraction of an inch up to 6 or more feet. Many of them are lenticular in shape, the length varying from four or five to twenty or more times the thickness. ' In numerous places these quartz streaks or veins are persistent through the whole length of the pegmatite exposed. Some inclose feldspar or mica bodies; others do not. The quartz of these segregations is massive and generally granular, though locally crystallized. If crystallized it may be translucent or clear and...
Seite 15 - The mica occupies various positions in the pegmatite. Where the rock has a typical granitic texture, the mica may be found evenly distributed through it. More commonly the larger crystals will be found either in clusters at intervals through the "vein," in places connected by streaks of small crystals, or collected along one or both walls of the pegmatite, with some of the crystals partly embedded in the wall rock. Where there is a quartz streak within the pegmatite, the mica occurs on either or...
Seite 49 - ... at one point a considerable quantity of fine white kaolin is encountered. There are, however, occasional streaks of fresh feldspar and on all sides of the lens there is semi-kaolinized material; these facts justify the assumption that the kaolin is merely an isolated lens and would not justify the equipment of an extensive outfit for handling it, although the presence in the neighborhood of other isolated kaolin deposits would justify the sinking of shafts and the removal of this kaolin to a...
Seite 15 - Generally, however, they occur in bands or sheets lying parallel to the walls. There may be one or more of these quartz bands constituting varying proportions of the pegmatite. Their thickness ranges from a fraction of an inch up to 6 or more feet. Many of them are lenticular in shape, the length varying from four or five to twenty or more times the thickness. In numerous places these quartz streaks or veins are persistent through the whole length of the pegmatite exposed. Some inclose feldspar or...
Seite 36 - ... referred to above as having been explored by borings that cover about four and two-thirds acres. The borings are in lines running northeast and northwest and at intervals of about 50 feet. The overburden averages in thickness not more than seven or eight feet and the depth of the clay penetrated varies from 20 to 45 feet. On the assumption that the average thickness of the clay is 30 feet and that the average yield of commercial kaolin is about 20 per cent of the crude tonnage the productive...
Seite 57 - The property is undeveloped, but cuts on the railway and on the highway one-fourth mile west of the railroad expose a white kaolin. On the east side of the railroad right-of-way a section of about 160 feet is exposed and between this and the track are a couple of shallow pits. The section is in alternating schists and kaolin. At its north end a width of 20 feet of kaolin is shown, followed to the south by 20 feet of quartz, 110 feet of kaolin and finally schists. (See Fig.
Seite 7 - ... belts of kaolin that result from the decomposition of pegmatite dikes. Where feldspathic granites or other feldspathic rocks occur over large areas these may give rise to deposits of kaolin (the "blanket deposits" of Ries) that are so large, that by their very massiveness they may reveal themselves on the surface. Because of its striking appearance, the kaolin, even when much mixed with other materials, may be recognized, and, because it may migrate down slopes, in many cases it may appear to...
Seite 139 - ... small white granules of clay, producing an amygdaloidal structure. These small granules have about the same degree of hardness as the surrounding kaolin. Under the microscope the porcelain-like kaolin exhibits a granular appearance, the grains being apparently spherical in form and in some sections arranged in a dendritic structure. The dendritic structure may be due to the loss of water and consequent shrinkage when the section is heated during its preparation. In some places the white kaolin...
Seite 145 - ... chemistry of the clay and hematite deposit, for, though similar in its chemical composition to kaolin, this clay differs physically and owes its origin to an entirely distinct set of causes and effects. While the former is derived from the decomposition of the feldspar of feldspathic rocks, such as granite, porphyry, etc., the porcelain clay of Lawrence county has resulted from the decomposition, by chemical waters, of a bed of limestone and the mutual interchange of molecules in the solution,...