Economic Geology, Količina 1Economic Geology Publishing Company, 1906 |
Iz vsebine knjige
Zadetki 1–5 od 61
Stran 16
... crystals . The Butte covellite is one of the secondary products from the changes in cupriferous pyrite and it is of great interest to find the chalco pyrite formed so late in the process . Chalcopyrite occurs so often in association ...
... crystals . The Butte covellite is one of the secondary products from the changes in cupriferous pyrite and it is of great interest to find the chalco pyrite formed so late in the process . Chalcopyrite occurs so often in association ...
Stran 19
... crystals , it is almost always massive or in black crusts or pulverulent coats , which , as W. H. Weed has shown in the case of Ducktown , have sometimes been taken for melaconite , the black oxide . So far as observed and interpreted ...
... crystals , it is almost always massive or in black crusts or pulverulent coats , which , as W. H. Weed has shown in the case of Ducktown , have sometimes been taken for melaconite , the black oxide . So far as observed and interpreted ...
Stran 47
... Crystal Falls district the iron- formation is in both Upper Huronian and Lower Huronian series , the former being the principal producer . In the Meno- minee district the formation is of Upper Huronian age . The iron - formations of the ...
... Crystal Falls district the iron- formation is in both Upper Huronian and Lower Huronian series , the former being the principal producer . In the Meno- minee district the formation is of Upper Huronian age . The iron - formations of the ...
Stran 48
... Crystal Falls dis- tricts , the original rock has been described as iron carbonate . In the Mesabi district , the original rock has been described as con- sisting of ferrous silicate or " greenalite " granules principally , but with ...
... Crystal Falls dis- tricts , the original rock has been described as iron carbonate . In the Mesabi district , the original rock has been described as con- sisting of ferrous silicate or " greenalite " granules principally , but with ...
Stran 49
... Crystal Falls districts . So far as the re - examination has gone , however , it tends to confirm the essential correctness of the determination of iron carbonate as the dominant original iron - formation rock for these districts . In ...
... Crystal Falls districts . So far as the re - examination has gone , however , it tends to confirm the essential correctness of the determination of iron carbonate as the dominant original iron - formation rock for these districts . In ...
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Druge izdaje - Prikaži vse
Pogosti izrazi in povedi
acid altered amount andesite basin beds bornite Bull calcite cent chalcocite chalcopyrite chemical chert chloride clay coal conglomerate contain copper country rock Creek Cretaceous crystals deposits depth dikes economic geology epidote eruptive faults feet feldspar field fissure vein formation fractures galena Geological geologist gold granite hematite Hill igneous rocks important intrusive investigation iron-formation Lake Superior later less lignite limestone lodes magma magnetite masses material metals metamorphism microscope miles mineral mining districts muscovite nickel occur origin outcrop oxide paper phases planes plates portion present probably production pyrite pyrrhotite quartz quartz veins region rhyolite sandstone schists scientific secondary sedimentary sediments sericite shale siderite silicates silver smaltite solution specimens structure sulphate sulphides sulphur surface syncline temperature thickness tion U. S. Geol U. S. Geological Survey United States Geological vertical volcanic zinc zone
Priljubljeni odlomki
Stran 573 - States governing their possessory title, shall have the exclusive right of possession and enjoyment of all the surface included within the lines of their locations, and of all veins, lodes, and ledges throughout their entire depth, the top or apex of which lies inside of such surface lines extended downward vertically, although such veins, lodes, or ledges may so far depart from a perpendicular in their course downward as to extend outside the vertical side lines of such surface locations.
Stran 573 - But their right of possession to such outside parts of such veins or ledges shall be confined to such portions thereof as lie between vertical planes drawn downward as above described through the end lines of their locations, so continued in their own direction that such planes will intersect such exterior parts of such veins or ledges.
Stran 258 - Engineer, being the art of directing the great sources of power in Nature for the use and convenience of man...
Stran 573 - ... throughout their entire depth, the top or apex of which lies inside of such surface lines extended downward vertically, although such veins, lodes, or ledges may so far depart from a perpendicular in their course downward as to extend outside the vertical side lines of such surface locations. But their right of possession to such outside parts of such veins or ledges...
Stran x - Particular attention given to the work of Schools, Colleges, Universities and Public Institutions Books, Periodicals Technical and Scientific Publications Monographs, Theses, Catalogues Announcements, Reports, etc. All Kinds of Commercial Work Publishers will find our product ranking with the best in workmanship and material, at satisfactory prices.
Stran 56 - But detailed study shows that other factors modify the circulation of water and the localization of the ore and that these secondary factors may be locally dominant. The most important of these modifying factors is the fracturing of the iron formation which has furnished numerous trunk channels for the circulation of underground waters. The water has been confined to narrow, irregular, and most devious trunk channels formed by the fracturing of the iron formation, and, while it has probably followed...
Stran 575 - Where two or more veins intersect or cross each other, priority of title shall govern, and such prior location shall be entitled to all ore or mineral contained within the space of intersection...
Stran 57 - ... areas. Other factors modifying the general underground flow of water in the Mesabi iron formation are the numerous impervious slaty layers within the iron formation and the Virginia slate capping the iron formation of the south, all of which have considerable effect in directing water circulation. So far as the water is free to flow southward through the iron formation the impervious layers serve only to limit the flow below. But the continuous south dip of the impervious strata carries the waters...
Stran 745 - The faults, formed subsequent to the original period of vein deposition, may have determined the position of the bonanzas formed during a period of secondary enrichment of the vein, either by acting as barriers to migrating auriferous solutions, or by forming channels along which solutions came, reacting with those in the original vein channel. The great Waihi Mine, which is now working on the complex system of branching reefs — the Martha, Welcome, Empire, Royal and several smaller veins — had...
Stran 4 - By this correction of his first opinion, a new approximation is made to the truth; and by the repetition of the same process certainty is finally obtained. Thus theory and observation mutually assist one another; and the spirit of system, against which there are so many and such just complaints, appears, nevertheless, as the animating principle of inductive investigation. The business of sound philosophy is not to extinguish this spirit, but to restrain and direct its efforts.