A thorough examination of some of the iron ore properties and the knowledge acquired by development of extensive underground workings makes it possible to make quite definite estimates of tonnage available in certain areas, which show very large reserves. F. S. Witherbee in his paper read before the American Iron and Steel Institute last October gave an estimate of 1,100,000,000 tons of crude magnetic ore above 30 per cent. Fe available for concentration in the Adirondack region alone, not including any titaniferous ores except the one deposit at Lake Sanford. He practically confined his estimate to the area of the iron bearing gneisses which surround the central core of later eruptives, the anorthosites and gabbros, in which the titaniferous ores are found. There are also in New Jersey and southeastern New York large areas that give conclusive evidence of vast amounts of non titaniferous magnetites. The map accompanying the report of the State Geologist of New Jersey, year 1910, sh...
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Some time in the, year 1887 my attention was called to the magnetic separation of ores. At that time Edison was experimenting with his deflecting magnet and the Wenstrom, a Swedish machine of the drum type, was in use. The Conkling machine, which was also on the market, was the forerunner of the modern belt machine, but the magnetic attraction came from a single magnetized plate. My first experiment was with Port Henry old bed ore, which I crushed to pass through 1/8 in. mesh, and then ran through an old fashioned fanning mill, such as are used on farms. I had better results than those obtained by Mr. Edison with his deflecting magnet. I then made a trial of the Conkling idea but found that the magnetic plate picked up a large part of the gangue with the ore, so that the ore had to be sized and fed very slowly to get good results. The same trouble was experienced with the Wenstrom machine. I then made a small machine, substituting common horseshoe magnets , for the magnetic plate of...
The magnetic iron ores found in different localities vary widely, not only in their iron content, but also in their physical structure. The ores from the various districts require, consequently, radically different treatment. In the first place, bodies of ore differ widely in crystallography. For example, the ores of the Champlain Valley are more coarsely crystalline than the ores of New Jersey, the Benson mine, or the Cornwall ore bed. Obviously the mill treatment of these ores cannot be the same. Among other things, ore containing the coarser crystals would not require to be crushed to so fine a size as ore of the Cornwall type. It is very important to find the exact size at which any particular ore is most economically separated, and this size can easily be determined by experimental tests in a suitable laboratory. Moreover, the degree of fineness to which the ore must be crushed determines the process of separation to be employed. An ore which must be crushed to 1/8 in., 1/16 in...
The largest development in the iron ore industry, using magnetic concentration, is at the plants of Witherbee, Sherman Co. at Mineville, N. Y., where about 1,200,000 tons of crude ore were mined and separated in 1916. The dry process of separation is used. The Chateangay; Ore Iron Co., at Lyon Mountain, N. Y., the Empire Steel Iron Co. and the Ringwood Co. in New Jersey, also use the dry process successfully. The Grondal wet separators have been recently installed at the Benson mines in New York. The largest development of the, wet process in this country is on the Cornwall ore at Lebanon, Pa. This work is in charge of B. E. McKechnie, who is the highest authority on the wet process. In the practical application of magnetic separation the most vital part is the preparation of the ore. It must be crushed so that the crystals of magnetite, or groups of crystals, are sufficiently freed from rock to bring the percentage of iron up to the standard set for shipping ore. On the other...
During the dry magnetic separating tests on Cornwall ore, it became evident that this process of magnetic separation was not suitable for this ore, for the following reasons:
The following reports show results of samples tested to determine treatment required and quality of concentrates that could be expected. These tests were run on a regular mill size separator and the results could be duplicated in actual practice. The separate determinations of iron as magnetite, and total iron, were made so that the difference between the two would show the amount of iron combined as silicates in hornblende and other gangue minerals.
The known and partially developed orebodies of New York and New Jersey could, if equipped with the best modern mining and milling machinery and using the best methods, produce at the present time 25,000 tons of 60 per cent, iron ore per day. This can be delivered for an average freight charge of $0.75 per ton from mill to tidewater. The operating cost of production should reach the dollar rock ideal of the Lake Superior Copper region, and the cost of mining and milling 1 ton of crude ore should be about $1 for underground mining when handled in large quantities. The ratio of concentration would be 2 tons of crude per ton of concentrates for an average. There are reserves of magnetic ore sufficient to double the above production, and then last probably 100 years.
MAGNETIC SEPARATION PRINCIPLES AND APPLICATION IN BENEFICIATION OF IRON ORES A. Das and S. Roy INTRODUCTION Magnetic Separation is one of the physical concentration processes that utilizes the differences in magnetic properties of various minerals present in the ore body. The
Magnetic Separators for Mining Purposes offered to find use in protecting vital process equipment downstream from possible damages and provides for clean separated final processed product. These magnets find use in combination with hammer mills, primary jaw crushers, cone crushers and other tertiary crushers and support preventing damages to conveyor belts from possible damages like cutting, ripping or tearing from long sharp metal shards.
ADVANCES IN MAGNETIC SEPARATION OF ORES Magnetic separation of iron ores is one of the fastest growing segments of the minerah beneficiation industry. The tonnage of taconite ores processed annually by magnetic separation toill, in a few years, reach 100 million. by L. A. ROE M agnetic separation occupies an attractive posi
In iron ore beneficiation, LIMS are used to treat magnetite ore, while high intensity and high gradient magnetic separators are used to treat oxidized iron ores. Because different iron ores possess different magnetic characteristics, it is very important to develop an optimized flow sheet to maximize the Fe grade of the concentrate with high Fe recovery while at the same time minimizing operating costs.