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By Bernard MacDonald

Introduction. OF the treatment of the slime-pulp of gold- and silver-ores by cyanidation, agitation is an essential part. When prepared for treatment, this pulp, consisting of ore reduced to such fineness that approximately 80 per cent. of it will pass through a 200-mesh screen, is mixed with a certain proportion of water, carrying in solution the quantity of cyanide (KCN) and other chemicals required. The water-constituent of the pulp thus prepared usually ranges from 1 to 2 parts by weight to 1 of the dry ore. Thus constituted', the pulp is charged into treatment-tanks, the shape and capacity of which vary, according to the quantity of pulp to be treated daily and the method of agitation to be employed. Tanks have no other function in a cyanide-plant than that of being economical and convenient containers or receptacles for holding the pulp, solution, or water used in the operations. It is by agitation that the solids in the pulp charged into the tanks are kept in suspension in, and mixed with, the solution in the proper proportions required for the treatment. If the proper mixture of solution to solids be determined to be 2 to 1 by weight (which is, approximately, 5 to 1 by volume), this proportion should be maintained in every part of the charge ; -that is, each solid particle of the pulp, whether it be of 180- or 400-mesh size, should, be surrounded by five times its own volume of solution throughout the whole period of treatment. The reason is, that the amount of chemicals ascertained to be necessary for dissolving the gold and silver contained in the solids, is held in uniform solution in the water-constituent of the pulp, and, therefore, the determined proportions of solution and solids must be maintained at all times during treat-

Apr 1, 1912

By R. E., Head

THE use of lime in flotation has become so general in recent years that its functions are familiar to plant operators. The conditions and phenomena described in this paper are of interest because they are directly associated with the use of lime as a reagent and the resulting formation of lime scale worth nearly $1 per pound for its gold content. It is not known to what extent lime scale is common in flotation plants where lime is used, but as several occurrences have been re- ported, its existence is not limited to one particular plant. In November, 1927, the author's attention was drawn to a lime scale that formed on the sides of Callow flotation cells in the Walker Mining Co. mill at Spring Gar- den, Cal. The scale was described as an accumulation of hard material that built up on the sides of both the rougher and cleaner cells and in some instances attained a thickness of 2 in. The lime scale builds up in the cleaner cell at the rate of about 1/10 in. per month, or slightly more than ?12 in. during six months' operation. The rate of growth in the rougher cells is slower, and about 3/s in. of scale forms in six months. Analyses' of typical lime scale samples are as follows:

Jan 1, 1928

By John P. Cosgro

THE increasing use of internal furnace-boilers for mining power-plants (doubtless due to the facility with which they may be installed by reason of their portability; the fact that they require no masonry setting, cast-iron fronts, buck-stays, etc., and practically no foundation; and the successful maintenance of their claim to equal and even superior economy, as compared with boilers of other types) warrants this description of a method of remedying an injury which may occur, to such a furnace, even though it satisfies the requirements of the formula adopted by the U. S. Board of Supervising Inspectors of Steam Vessels.2 I refer to the sagging and deformation which may result from overloading the boilers for a considerable period-say, several days. This is sometimes unavoidable under the exacting conditions of continuous day-and-night service, and (in spite of all rules and precautions, the occasional careless or unskillful work of attendants. Such a trouble is by no means unknown on shipboard, where this type of boiler is so largely employed. In the case here described, two Morrison suspension-furnaces, of half-inch steel, 14 ft. long and 45 in. in mean diameter, with ? dry-back ? boilers, were necessarily operated somewhat beyond their rated -normal capacity for several months, while a third similar unit was -in process of installation, and during this period, though the boilers were kept perfectly clean, heat seems 'to have been generated slightly faster than it was absorbed by, the water in the boilers. The corrugations of this.

Mar 1, 1905

By K. S. TWITCHEEL

THE different lines leading out from the vocation of a mining engineer are,' perhaps, the most' varied of all the professions. The expedition sent by Charles R. Crane of New York 'as a gift to the Imam Yahia, king of the Yemen, Arabia, was probably unique. Mr. Crane made a visit, in January,1927, to the Imam Yahia at Sanaa, capital of the Yemen. He was received with the utmost cordiality and respect, as his friend- . ship for the ,Arab world is famous; He was 'greatly impressed by the desire of the Imam to develop his country. The Imam stated that he had heard that there were minerals in his country and that he would like to secure engineers to advise him about them and other natural resources.. This seemed such a practical idea, and so greatly appealed to Mr. crane, that he offered to furnish an engineering 'expedition. Naturally the Imam gratefully accepted. This expedition was to study (as far as possible in 'the limited time) the natural resources of the ,Yemen, advise the Imam of what these consisted, and make suggestions regarding the most practical methods for their development. As agriculture is always such a fundamental part of a country's wealth, I first went to Indio, California, to study water-well drilling and the date industry, and eventually arrived at Hodeidah, the principal Yemen seaport, on Oct. 21, 1927.

Jan 1, 1929

By Joseph Jensen

THE history of the normal oil field is supposed to show an oil graph stalting high in flush production, descending more or less steeply into the curve of settled production and dropping gradually to the vanishing point of economical operation. Together with this at somewhere in the early history of the field, there appears from a vanishing point a graph showing the production of water. During the period of settled production this graph rises higher and, toward the close, unless extensive work is done in the line of correction, rises far above the oil graph to where the cost of operation terminates profitable pumping. Fields that start out with a high relative content of water are generally very short lived. Fields that never develop a water problem are exceedingly rare.

Jan 1, 1930

By John W. Vanderwilt

THE Climax district is in northeastern Lake County, Colorado, on Fremont Pass (elevation 11,320 ft.) where the continental divide runs east-west joining high peaks of the Mosquito Range with the Sawatch Range, prominent ranges of the central Rocky Mountains. The mining towns of Leadville and Kokomo are thirteen miles to the south and seven miles to the northwest, respectively. Good highways lead to Denver (100 miles) by way of Kokomo, Loveland Pass, and Idaho Springs, and to Colorado Springs by way of Leadville. The ore deposit and mine are about one mile east of Fremont Pass and 600 ft. higher on the southwestern flank of Bartlett Mountain, a peak in the Mosquito Range. The molybdenite deposit lies within the Colorado mineral belt extending across the Rocky Mountains from Jamestown and Boulder to Silverton and Telluride. (See Fig. 1.) Fremont Pass is a broad open divide separating the drainage of the Tenmile River (Pacific) from that of the East Fork of the Arkansas River (Atlantic) ; but the mountains to the east and west are extremely rugged; altitudes in the vicinity vary from 11,000 to 14,000 ft. A conspicuous topographic feature within the district is the Tenmile Amphitheater, which lies east of Climax and

Jan 1, 1946

W. L. Saunders, New York, N. Y.:—Mr. Parker's paper, though entitled Conservation of Coal, might also be called the Conservation of Life in the Coal-Mines of the United States. No subject is of greater importance to mining-men at the present time than information from experts as to how to save coal and how to save human lives in mines. That the casualties in the coal-mines should exceed 3,000 in the year 1907 is simply appalling, and that 1,000 men should have been killed in a single year through explosions alone, and that so good an authority as Mr. Parker should say that " a prolific cause " is an "improperly-prepared blast" or "the failure on the part of the miner to undercut his coal," points to the importance of activity not only among mining engineers but also, through experts, by the legislatures of the respective States. There is but little doubt that nearly all the serious coal-mine

Jan 1, 1910

By E. J. ENGEL

The New York talc deposits of commercial importance are in St. Lawrence and Lewis counties, in the northwest Adirondack Mountains (Fig 1). All of the deposits are of pre-Cambrian age and occur within highly deformed and recrystallized marble of the Grenville series. The deposits in St. Lawrence County, near Gouverneur, are the largest and most productive of their type known in the Western Hemisphere. In 1948 the seven mines which are in operation will produce about 130,000 tons of ground talc. All talc production in Lewis County is from one mine. There the annual production ranges from 15,000 to 30,000 tons. These so called talcs of New York State include earth materials of differ- ent chemical and mineral compositions. In general the mineral talc is sub- ordinate in amount to other minerals in both the Gouverneur and Natural Bridge deposits.

Jan 1, 1949

By Scott Tzcrner

WITHIN recent years people have begun to realize the importance and significance of the mining and allied industries. The leading part the engineer plays in civilization is becoming recognized. However accurate quantitative knowledge of the industrial importance of mining is still seldom possessed except by those close to this business. It is true that there are a few who go to the extreme and represent the whole progress of civilization as a reflection of man's gradual mastery of mineral utilization, but on the whole, the magnitude of the-industry is underestimated. In this paper I shall call attention briefly to the importance of mining in the United States, in Canada, and in the world. Ordinarily, the annual primary mineral production of the United States is about $5,500,000,000. The average for the last 5 years has been a little over that, but last year, sadly enough, it was less than 31/4 billion. Just now, we are on the decline, and have been for the last two years. In Canada, the 5-year average was about $268,000,000, and last year it was 227 million. Due in part to gold mines (in 1930, for the first time, Canada's gold production exceeded that of the United States), the Canadian average is holding up better than ours. Average world mineral production over the last -5 years has been estimated at about $12,000,000;000 whereas in 1931 it was less than than 8 billion.

Jan 1, 1932

By CHARLES W. BENTON

THE following paragraphs comprise such information as the Secretary has been able to obtain concerning the members and associates whose deaths have been reported. Further particulars or corrections of errors, and biographical data concerning deceased members or associates not already noticed in this way, are solicited. Charles IV. Benton was born at Kezar Falls, Maine, Nov. 12, 1843. We have no accurate knowledge concerning the early part of his career. In 1871 he engaged with the N. Y. Honduras Rosario Mining Co., at San Juancinto, Honduras, C. A., and later was employed at the Monserrat mine at Yuscaran, and at Santa Lucia, Honduras, with the Tenero Mining Milling Co. of Pennsylvania. In 1897 he became a member of the Institute. At the time he was stricken with his last sickness he was employed at the Paymaster mine at Tucson, Ariz. He died at Fairmount, Denver, Colo., Sept. 9, 1907. William R. Boggs, Jr.-The notice in the Bulletin for January was incorrect in saying that the murder of Mr. Boggs occurred while he was employed as metallurgical. manager by Mr. W. B. A. Dingwall, at La Maroma, San Luis Potosi, Mex. Mr. Dingwall writes that in March, 1907, Mr. Boggs left him, to return to his home at Winston, N. C., whence he. subsequently went to Durango, Mex., to take, with the Topia Mining Co., a position which he occupied at the tine of his death, Nov. 17, 1907. Mr. Dingwall says that, while in his service, Mr. Boggs never had any trouble with the workmen, but was esteemed and liked by them, as by all who knew him ; and adds, injustice to the State of San Luis Potosi, that the population, even in the mining-camps of that State, is orderly and law-abiding, and that the authorities are vigilant and just. Our

Mar 1, 1908

By Fred H. Lippold, Wm. H. Wolf

Methods of fair payment for excavating, supporting, and concrete lining tunnels have been sought by various owners for years. Tunneling techniques have changed with the development of equipment-from the hand-mucking operation to the machine mucker and, most recently, to machine-boring; from tunnel supports using timber sets to steel sets to rock bolts and, most recently, to shotcrete support; and from hand-placing the concrete lining using wooden forms to pumping or pneumatic placing using steel forms. As tunnel construction techniques advanced, so did methods for payment for the work performed. The recent development of tunnel-boring machines, or "moles," is precipitating another change. These changes have led to some difficulty in providing proper payment for the various items of work for different types of tunnels. As a major construction agency engaged in water-resources development in the western states, the U.S. Bureau of Reclamation has long been aware of the need for clarification of payment provisions in tunnel construction. The Bureau has some 150 miles of tunnels completed on its projects and about 50 miles of tunnels under construction. In this construction, the Bureau has benefited by the advance made by contractors in improving the techniques of tunnel excavation. To assure that the Bureau has an up-to-date approach to payment provisions, the Chief Engineer recently established a "standard" method of payment for all types of tunnels. It is believed that this new method of payment will be equitable for all contractors bidding on various types of tunnels using the diversity of methods of excavation now available to them. These payment provisions provide for different quantities for excavated tunnels using the blasting technique or using machine-boring techniques. In this way, the contractors have a choice in excavation methods and an equal opportunity to be low in their bids. We believe this will be an incentive to all contractors to be as progressive as the development of new equipment economically allows.

Jan 1, 1970

By AIME AIME

THE fall meeting at El Paso this year (Oct. 13¬15) will be of unusual interest due to the international atmosphere imparted by the many engineers from Mexico, who are making arrangements to attend this meeting. The meeting will be held jointly with the Western Division of the American Mining Congress. Cooperating in the program will be the representative society of Mexican engineers known as Centro National de Ingenieros of Mexico City, who are plan¬ning on sending many delegates and well known Mexican engineers to the convention. The cooperation of the West Texas Geological Society and the American Association of Petroleum Geologists has also been secured. Brent N. Rickard, manager of the El Paso Smelting Works of the American Smelting & Refining Co. at El Paso, Tex., is general chairman in charge of arrangements. He is receiving splendid cooperation from the Mining Department of the El Paso Chamber of Commerce and from the business people of El Paso, who feel highly honored in having these mining societies meet with them this year.

Jan 1, 1930

By J. George Gregr

INTRODUCTION This part contains field case studies of typical mishaps, accidents, equipment damage or post installation failures resulting from mistakes in design, manufacturing and construction, as well as improper storage, handling and installation procedures of the equipment covered in Part 1. GENERAL Certain mistakes are repeated and common rules violated on almost all industrial equipment installations, with the inevitable consequences of additional cost, construction delays and aggravation of all parties involved. The most common failures are in the following areas: Cleanliness of all components during installation and later in operation. Adherance to manufacturer' s recommendations and tolerances for equipment installation. Comprehensive, properly identified installation and maintenance records. Handling of the components. Adequate tooling and auxiliary equipment in working order. An inoperable hydraulic power unit for torque wrench or for jacking of the mill, or faulty crane can be a very costly proposition. A special area in comminution circuits are wear components. Apart from the mill liners, the wear components such as, feed chutes, rock boxes, mill trunnion liners, discharge sumps, etc. are designed to the best theoretical configuration, based on experiences in similar installations. However, each process is different to a various degree, mainly because of various types of ores and grinding requirements. Consequently the first generation of wear components is very seldom the ideal one. Based on operational experience, the shape and material of wear components should be modified, until the optimum, most economical design is achieved. SHIPPING AND STORAGE Considerable damage to the equipment can be done by careless packing, shipping or storage.

Jan 1, 1982

By William F. Boericke

KIRKLAND LAKE and Porcupine in 1931 accounted for more than $41,625,000 of Ontario's total gold production of $43,117,688. For the first time, the younger camp surpassed the older in gold output, producing $21,734,000 against $19,891,000 for Porcupine. Present output of both camps is increasing, and should pass the record figures of 1931 before the year is out. In May of this year, Porcupine mines milled 285,759 tons, with a bullion value of $1,810,009; the corresponding figures for Kirkland mines are 149,188 tons and $2,104,757. A much higher average value per ton for Kirkland ore, $14.10 against $6.33 average for Porcupine accounts for the difference. The two fields are about 100 miles apart by rail, and there are important differences in the character of the ores, which accounts largely for the difference in milling costs and in final tailing values, despite excellent metallurgical work in both the fields.

Jan 1, 1932

By S. S. Clarke

ABOUT two years ago some of my friends were discussing the amount of drill-steel breakage that was permissible or not excessive, per month, per rock ton, per ton of steel or any unit of measure or output that would give a comparison between different kinds of drill steel. No one seemed to know what life to expect of steel, or what percentage of breakage might be termed excessive. In fact there were no operating data available to guide one in selecting the best steel for our mines, nor could any ideas or information be secured from the steel manufacturers. One was merely told that so and so used their steel and it was very satisfactory; or else one was given a highly technical lecture on their specific heat-treatment. Any estimates on expected breakage were just guesses, ranging from a fraction of a per cent to as high as ten per cent per month.

Jan 1, 1933

By Benjamin C. Craft

A review of development in North Louisiana during 1936 centers around the Rodessa field, in Caddo Parish. Continued extension of the

Jan 1, 1937

By Donald H. McLaughlin

ZEST in the search for new supplies of metallic ores and petroleum is difficult to maintain with stocks of raw materials accumulating and with over- production rightly or wrongly blamed for most of our industrial troubles. Enthusiasm over new methods of prospecting has consequently diminished and exploration programs in many fields have been drastically cur- tailed. Very naturally the effects have been felt with particular keeness in highly specialized phases of the work, such as geophysical prospecting, for the feverish scramble for new areas in which to drill beneath magnetic or electrical anomalies has abated, and there is even a lull in the firing in the battle over salt domes on the Gulf Coast. It is unquestionably an unhappy time for many of the organizations dependent on this work, but in certain respects the situation may be beneficial in correcting unsound practices that .have grown up through the necessity for haste and for quick decisions. With the restriction of the field to the more competent workers by the harsh rule of survival of the fittest, a general improvement, not only in technique but in business methods, can be expected which may go far in restoring public confidence. Geophysical prospecting in the short period that it has been utilized in North America, has suffered severely both from over-popularity and from excessive abuse. The former evil now

Jan 1, 1931

By AIME AIME

WITH the example of the steel open-hearth men and their round table conference before the copper men, the query naturally arose "Why cannot we do likewise?" The advantage of pooling and comparing knowledge on smelting in the copper reverberatory furnace seems particularly pertinent at this time when all metallurgical economies possible must be rigorously enforced. A great deal of data had also been obtained and filed during the period of litigation over the Carson patent, and it would naturally be available with the cessation of further suits. With these ideas in mind, H. Foster Bain took up the advisability of holding such a conference directly with the heads of all the companies in the United States operating copper reverberatories, and found a nearly unanimous response. The mining companies appointed representatives directly, or indicated to the heads of various metallurgical operations what members of their staffs should be sent to such a conference.

Jan 1, 1930

By E. J. KENNEDY

METHODICAL AND EFFECTIVE: thus may be characterized the fall meeting of the Iron and Steel and Institute of Metals Divisions at the Hotel Statler, Buffalo, N. Y., on Oct. 4 and 5. Approximately 200 registered. Interest centered 1111 the technical papers which were keenly followed, with substantial discussion: During the entire week of the National Metal Congress (Oct. 3 to 'i), there were also other sessions of interest' to metallurgists, directed by the America11 Society for Steel Treating, American Welding Society, Production Division of the Society of Automotive Engineers, the Iron arid Steel and Machine Shop Practice Divisions of the American Society of Mechanical En,' the Wire Association and the American Drop Forging Institute. The National Metals Exposition at the 174th Regiment Armory was well attended.

Jan 1, 1932

By L. F. Pett

ALTHOUGH Kennecott's orebody has long been outlined, it is still necessary to define further its limits. This mine, long an advocate of churn drill methods, recently supplemented its practice by using a diamond drill. So far, the diamond drill holes have been along the main canyon floor which traverses the mine area. This zone, highly fractured, is cut by numerous friable quartz veinlets encountered within the porphyry. These veinlets, formed by filling contracted porphyry fractures with hot, siliceous, mineral-bearing solutions, are often more highly mineralized than adjacent porphyry. They pulverize on contact, yielding only slight amounts of core.

Jan 7, 1951