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By Maja Franjic, Ian Tolliday, Chris Collins, James Wiltshire

Ammonium Nitrate Emulsions (ANE) are a large segment of the explosives market for the mining industry. These emulsions are generally designed to be very stable but when breakdown does occur, removal of the resulting thick, crystallized material can be difficult, hazardous, time consuming and costly. A heavily crystallized emulsion cannot be pumped, so manual removal often becomes necessary. Buildup of semi-solid layers of crystallized emulsion can occur in bulk storage tanks or in truck compartments. In these situations, a manual cleanup involving hazardous confined-space entry and a significant amount of downtime is usually required. Once the crystallized emulsion is removed from the equipment, there is very expensive disposal of the resultant waste via a licensed trade-waste company. A much more desirable solution for dealing with waste emulsion is to completely break the emulsion, allowing the oxidizer and fuel phases to separate into two distinct layers. These layers would then be readily pumpable and could be disposed of much more economically. It may even be possible that the separated oxidizer phase could be repurposed as fertilizer and the fuel phase could be used to manufacture granular ANFO explosives. There are some existing products on the market for breaking emulsion explosives, but these generally need a high degree of mixing into the emulsion to achieve adequate breakdown. The aim of this study was to identify surfactants systems (demulsifiers) capable of effectively breaking a range of waste emulsions with minimized agitation. This paper describes the development and performance testing of novel demulsifier products. The test work involved a comprehensive series of laboratory screening tests, where the demulsifier formulations were optimized. A highly efficient formulation was identified, and field trials were conducted on real world, full-scale waste emulsions. Results will be presented that demonstrate a viable solution for the disposal, and potential re-use, of waste ANE in the explosives industry.

Jan 21, 2025

By Eric Eisold

The Wachovia Headquarters and Arts and Cultural Campus project in Charlotte, NC includes a 1.5 million square foot, 48-story office tower, two museums, an Afro-American cultural center and a 1,200 seat theater for the performing arts. Public access to the Cultural Campus is through two pedestrian tunnels constructed under city streets connecting to parking garages. The 5.7 m wide by 4.7 m high mined tunnels were procured through a design-build contract. The tunnels were designed as initial/final shotcrete linings with a sprayed water barrier sandwiched between layers of shotcrete. In addition, the mix design was supplemented with a cementitious admixture to develop internal water resistant properties in the shotcrete.

By Fernanda Margarido

Recovery of metals contained in the electrode materials of batteries was studied considering an integrated recycling process constituted by physical and chemical operations. The physical treatment included the shredding of the spent batteries, followed by a wet sieving operation of the fragmented material. The physical behavior of Ni-Cd and Zn-Mn based (alkaline and saline) system batteries was studied and compared. In that sense, shredding operation was performed and the sieving of shredded fractions was accomplished to evaluate the efficiency of the separation of electrodes and scrap. For Ni-Cd batteries the loss of electrode material with the supra fraction (scrap) after the shredding operation was lesser than the Zn-Mn batteries. Especially for saline-type batteries, the electrode attached to the scrap was substantial leading to important losses. This difference can be explained by the composition of the case materials and the internal physical constitution of the electrodes. The wet sieving studies carried out allowed optimizing the separation of the electrode fine fractions from the scrap materials through the analysis of selectivity Cd/Fe or Zn/Fe. For Ni-Cd batteries, maximum selectivity was achieved for the granulometry of 1.4 mm, while for alkaline and saline systems best selectivity were obtained at 2.8 mm and 5.6 mm, respectively. This process allowed the recovery of about 70% of electrodes for Ni-Cd and alkaline systems, and 50% for saline batteries, with less than 5% of scrap as contaminant. This physical step can be considered as a pre-treatment of this type of waste material envisaging its valorization by chemical treatment, as improves the concentration of the elements of interest and decreases the iron content.

Jan 1, 2006

By Juan Ayza

En este último artículo se describe el sistema de IMPINGER - como parte del muestreo y así determinar la cantidad de polvo adherido. Dicho sistema produce una presión negativa sobre el agua de un tubo, y es donde la presión atmosférica introduce el aire por un tubo central, cuya boquija está debajo del agua y a 5 mm. del fondo. En ese sentido, la mayor cantidad polvo queda en suspensión. De otro lado, se describe el método cualitativo cinematográfico donde se percibe la cantidad de polvo a través de la captación de luz fotográfica, aunque el problema es el avaluúo preciso de la sílice li-bre en el rango de polvo respirable.

Mar 1, 1956

By John P. Turner, Mark Jen, Bobby Daita

"The Port Authority of New York and New Jersey is replacing the existing Goethals Bridge built in 1928 which is deemed to be functionally obsolete. The replacement bridge will consist of a dual cable-stayed Main Bridge crossing the Arthur Kill with elevated approach spans connecting Elizabeth, New Jersey and Staten Island, New York. The main bridge towers are supported on a group of six nine-foot diameter drilled shafts that transition into a pier cap. The anchor and approach piers are supported on two column bents with each column supported on a single drilled shaft. The 4.5 to 10 feet diameter drilled shaft foundations have permanent steel casing to rock and socketed into bedrock. Subsurface conditions consist of Passaic Formation bedrock overlain by varying thicknesses of overburden soils. The foundation design assumes permanent casing extending a minimum 2 feet into the weathered bedrock. Rock socket lengths below the permanent casing vary between one to two shaft diameters based on the quality of the bedrock. The reinforcing design was based on AASHTO LRFD minimum requirements, force demands, seismic detailing requirements and also considering the continuity between the shaft and socket.The bridge is currently under construction with approximately 70 percent of the foundations installed. Several field conditions encountered at various stages of shaft construction between casing advancement and concreting required design and construction modifications. Based on the driving method and the quality of the bedrock, the tip of the permanent casing hit refusal either above or below the design elevation, requiring modifications to the drilled shaft design and its reinforcement. This paper provides an overview of the general subsurface conditions at the site and its impact on foundation design and discusses the detailing worked into the design to accommodate tip elevation variations, as well as various foundation design modifications in response to actual conditions encountered during construction."

Jan 1, 2016

By P. Groleau, O. Tavchandjian, D. Marcotte

In open pit mining, each small mining unit (SMU) is selected for mill processing based on an estimate of its true grade. The estimation is usually done using analyses of cuttings from blast holes within that SMU. One common estimator used for selection is the arithmetic average of within-SMU samples. This estimator is conditionally biased. The effect of a conditional bias is to overestimate the profit really recovered from the deposit. For this reason, a conditionally unbiased estimator is preferable. Increasing the number of samples generally improves the accuracy of the estimation (and diminishes the conditional bias, if present, of most estimators). However, there exists a practical limit where an additional sample does not improve the estimation sufficiently to cover the expense of making the analysis. This limit is specific to each deposit and depends on geostatistical parameters, economic factors, and mining parameters. This study examines how the number of samples affects the recovered reserves and the resulting profit. Also, the effects on optimal profit of varying the different factors are examined. Globally, the number of samples required increases with the selectivity of the operation. For a given ore deposit, the greater the number of SMUs selected for processing, the fewer samples are required and vice-versa.

Jan 1, 1998

By Frank J. Arland

Augered-Cast-in-Place piles have been used successfully for many deep foundation applications. The four case studies discussed herein describe ACIP pile projects where problems developed during ACIP pile installation requiring changes to the method or sequence of installation. The case studies illustrate the importance of understanding existing subsurface conditions and project constraints when considering the use of this pile type. Ground loosening and over-excavation of soil during the augering process, a significant concern for fine to medium sands and non-plastic silts below the water table, can significantly impact adjacent structures. This risk needs to be evaluated during the pile selection process and generally can be mitigated, but not eliminated, by requiring the use of piling equipment with high torque and slow auger rotation speed to advance the auger with minimum amount of rotation. In some applications where high lateral stresses in the soil are present such as at the base of retaining structures, the use of ACIP piles may not be appropriate if structure movement is unacceptable. On the other hand, ACIP piles have been successfully used to support deep foundations in preconsolidated varved deposits where the new structure was designed to accommodate recompression settlement.

Jan 1, 2004

By Junwei Han, Wenqing Qin, Dawei Wang, Fen Jiao, Wei Liu

The removal of iron impurity from zinc calcine was studied by magnetization roasting and magnetic separation. The effects of roasting temperature, magnetic intensity, ore grinding, and leaching pretreatment on iron grade and recovery were investigated. The results indicated that iron recovery increased with the increase of roasting temperature or magnetic intensity, while iron grade was always less than 22%, depending on the fact that the magnetite were not liberated completely. The good liberation was difficult to be achieved by ore grinding but was easier by acid leaching, since the magnetite grains were very fine. After the leaching pretreatment, the recovery of 76.31% with iron grade of 53.24% was obtained by one roughing and cleaning. The SEM/EDS analysis showed that a part of sphalerite, zinc ferrite and other gangues were mixed into the iron concentrate, while some of fine magnetite was reported to the tailing.

Jan 1, 2016

By M. J. Pool, R. K. Saxer, J. R. Myers, D. S. Dickson

ThE equilibrium phase diagram of the Mo-Cr system, described by anssen,' indicates that chromium and molybdenum form a continuous series of solid solutions above 1673K. The liquidus and solidus have been reported to have a minimum at about 12 at. pct Mo and 2133°K by Bloom and Grant2 and by Putnam, Potter, and Grant.3 X-ray studies by Trzebiatowski and ploszek4 and Baen and Duwez' revealed no indication of solid solution decomposition after long anneals at 1473", 1273", 923", and 873°K. However, Bloom and rant' by means of cooling and heating curve analysis of alloys containing up to 45 at. pct Mo found thermal effects at temperatures approximately 100" * 30°K below the liquidus. The only previous thermodynamic study of the Cr-Mo alloy system was made by Laffitte and Kuba-schewski6 who used the Knudsen effusion method at 1471°K. These investigators reported the possibility of a miscibility gap because they observed positive deviations from ideality in their chemical activity

Jan 1, 1970

By M. Falutsu

"The PSI-200 is a rugged, innovative, and easy to install on-stream size analyzer. Its calibration is simple and can be done on-line, during operation. Two measurements are displayed on the panel, which are expressed as percent passing a selected size, or as any statistical diameter. These two measurements are given as two continuous 4-20 mA output signals. Operation alarms are displayed on the screen or are given as digital output signals.The PSI-200 has been used in various applications at Lakefield Research. Particle sizes ranging from 10 µm to 450 µm have been monitored successfully, with an accuracy of 1- 2%. Having the size measured continuously and reliably, optimum conditions have been established for the grinding circuit, resulting in a superior quality in pilot plant testing.INTRODUCTIONThe challenge of any operating plant is to optimize product quality, maximize throughput and minimize operating costs. The importance of particle size measurement at a grinding circuit is well recognized. Monitoring continuously the particle size and keeping the product as uniform as possible is crucial to the whole mill operation regardless of the nature of the operation.Various techniques and instruments have been developed over the years attempting to give reliable on-line size analysis data. The operating difficulties and the reliability of these equipment still present major drawbacks and none of them proved to be widely accepted.PSI-200 is a relatively new on-line analyzer. The operation is simple and of low cost and the maintenance required minimal. It measures particle size and it displays two parameters of the solids size distribution, either weight fraction of passing a certain size or any statistical diameter. Two analog outputs can be sent to a process control system and through a supervisory control loop the correct action can be taken to maintain the desired particle size (perhaps adjust the feed rate to the grinding mill)."

Jan 1, 1993

By Archer Wheeler

THE copper industry in the Province of Katanga, in the Belgian Congo, which is now controlled and operated by the Union Minere du Haut Katanga, had its inception many years ago in the vision of a Scotsman, Robert Williams, now Sir Robert Williams, Baronet. He it was who personally negotiated the mineral concession with King Leopold of Belgium, sent in the prospecting parties who located most of the present mines of the company, later arranged for the Belgian participation from which the present company was formed, and has been its active mentor ever since. The idea back of his efforts was the establishment of an industry on the Congo-Zambezi divide, of sufficient importance to draw up to it the head of the Cape to Cairo Railroad, the dream of Sir Cecil Rhodes, and the consummation of which he had left as a legacy to Mr. Williams, his successor. The reports of the prospecting expeditions showed that copper in profitable quantity was there, but many difficulties lay in the way of the establishment of the infant industry. The isolated location of the mines, various tribal wars, the Boer War, and many other factors contributed to making progress very slow. However, in spite of these difficulties the railroad was finally built and a blast-furnace plant erected at Lubumbashi, near Elisabethville, the capital of the Province. Operations of this plant were started in 1911, treating high-grade oxidized ores and producing pig copper by a reducing smelting. Production has been continuous since that time and the company has grown so that at present it ranks as the largest individual copper producer in the industry. It is a fitting monument to the foresight, optimism and driving force of its founder, and the progressive policies of his Belgian colleagues. In January, 1914, the Union Miniere du Haut Katanga engaged as its consulting engineer, Archer E. Wheeler, metallurgical engineer, at that time general superintendent of the Great Falls plant of the Anaconda Copper Mining Co. Mr. Wheeler was commissioned by the Board of Directors to proceed into Katanga, and make all necessary investigations to enable him to report on a comprehensive development program, and to recommend a scheme of treatment particularly for their low grade

Jan 1, 1932

By H. C. Ray

ABOUT the beginning of 1930, coal preparation had reached the stage where the cleaning of coal by liquid or air had become the order of the day. Since that time many new preparation plants have been installed in spite of the years of depression in the coal industry, and this is indicative of a trend wherein the coal producer found it expedient to manufacture a cleaner product in order to compete with other fuels. It was also about 1930 that, because of the difficulties encountered with fine coal in cleaning plants, dust collectors came into use. Both cleaning plants and dust collectors, therefore, were much discussed at the engineering meetings of the early 1930's. During these meetings the many advantages to be gained through the use of dust-collecting systems were pointed out by Hebley,1 Appleyard2 and others. The great possibilities of new markets for this product were emphasized and discussed at the same time; however, the disposal of the collected dust remained a problem. Since the purpose of dust collecting is to improve the preparation and, consequently, the salability of the coal, it seems illogical to return the collected dust to any of the coal being prepared for market use, as is done in preparation plants that include dust-collecting systems. The logical thing is to dispose of the dust in some useful and practical manner outside of the tipple. As a practical matter, this can be done in one or both of two ways; either by consuming the dust at the mine's own power plant or by marketing the dust direct to the consumer. The latter method not only offers the greatest opportunities, but is the most important, because of inequalities that may exist between the quantity of dust collected and the consuming capacity of the mine's power plant. In considering the more important marketing possibilities, we are confronted immediately with the problems connected with the handling and transportation of so fine a material. It is this problem, rather than the problem of finding new markets, that has been responsible for the lack of progress in the matter of dust disposal. It is the purpose of this paper to point out again some of the potential market outlets, and also to describe an existing system of handling and transporting coal dust. To the best of the writer's knowledge, this is the first and only operation in this country that has handled fine-mesh coal in bulk 50-ton lots direct to the consumer. POtential Markets for Fine-mesh Coal Dust In general, the potential market outlets would include any operation of which the pulverization of coal is a necessary part. To be more specific, a few of the better known operations of this type must include: colloidal-fuel plants, briquetting plants, "sea coal" distributing plants, water-purification plants and, obviously, pow-

Jan 1, 1944

By H. C. Ray

ABOUT the beginning of 1930, coal preparation had reached the stage where the cleaning of coal by liquid or air had become the order of the day. Since that time many new preparation plants have been installed in spite of the years of depression in the coal industry, and this is indicative of a trend wherein the coal producer found it expedient to manufacture a cleaner product in order to compete with other fuels. It was also about 1930 that, because of the difficulties encountered with fine coal in cleaning plants, dust collectors came into use. Both cleaning plants and dust collectors, therefore, were much discussed at the engineering meetings of the early 1930's. During these meetings the many advantages to be gained through the use of dust- collecting systems were pointed out by Hebley,1 Appleyard2 and others. The great possibilities of new markets for this product were emphasized and discussed at the same time; however, the disposal of the collected dust remained a problem. Since the purpose of dust collecting is to improve the preparation and, consequently, the salability of the coal, it seems illogical to return the collected dust to any of the coal being prepared for market use, as is done in preparation plants that include dust-collecting systems. The logical thing is to dispose of the dust in some useful and practical manner outside of the tipple. As a practical matter, this can be done in one or both of two ways; either by consuming the dust at the mine's own power plant or by marketing the dust direct to the consumer. The latter method not only offers the greatest opportunities, but is the most important, because of inequalities that may exist between the quantity of dust collected and the consuming capacity of the mine's power plant. In considering the more important marketing possibilities, we are confronted immediately with the problems connected with the handling and transportation of so fine a material. It is this problem, rather than the problem of finding new markets, that has been responsible for the lack of progress in the matter of dust disposal. It is the purpose of this paper to point out again some of the potential market out- lets, and also to describe an existing system of handling and transporting coal dust. To the best of the writer's knowledge, this is the first and only operation in this country that has handled fine-mesh coal in bulk so-ton lots direct to the consumer. POTENTIAL MARKETS FOR FINE- MESH COAL DUST In general, the potential market outlets would include any operation of which the pulverization of coal is a necessary part. To be more specific, a few of the better known operations of this type must include: colloidal-fuel plants, briquetting plants, “sea coal” distributing plants, water-purification plants and obviously, pow-

Jan 1, 1944

By H. C. Ray

ABOUT the beginning of 1930, coal preparation had reached the stage where the cleaning of coal by liquid or air had become the order of the day. Since that time many new preparation plants have been installed in spite of the years of depression in the coal industry, and this is indicative of a trend wherein the coal producer found it expedient to manufacture a cleaner product in order to compete with other fuels. It was also about 1930 that, because of the difficulties encountered with fine coal in cleaning plants, dust collectors came into use. Both cleaning plants and dust collectors, therefore, were much discussed at the engineering meetings of the early 1930's. During these meetings the many advantages to be gained through the use of dust-collecting systems were pointed out by Hebley,1 Appleyard2 and others. The great possibilities of new markets for this product were emphasized and discussed at the same time; however, the disposal of the collected dust remained a problem. Since the purpose of dust collecting is to improve the preparation and, consequently, the salability of the coal, it seems illogical to return the collected dust to any of the coal being prepared for market use, as is done in preparation plants that include dust-collecting systems. The logical thing is to dispose of the dust in some useful and practical manner outside of the tipple. As a practical matter, this can be done in one or both of two ways; either by consuming the dust at the mine's own power plant or by marketing the dust direct to the consumer. The latter method not only offers the greatest opportunities, but is the most important, because of inequalities that may exist between the quantity of dust collected and the consuming capacity of the mine's power plant. In considering the more important marketing possibilities, we are confronted immediately with the problems connected with the handling and transportation of so fine a material. It is this problem, rather than the problem of finding new markets, that has been responsible for the lack of progress in the matter of dust disposal. It is the purpose of this paper to point out again some of the potential market outlets, and also to describe an existing system of handling and transporting coal dust. To the best of the writer's knowledge, this is the first and only operation in this country that has handled fine-mesh coal in bulk 50-ton lots direct to the consumer. POtential Markets for Fine-mesh Coal Dust In general, the potential market outlets would include any operation of which the pulverization of coal is a necessary part. To be more specific, a few of the better known operations of this type must include: colloidal-fuel plants, briquetting plants, "sea coal" distributing plants, water-purification plants and, obviously, pow-

Jan 1, 1944

By Fred Kissell

The Bureau of Mines has developed the shearer-clearer--a new type of dust control system for longwall shearers. The system partitions the airflow around the shearer into a clean split and a contaminated split. The dust cloud is confined to the vicinity of the coal face, while the shearer operators remain in the clean split on the gob side of the machine. The shearer-clearer operates on the principle that each water spray moves air like a small fan and can be positioned to direct the dusty air towards the face. The hardware is inexpensive and can be installed in a single shift. It consists of several strategically mounted water sprays and one or more passive barriers. Laboratory testing indicates reductions 1n shearer operator dust exposure as high as 97 pct. Preliminary results from an underground demonstration in one mine also indicate that considerable dust reductions at the shearer may be obtained. In conjunction with the development of the shearer-clearer, dust surveys were conducted in three other mines to determine if some shearer spray systems currently in use partition the flow in a manner similar to the shearer-clearer, and if so, whether this partially accounts for markedly cleaner conditions on some longwalls. Results from these surveys indicate this to be the case. A feature of the cleaner longwalls was a downwind orientation of their water sprays, which is a key element of the shearer-clearer system. The shearer-clearer system described in this report was designed for an Eickhoff EDW 300 shearer working a 7-foot coal seam. The testing to date has concentrated on cutting directions counter to the primary airflow. The development effort continues for different mining equipment and conditions. It is expected that different systems will be required to accommodate the range of conditions occurring underground. Application of the system presented here to conditions different than those described is not likely to produce the same results.

Jan 1, 1981

By J. Murray Riddell, Grover J. Holt, Arthur E. Anderson

Out of the depths of each business cycle we emerge with a stimulus for greater efficiency and a realization of progress in industrial technique. The recent years have not been an exception to this rule, and in retrospect we sense that significant advances have been made in mining practices on the Mesabi Range, with emphasis on speed of production and economy of operation. A survey of such changes does not reveal anything that is fundamentally or basically new, but it is apparent that ideas and machines that have found wide application in industry elsewhere, with necessary modifications, are being put to productive use in mining iron ore. Innovations in transporting and conveying ore from the open pits stand out with greatest prominence, so that, in the main, it will be with these features that this paper will treat, in the review of progress made to this date. The late years have witnessed the development of small deposits for open-pit operation, the cleaning up of pits nearing exhaustion, and in two large operations the approach to the limit for haulage by steam locomotives, owing to grades, making it necessary to recover the ore in slopes, track benches and below the power-shovel limit by a milling and scram operation. For several years small standard-type dump trucks have been used in clean-up or scram operations within the pits, but during the season of 1936 the first effort was made to use heavy truck haulage in the transportation of stripping and iron ore. The new units in use today vary from 15 to 20 tons in capacity, and are equipped with powerful gasoline or Diesel engines and supplemented by trailers or wagons on rubber or crawler treads. The Diesel engine finds favor with most operators because of fuel economy. These units develop upward of 125 hp. in the 15-ton trucks. The speed of these trucks varies from 2 miles per hour in Pow gear to 35 in high gear. The transmission affords 12 speeds forward and 3 speeds in reverse.

Jan 1, 1940

By J. Murray Riddell, Arthur E. Anderson, Grover J. Holt

Out of the depths of each business cycle we emerge with a stimulus for greater efficiency and a realization of progress in industrial technique. The recent years have not been an exception to this rule, and in retrospect we sense that significant advances have been made in mining practices on the Mesabi Range, with emphasis on speed of production and economy of operation. A survey of such changes does not reveal anything that is fundamentally or basically new, but it is apparent that ideas and machines that have found wide application in industry elsewhere, with necessary modifications, are being put to productive use in mining iron ore. Innovations in transporting and conveying ore from the open pits stand out with greatest prominence, so that, in the main, it will be with these features that this paper will treat, in the review of progress made to this date. The late years have witnessed the development of small deposits for open-pit operation, the cleaning up of pits nearing exhaustion, and in two large operations the approach to the limit for haulage by steam locomotives, owing to grades, making it necessary to recover the ore in slopes, track benches and below the power-shovel limit by a milling and scram operation. For several years small standard-type dump trucks have been used in clean-up or scram operations within the pits, but during the season of 1936 the first effort was made to use heavy truck haulage in the transportation of stripping and iron ore. The new units in use today vary from 15 to 20 tons in capacity, and are equipped with powerful gasoline or Diesel engines and supplemented by trailers or wagons on rubber or crawler treads. The Diesel engine finds favor with most operators because of fuel economy. These units develop upward of 125 hp. in the 15-ton trucks. The speed of these trucks varies from 2 miles per hour in Pow gear to 35 in high gear. The transmission affords 12 speeds forward and 3 speeds in reverse.

Jan 1, 1940

By J. Murray Riddell, Arthur E. Anderson, Grover J. Holt

OUT of the depths of each business cycle we emerge with a stimulus for greater efficiency and a realization of progress in industrial technique. The recent years have not been an exception to this rule, and in retrospect we sense that significant advances have been made in mining practices on the Mesabi Range, with emphasis on speed of production and economy of operation. A survey of such changes does not reveal anything that is fundamentally or basically new, but it is apparent that ideas and machines that have found wide application in industry elsewhere, with necessary modifications, are being put to productive use in mining iron ore. Innovations in transporting and conveying ore from the open pits stand out with greatest prominence, so that, in the main, it will be with these features that this paper will treat, in the review of progress made to this date. The late years have witnessed the development of small deposits for open-pit operation, the cleaning up of pits nearing exhaustion, and in two large operations the approach to the limit for haulage by steam locomotives, owing to grades, making it necessary to recover the ore in slopes, track benches and below the power-shovel limit by a milling and scram operation. For several years small standard-type dump trucks have been used in clean-up or scram operations within the pits, but during the seasor1 of 1936 the first effort was made to use heavy truck haulage in the transportation of stripping and iron ore. The new units in use today vary from 15 to 20 tons in capacity, and are equipped with powerful gasoline or Diesel engines and supplemented by trailers or wagons on rubber or crawler treads. The Diesel engine finds favor with most operators because of fuel economy. These units develop upward of 125 hp. in the 15-ton trucks. The speed of these trucks varies from 2 miles per hour in low gear to 35 in high gear. The transmission affords 12 speeds forward and 3 speeds in reverse.

Jan 1, 1938

By H. M. Howe

A Discussion of the paper of Professor Howe, presented at the London Meeting, July, 1906, and printed in Bi-Monthly Bulletin, No. 14, March, 1907, pp. 169 to 274. SECRETARY'S NOTE.-M. Beutter's introductory remarks, being simply a resume of Prof. Howe's paper, with a disclaimer of the intention to criticise it, have been omitted, and the remainder of this contribution has been somewhat condensed, without omitting any essential statements. M. BEUTTER, St. Etienne* (communication to the Secretary-+):-Professor Howe observes in paragraph 47 of his paper that the fluid-compression of steel. diminishes piping by forcing the liquid and viscous metal, while the pipe is forming, or after it has formed, into the space so produced, and proceeds to study the different systems of compression, alluding to the four principal ones: Whitworth, Illingworth, Williams, and Harmet. Having now for many years had in use the last-named process, that of M. Henri Harmet, I shall attempt to explain the difference between it and the three other processes named. The Harmet process does not diminish or close the pipe after it has formed, but prevents it from forming; and I may add that it is the only one of the four which produces this result. It is true that the Whitworth process diminishes the interior hollow by localizing it around the central axis of the ingot, which is afterwards removed by trepanning the hollow forgings for which this process has been, I believe, always exclusively used. The Illingworth and Williams processes, which, in my opinion, are applicable only to small ingots, of necessity allow the pipe to form, or (to use the expression of Professor Howe) they allow the surface of the lake of liquid steel to sink into the interior of the ingot, since they involve waiting a certain time before compression, so that (in the case of the Williams process) the ingot-mold can be opened without dan¬ger, or (in the case of the Illingworth process) so as to avoid the risk that the steel may enter the grooves produced by the removal of the distance-bars. During the time required for

Jul 1, 1907

By G. L. Leumann

"INTRODUCTION AND SUMMARYThe Andover-Sulphur Hill iron mines in Sussex County, N. J., have a production record extending over 100 years. The last production recorded was about 1880. These mines produced high-grade ore of two types: Red ore (hematite) and blue on (magnetite). Some sulfides (lead, zinc, and copper) were found underlying the iron deposits. Data as to size and grade of these sulfide bodies are very sketch"",Howard J. Hewitt of Elizabeth, N. J., lessee of the Sulphur Hill mines from 1940-45, prospected for lead, zinc, and copper. .His only production was several hundred tons of low-grade iron ore, which was crushed and used as heavy aggregate to make concrete blocks for ship ballast.In October and November 1942 made a magnetic survey of this area and bored six-diamond-drill holes with the dual objective of prospecting for sulfides and testing for extensions of the iron-are deposits indicated by the magnetic survey. 2/ In 1944, an iron-mining company examined this property and diamond-drilled seven holes. Between December 1949 and March 1950, the Bureau of Mines in search of sulfide deposits, bored three additional diamond-drill holes. Two of these were on the Sulphur Hill tract and one on the adjoining Tar Hill tract."

Sep 1, 1952