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By C. H. Herty

Almost every metallurgist who has given the Howe Memorial Lecture has had a personal contact with the distinguished gentleman to whose honor this hour is devoted. Unfortunately for me, such personal contacts were not possible. However, in the preparation of a thesis on the open-hearth process, one of my earliest tasks was to make a survey of the literature, and it was from Professor Howe's Metallurgy of Iron and Steel that I drew a number of references to previous work which formed the foundation for my reading. In his volume there is such a complete exposition of the then current thought on the subject of slags and on their role in the elimination of phosphorus from steel that I feel no hesitation in discussing in this Howe Lecture the subject of "Slag Control." In the present era of close specification, the drive for uniformity of product, and the close inspection of the product and of the cost sheet, the utmost efforts must be made to control the steelmaking variables to the best advantage of the steel producer. One of the major variables is the slag in the furnace and its effect upon the composition and quality of the metal. What advantages are to be gained from slag control? In the broad sense the advantages must be tremendous, because the very foundations of good steel melting are based on "shaping up" the slag to a point where, with proper temperature, the heat is ready for the final additions. Every melter works toward these ends through his experience with innumerable heats of steel. The elimination of undesirable constituents such as phosphorus and sulphur is entirely a matter of slag composition and physical nature, a point well known for over half a century. The role played by the slag in assisting in proper heat transfer from roof and flame to the steel has been equally well known. In more recent years there has come the problem of oxygen control in the more accurate gauging of additions for making high-grade rimmed steel for the new strip mills, and in the deoxidizing additions for grain-size control and cleanliness of forging steels, both carbon and alloy. In this problem the oxidizing characteristics of the slag are of prime importance.

Jan 1, 1940

By Gary Beerkircher

The mine hoisting equipment that is selected and installed at a mine is the lifeline of the mine, and therefore the proper selection of equipment will save a lot of time and money during the life of the mine. Various types of mine hoist designs &e available today, and each has their advantages and disadvantages. Double Drum Hoists, Single Drum Hoists, Friction Hoists and various special designs of these are available but should only be used on applications where they are suitable. There have been several new drive systems for mine hoists which have come into the picture in the last ten years, and they in turn must be evaluated along with the existing drive systems for each hoist application. It does not make sense to properly select the hoist mechanicals, and then have a drive system that turns out to be a bottleneck. This paper will attempt to cover the above noted systems - both the hoist selection and hoist drive system that will provide the mine with a reliable and economical hoisting system. I. Mine Hoist Types There are two basic types of mine hoists available in the world today: the drum hoist on which the hoist rope is actually stored during the hoisting cycle, and the friction (Koepe), which merely passes the rope over the wheel during the hoisting process. Following is a general outline of each type of hoist and the hoisting applications that they are suitable for. First let us consider the simple Single Drum Hoist. As a Service or Production Hoist with cage or skip in balance with a counterweight, a Single Drum Hoist can efficiently service one or more levels since the location of the counterweight at anytime is not important. As a Production Hoist with skips in balance the Single Drum Hoist is best used for single level hoisting. All rope adjustments for proper spotting must be done manually for the Single Drum Hoist. This has to be done periodically to compensate for rope stretch. A variation of the Single Drum Hoist is the divided drum hoist. If multi-layer winding is necessary the Single Drum Hoist must have a divider to allow a separate compartment for each rope. If a counterweight is used with a divided drum application the counterweight rope can be wound on a smaller diameter (Figure 2). Consequently, it moves a lesser distance than the main conveyance and rope adjustment problems are reduced.

Jan 1, 1975

By C. H. Herty

Almost every metallurgist who has given the Howe Memorial Lecture has had a personal contact with the distinguished gentleman to whose honor this hour is devoted. Unfortunately for me, such personal contacts were not possible. However, in the preparation of a thesis on the open-hearth process, one of my earliest tasks was to make a survey of the literature, and it was from Professor Howe's Metallurgy of Iron and Steel that I drew a number of references to previous work which formed the foundation for my reading. In his volume there is such a complete exposition of the then current thought on the subject of slags and on their role in the elimination of phosphorus from steel that I feel no hesitation in discussing in this Howe Lecture the subject of "Slag Control." In the present era of close specification, the drive for uniformity of product, and the close inspection of the product and of the cost sheet, the utmost efforts must be made to control the steelmaking variables to the best advantage of the steel producer. One of the major variables is the slag in the furnace and its effect upon the composition and quality of the metal. What advantages are to be gained from slag control? In the broad sense the advantages must be tremendous, because the very foundations of good steel melting are based on "shaping up" the slag to a point where, with proper temperature, the heat is ready for the final additions. Every melter works toward these ends through his experience with innumerable heats of steel. The elimination of undesirable constituents such as phosphorus and sulphur is entirely a matter of slag composition and physical nature, a point well known for over half a century. The role played by the slag in assisting in proper heat transfer from roof and flame to the steel has been equally well known. In more recent years there has come the problem of oxygen control in the more accurate gauging of additions for making high-grade rimmed steel for the new strip mills, and in the deoxidizing additions for grain-size control and cleanliness of forging steels, both carbon and alloy. In this problem the oxidizing characteristics of the slag are of prime importance.

Jan 1, 1940

By Merete Tangstad, Lars Klemet Jakobsson

"Slag refining is a promising refining method for boron removal from silicon as a part of a metallurgical route for production of silicon for solar cells. There is, however, limited data on the distribution of impurity elements between silicon and different types of slags. In the present study, the distribution of boron and calcium between silicon and slag were determined at 1600 °C for calcium silicate slags with a CaO/SiC>2 ratio between 0.65 and 1.3. An almost horizontal linear trend was found for the distribution of boron between silicon and slag, and the borate capacity was found to follow the relationln(CB0, ) = 30.8 + 2.96-V (1)where V\s the CaO/SiCh mass ratio within the range of the experiments.IntroductionSolar grade silicon feedstock contributes significantly to the total cost and energy required to make crystalline silicon solar cells. A less expensive and less energy requiring method of solar grade silicon production is therefore needed in order to make crystalline silicon solar cells more viable as an energy source. Silicon is an abundant element and the manufacturing cost of solar grade silicon is therefore mainly determined by costs related to purification of metallurgical grade silicon. The Siemens process is the most common process today, but it is an expensive and highly energy requiring process that gives silicon with a higher purity than is needed for crystalline silicon solar cells. A cheaper and less energy requiring method for production of solar grade silicon can either be achieved by modifying the Siemens process or by using a new production method. Purification of metallurgical grade silicon through a metallurgical route is a promising method that is already in use industrially. It has however proven to be hard to lower the boron content to 0.3 mg/kg or less, which is the requirement for most p-type crystalline silicon solar cell manufacturers. Slag refining is seen as one of the most promising approaches that can be used to bring down the boron content to the required level, but there is not much data on how boron is distributed between silicon and binary calcium silicate slags [1-4]. The distribution of boron between silicon and calcium silicate slags at 1600 °C has been studied in this work, and the obtained data has been used to calculate the borate capacity of binary calcium silicate slags."

Jan 1, 2012

By C. H. Jr. Herty

ALMOST every metallurgist who has given the Howe Memorial Lecture has had a personal contact with the distinguished gentleman to whose honor this hour is devoted. Unfortunately for me, such personal contacts were not possible. However, in the preparation of a thesis on the open-hearth process, one of my earliest tasks was to make a survey of the literature, and it was from Professor Howe's Metallurgy of Iron and Steel that I drew a number of references to previous work which formed the foundation for my reading. In his volume there is such a complete exposition of the then current thought on the subject of slags and on their role in the elimination of phosphorus from steel that I feel no hesitation in discussing in this Howe Lecture the subject of "Slag Control." In the present era of close specification, the drive for uniformity of product, and the close inspection of the product and of the cost sheet, the utmost efforts must be made to control the steelmaking variables to the best advantage of the steel producer. One of the major variables is the slag in the furnace and its effect upon the composition and quality of the metal. What advantages are to be gained from slag control? In the broad sense the advantages must be tremendous, because the very foundations of good steel melting are based on "shaping up" the slag to a point where, with proper temperature, the heat is ready for the final additions. Every melter works toward these ends through his experience with innumerable heats of steel. The elimination of undesirable constituents such as phosphorus and sulphur is entirely a matter of slag composition and physical nature, a point well known for over half a century. The role played by the slag in assisting in proper heat transfer from roof and flame to the steel has been equally well known. In more recent years there has come the problem of oxygen control in the more accurate gaug-ing of additions for making high-grade rimmed steel for the new strip mills, and in the deoxidizing additions for grain-size control and cleanli-ness of forging steels, both carbon and alloy. In this problem the oxidiz-ing characteristics of the slag are of prime importance.

Jan 1, 1940

By J. D. Grace

Screening by centrifugal force is a unique subject, for all vibrating screens, with but one exception, depend on gravity alone to pass material through a sizing mesh or screen cloth. Centrifugal screening is one of the greatest advancements made in screening since the development of vibrating screens. It makes possible sizing in a range previously im-practical by mechanical methods. The centrifugal screen is specially designed for fine sizing from No. 4 separations to finer than No. 100 separations. Centrifugal force provides a positive control of factors that make fine particle separation practical and effective as opposed to gravity which is a fixed force acting only in a fixed direction, The centrifugal screen provides a control of the force of material against the screening surface, and also controls the distance of departure of the material from the surface and its rate of return. The centrifugal screen has a rotating drum that becomes a natural fan blowing air outward through the material being screened and carrying float dust and fines through the apertures with it. Screening by centrifugal force is an unique subject, for with the exception of only one vibrating screen presently on the market, all vibrating screens depend upon gravity to pass material through a sizing mesh or screen cloth. This one screen that sizes by centrifugal force and utilizes gravity only to convey material along the screen, is the Symons V-Screen. The requirements of the industrial minerals industry to meet ever-increasing stringent fine sizing specifications by a practical mechanical method accentuates the weakness of gravity, a fixed force acting in a fixed direction, as a prime force for fine sizing. It was apparent a force other than gravity was needed. This led to the development of a centrifugal screen to meet modern demands for practical fine sizing operations. Gyratory-type screens in use today were originally designed in a day when a 1/4-in. separation was normally considered fine sizing and 1/8-in. separations were extremely fine sizing. Although gyratory-type screens are sometimes used for separating below 1/8-in., they are not practical screens for this purpose. They were not designed to do this type of work. A growing demand for a practical means of making positive mechanical separations in a range of from 1/8 in. downward led to the development of the vibrating screen. These screens utilize higher speeds and lower amplitudes of vibration than

Jan 1, 1967

By Walter C. Lawson

THE first plans were made in 1930 for the mining by open-pit methods of the low-grade disseminated ore body now known as the Morenci open pit. It was not until 1937, however, that final plans were completed and the decision reached to go ahead with the actual development. Many advances were made in open-pit mining equipment during that period of seven years, therefore the ways and means of attack actually used were very different from those originally contemplated. Diesel-operated bulldozers, big trucks, full-revolving electric shovels and electric churn drills constitute the major equipment finally purchased for this modern stripping operation. Neither the bulldozers nor the big trucks were considered in the early operating plans, for at that time bulldozers had not been used in mining operations and the trucks as yet were undesigned. The full-revolving shovel and the churn drills were not new developments in open-pit equipment, but both had undergone remarkable manufacturing transition, emerging far more efficient and far more dependable than their predecessors. Even the ordinary drilling steel had been fundamentally changed. It was now threaded so that the dulled cutting bits could be detached and replaced, thus eliminating the costly transportation of long bars to the drill shop for resharpening. The decision to use trucks in the preliminary stripping operations was based on the desirability of this type of transportation to economically prepare the pit for rail haulage, coupled with the success that the contractors had had with them on other big excavation jobs. There are at present no plans for the use of trucks beyond the preliminary work, inasmuch as rail haulage will give lower costs after roadbeds and benches are once established. For many years to come, both ore and waste haulage will be over favorable grades. The average length of ore haul between the pit and an assembly yard will be about two miles. From there the crushers will be 1 1/3 miles with a connecting track grade of 0.4 per cent. The upper ore benches of the pit will be reached from the yard by a series of four switchbacks over a ruling grade of 4.0 per cent compensated for curvature. Tracks to the dumps will be on 0.2 per cent grades.

Jan 1, 1938

By Walter C. Lawson

The first plans were made in 1930 for the mining by open-pit methods of the low-grade disseminated ore body now known as the Morenci open pit. It was not until 1937, however, that final plans were completed and the decision reached to go ahead with the actual development. Many advances were made in open-pit mining equipment during that period of seven years, therefore the ways and means of attack actually used were very different from those originally contemplated. Diesel-operated bulldozers, big trucks, full-revolving electric shovels and electric churn drills constitute the major equipment finally purchased for this modern stripping operation. Neither the bulldozers nor the big trucks were considered in the early operating plans, for at that time bulldozers had not been used in mining operations and the trucks as yet were undesigned. The full-revolving shovel and the churn drills were not new developments in open-pit equipment, but both had undergone remarkable manufacturing transition, emerging far more efficient and far more dependable than their predecessors. Even the ordinary drilling steel had been fundamentally changed. It was now threaded so that the dulled cutting bits could be detached and replaced, thus eliminating the costly transportation of long bars to the drill shop for resharpening. The decision to use trucks in the preliminary stripping operations was based on the desirability of this type of transportation to economically prepare the pit for rail haulage, coupled with the success that the contractors had had with them on other big excavation jobs. There are at present no plans for the use of trucks beyond the preliminary work, inasmuch as rail haulage will give lower costs after roadbeds and benches are once established. For many years to come, both ore and waste haulage will be over favorable grades. The average length of ore haul between the pit and an assembly yard will be about two miles. From there the crushers will be 1? miles with a connecting track grade of 0.4 per cent. The upper ore benches of the pit will be reached from the yard by a series of four switchbacks over a ruling grade of 4.0 per cent compensated for curvature. Tracks to the dumps will be on 0.2 per cent grades.

Jan 1, 1940

By Walter C. Lawson

The first plans were made in 1930 for the mining by open-pit methods of the low-grade disseminated ore body now known as the Morenci open pit. It was not until 1937, however, that final plans were completed and the decision reached to go ahead with the actual development. Many advances were made in open-pit mining equipment during that period of seven years, therefore the ways and means of attack actually used were very different from those originally contemplated. Diesel-operated bulldozers, big trucks, full-revolving electric shovels and electric churn drills constitute the major equipment finally purchased for this modern stripping operation. Neither the bulldozers nor the big trucks were considered in the early operating plans, for at that time bulldozers had not been used in mining operations and the trucks as yet were undesigned. The full-revolving shovel and the churn drills were not new developments in open-pit equipment, but both had undergone remarkable manufacturing transition, emerging far more efficient and far more dependable than their predecessors. Even the ordinary drilling steel had been fundamentally changed. It was now threaded so that the dulled cutting bits could be detached and replaced, thus eliminating the costly transportation of long bars to the drill shop for resharpening. The decision to use trucks in the preliminary stripping operations was based on the desirability of this type of transportation to economically prepare the pit for rail haulage, coupled with the success that the contractors had had with them on other big excavation jobs. There are at present no plans for the use of trucks beyond the preliminary work, inasmuch as rail haulage will give lower costs after roadbeds and benches are once established. For many years to come, both ore and waste haulage will be over favorable grades. The average length of ore haul between the pit and an assembly yard will be about two miles. From there the crushers will be 1? miles with a connecting track grade of 0.4 per cent. The upper ore benches of the pit will be reached from the yard by a series of four switchbacks over a ruling grade of 4.0 per cent compensated for curvature. Tracks to the dumps will be on 0.2 per cent grades.

Jan 1, 1940

By G. F. Bolling

Single crystals of each metal were deformed at 77°K and heated at constant rates, variously in the range 0.125" to 4o°Kper min from 77" to -390oK, while being monitored in an X-ray diffractometer. Changes in diffraction-peak heights and line breadths were used to ascertain the temperature ranges of recrystalliza-tion. The results were subjected to the analysis of nicholas' in order to obtain the rate-controlling activation energies,Q. In this analysis no recourse to a separate and distinct nucleation stage is required and the results of studying recrystallization proved consistent with the hypothesis of a constant number of nuclei or equivalent hypotheses. The values Pb = 5.5 ± 0.5 keal per mole Zn ~ 7.5 Sn - 5 Bi - 9. 5 correspond for lead, zinc, and tin to activation energies obtained elsewhere for grain boundary migration, and for bismuth and lead to previous studies of re-crystallization by Barrett.6 This correlation allows the conclusions that interference from recovery was minimal and that the observed recrystallization rates in these pure metals are effectively governed by grain boundary migration. Good agreement was not found between the results of this kind of study in zone-refined aluminum and previous work; and supplementary isothermral experiments involving hardness tests and metallography did not resolve the discrepancy. Nevertheless, at least a range,Q = 11.5 ± 2 keal per mole, can be assigned to the activation energy for boundary migration in aluminum. An experimental study of one aspect of the recrystallization process is presented here for four metals of different crystal structure. The metals chosen for study were all zone-refined to reduce impurity effects, but the attendant high purity presented a difficulty. For any reasonably high driving force a "re-crystallization temperature", TR, is in the range of 0.25 T,, where T, is the absolute melting point, and study was therefore restricted to lower temperatures. An X-ray technique under constant heating-rate conditions adequate above 90°K was devised for the study; in consequence, a newer type of analysis following Nicholas1 had to be used to obtain quantitative information about activation energies. The standard methods of studying recrystallization have involved the comparable analyses of Johnson and Mehl2 and Avrami3 which are reviewed by Burke and Turnbull.* The general analysis4 which is applied only to isothermal studies using any of various investigative techniques states:

Jan 1, 1968

By J. G. Mieczaniec

"A key element for a successful mining operation is the grinding circuit. It must be reliable, maintainable and must perform to or above design capacities for 95% of the time. Once chosen and installed major modifications are either prohibitive or very expensive. The selection of mills and drive system is probably the single most important decision made within the concentrator complex.Economic studies revealed that the optimum expansion for Lornex was a 68070 increase in plant throughput. This indicated that the new mill would have to be larger than the existing 32-foot mills.The Lornex ore has a wide range of hardness which has a great influence on mill throughput (Table 1). To smooth out the fluctuations, a blending program ha s always been in effect at the mine, coupled with ball charge control for the primary mills. As can be appreciated, an optimum balance is difficult to achieve. A sudden change to so ft ore with a high ball charge puts the mill into jeopardy with a constant speed drive.The blending philosophy would continue after the expansion, but with the addition o f a second primary crusher, it was envisaged to have the new mill process harder ore to maintain production targets. In theory, the new mill would have a proportionally larger ball charge than the existing mills.This scheme makes the new mill vulnerable for processing so ft ore for a fixed speed mill. Thus, variable speed seemed an attractive option.In early 1979 prominent mill manufacturers were invited to submit proposals for the new mill. Fixed and variable speed mills were to be considered with mill size ranging from 32-foot to 36-foot diameter. The proposals were to include the drive, ball charge, % critical speed, couplings, gears, etc. - the complete package. The recommendations were variable with most manufacturers submitting several alternatives. Recommended mill speed varied from 68% to 78% critical. The concept of variable speed was becoming more attractive, Lornex ultimately decided on a twin DC motor drive system for a 34-foot diameter mill.After start-up it was discovered that best throughput occurred at 78% mill critical speed or top speed of the drive motors. The motor speed range was adjusted upward from 186 to 200 rpm. Today the mills operate at 79% critical or a motor speed o f 193.5 rpm.Clearly the selection of the variable speed mill allowed the flexibility to optimize throughput."

Jan 1, 1985

By Donald Roberts

"Parameters f or design and development of an emergency hoist system (Fig. I) were submitted to Timberland Equipment Limited of Woodstock, Ontario by the Potash Corporation of Saskatchewan Mining Limited.The unit is the first of its kind in Canada. Not only does it comply with the province of Saskatchewan's mining regulations, but has the added advantage of being completely mobile and self-contained.As well as being useful in the mining industry, the mobile hoist unit could be used in other emergency situations such as rescuing people trapped in wells.JustificationRevisions to the Mines Regulations under Section 13 of the Occupational Health and Safety Act, 1977, of the Province of Saskatchewan stipulate as follows:"" Section 410 .04(4) The Mine Employer shall make adequate provision at every mine where any worker is hoisted in a shaft not equipped with a manway to enable an y such worker trapped in a conveyance in the shaft to be rescued . "" It was not possible to equip the shafts at PCS Mining' s Divisions with "" manways"" and therefore an alternative was required.BackgroundThe Potash Corporation of Saskatchewan Mining Limited, a subsidiary of the Potash Corporation of Saskatchewan, operates four potash mines. Of these, three, Cory, Rocanville and Lanigan Divisions are wholly owned while the fourth, Allan Division, is 40% owned by Kidd Creek Mines Ltd., but managed by PCS Mining. The four underground operations all have a service and production shaft.From 1979 to 1981 the PCS Mining Division, along with Central Canada Potash, were developing an idea to use the existing ground-mounted timberland hoist at Lanigan as an emergency hoist. This hoist was used in the past for rope-up work at both Rocanville and Lanigan and other potash mine s. The Department of Labour at this time had concerns about the time it would take to load, t ran sport and re-install the hoist on a foundation when needed for an emergency. Weight and size made this particular unit very cumbersome for transporting.In addition, the speed at which this hoist operates is too slow for rescue work. When the Department of Labour expressed concern that this unit would be unsuitable for these rea sons, a search for a suitable unit was initiated.The project responsibility for procuring an emergency hoist for the Potash Corporation of Saskatchewan Mining Limited was assigned to the author, a shaft/ hoist specialist a t PCS Mining."

Jan 1, 1986

By Jerome Apt

This report presents the methods and results performed pursuant to the U. S. Bureau of Mines contract entitled "Noise Abatement in Mining Machinery," Number H0122054. 2.1 Background Until the Congress of the United States created and passed Public Law 91-173, the Federal Coal Mine Health and Safety Act of 1969, there were no directly-applicable standards for noise exposure for underground coal miners.1 Section 206 of this law, approved December 30, 1969, provided for standards of noise to be applicable to each coal mine. It is as follows:

Jan 1, 1975

By J. A. Bartol

A survey was made of accident data and operating practices related to overloading and uneven load distribution on haulage trucks in noncoal open pit mines. Safety and economic aspects were analyzed. A bibliography of the literature was prepared. Review was made of available or projected systems for weighing or load indicating that might be applied to haulage trucks. A model specification was prepared for an overload detection system. Several promising systems for overload detection were identified. One was installed and tested briefly in a 170-ton rear dump truck in a copper surface mine.

Jan 1, 1982

By W. C. Blanchard

Time Domain Reflectometry (TDR) is a remote sensing technique using active backscatter. This technique is applicable to the testing for faults and multiple partial faults on cable. The battery operated hardware developed on this con¬tract has tailored this technique for testing of mining equipment trailing electrical cables. The processing of-t-he back-scatter is accomplished using a microprocessor. The visual output from the hardware to the operator is; the type, magnitude and distance to the cable fault in a numerical format. This greatly simplifys the use of this techniques for the operator.

Jan 1, 1980

By A. Erickson

The effectiveness of a loader-mounted fan on diesel vehicles combined with natural convection for ventilation of a dead heading (the patented Janelid system) was investigated experimentally. The results were obtained using CO2 as a tracer gas in a 1/4 scale model heading. Buoyant forces were scaled to establish similarity with full scale. For a loader moving in a typical load-haul-dump cycle, the loader-mounted fan reduced the tracer gas concentration by 26 percent compared with a reduction of 32 percent for a jet fan of four times the flow capacity.

Jan 1, 1981

By Joel N. Van Sant

An investigation was conducted to study possible sources of Utah refractory and structural clays that could be used for the manufacture of refractories and light or buff burning heavy-clay products. A field study was made and the clay samples tested to determine their firing characteristics. Results of the Bureau's work indicate many small noncommercial deposits of hypogenic clay occur in igneous rocks. Commercial hypogenic deposits are mostly halloysite clay developed by hydrothermal replacement of limestone. The high firing shrinkage of halloysite precludes its use as a refractory, however, halloysite produced at the Dragon Mine south of Eureka, is used for making oil catalysts. Clays and shales suitable for low heat duty refractory products are found in the Manning Canyon shale, in shales associated with coal bearing rocks, and in the Dakota formation. Some of the clays from the Dakota formation are also suitable for high-duty refractory products.

Jan 1, 1964

By John H. Johnson

A study of mine air quality was conducted using the latest advanced continuous monitoring instruments. An overview of the various interacting variables in the mine that affect air quality is presented. One effort involves the evaluation of portable instruments, the development of measurement techniques, sample analysis procedures and computer programs for statistical analysis of measurement data, and the application of the instruments and techniques to the measurement of the concentrations of CO, CO2, NO, NO2 and particulate matter in a lead and a copper underground mine. A second effort involves the first application of the Mine Air Monitoring Laboratory (MAML), a mobile trailer containing laboratory type instruments, sampling and data systems for the measurement of CO, CO2, NO, NO2 and particulate matter. The data from the MAML for blasting and for operating diesel equipment are analyzed and presented in various plots.

Jan 1, 1977

By Bruce E. Stauffer

The report recommends criteria for the design of safe surface mine haulage roads. Information relevant to road design at surface mine sites delineates vertical and horizontal alignment; subbase and surface materials; drainage; cross-slope, superelevation; runaway vehicle protection; and road and vehicle maintenance criteria. An appendix Is included which details the study methods used in compiling the final report information. A bibliography following the main text lists literature referenced for the report data and which is available as a valuable tool for use by individuals involved in haul road design.

Jan 1, 1976

By R. T. Hukki

The paper describes a two-stage industrial hydraulic classification system including hydrocyclones for primary classification and newly developed cone classifiers for secondary classification. Performance data based on large scale grinding and classification tests are presented.

Jan 1, 1981