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By Robert Benedetti

This paper describes various mitigation methods in order to reduce the maximum acceleration of the floorboard of hulled vehicles when explosive charges buried in water saturated sand were detonated beneath them. The effects on floorboard acceleration of adding a vehicle hull, several types of floorboard bracing, the use of foam to fill the gap between the floorboard and hull, and the use of foam to isolate the floorboard from the hull have been investigated. Small scale testing was conducted, which used bar magnet velocity gages to measure the velocity as a function of time of the center of the floorboard, directly over the charge, where the acceleration was expected to be greatest.

Jan 1, 2012

By Stefan Mutl

By the term sorting one understands the separation of a material mixture into two or several products according to different material characteristics in the preparation technology. The oldest sorting procedure, the handpicking, is less and less used to separate different material mixtures because of the considerable personnel expenditure and the strict hygienic regulations at the workplaces in Europe. In general, the manual assortment is able to solve separation tasks, which could not be solved by machines so far. The picking is one of the most selective processing methods. However, the progress in the computer and sensor engineering today makes the creation of automatic picking devices possible, whose efficiency goes far beyond the possibilities of handpicking. Therefore in the future automatic picking will not only be applied to already common applications like the waste glass assortment by colour, but also to the assortment of complex composed material mixtures e.g. old shreddered cars. Thus, the automatic picking, supported by high performance computer systems and new sensor technology, gains more and more significance within many applications of waste processing. However, in order to apply automatic sorting procedures for different material streams within recycling processes, a substantial research and development need still is existing. The desire of the users is to sort more extensively in order to achieve products with bigger material varieties, In addition, the requirement of the accuracy of recognizing and sorting out of single grains rises, This lecture illustrates the procedure of the hand picking before it was employed in waste processing. Thus, a renaissance of a long forgotten method is happening in terms of today's state of the art procedure "automatic picking". Possible technologies, fields of application and future potentials of this technology are pointed out.

Jan 1, 2003

By J. Serra, M. Turpin, R. Alberny

A new method is proposed to obtain automatically an unbiased estimate of the interdendritic spacing A. It is shown that the structure can be built by a random distribution of a rectangular basic unit. The usual definition of the interdendritic spacing yields a value 1 which, coupled with A, gives the shape of the basic rectangular unit. A study of the relationship between dendrite arm spacing and solidification rate was conducted as a part of a research program on dendritic solidification. For any comparison between theory and experiments to be meaningful, it is necessary to measure reproducible and clearly defined spacings. Fig. 1 shows clearly that even in a fairly simple structure such measurements are difficult. if we compare photos (a) and (b), we can hardly assess which one shows the larger spacing. Moreover, the quantity to be measured can be defined in several ways. On a small scale, dendrites seem to be distributed in a very regular and ordered way. However, on a larger scale, this regularity no longer exists. The usual way to measure spacings is to pick up some rows of dendrite stalks; such measurements are obviously biased since less orderly regions are not taken into account. A more objective method is to section the picture with randomly oriented straight lines and average the measured interdendritic spacings. The purpose of this paper is to show that such measurements, which can be conducted automatically, yield objective and reproducible results which are directly related to characteristic features of the dendritic structure. I) THEORETICAL ANALYSIS 1-1) Mathematical Morphology and Function of Co-variance. Matheronl and Serra2 enlarced- the definition and geometrical meaning of the notion of covariance to encompass problems in mathematical morphology. A brief review of part of their theory can be stated as follows. Let A' be an isolated particle, and let us consider a group of two scanning points h is the vector joinlng these points, h its modulus, and a its direction. Let us also define a boolean function, k(x), whose value is 1 if x lies inside the particle and 0 if it 1s outside. The total number of events in which both points are inside A' IS the covariance Ii',(h): is the measure of the intersection of A' with the particle ALh obtained by translating A' of -h Obviously K,(O) is the volume of the particle A', or its area if A' is a two-dimensional body. The average value of K,(h), when the direction of a vector h of constant modulus is rotated, is: An important property of the covariance is illustrated on Fig. 2: if the shape of a particle shows some regularity along a direction a, K,(h) generally presents a maximum. We now consider a group A, made of many particles A' distributed in space; then k(x) is taken as the realization of a stationary random f~nction.~ The volume fraction (or fraction of area if the problem is two-dimensional) occupied by A equals the average value q of k(x): meaning "average value of"). We also replace

Jan 1, 1970

By John McMorran

An open pit mine design system should have the characteristics of being flexible, versatile, and simple. All of these characteristics are necessary for producing a dynamic mine design. In other words, a design that can be improved, updated, and implemented. Flexibility is an important characteristic due to changing times. For example, the effects of a changing economy, increased knowledge of the mineral deposit, or improvements in mining technology can result in a considerable, if not a complete change in the long range mining plans. Since the short range mining plans are based on the long range mining plans, they will-also be effected. Also, it is very important to validate the information used in the design or the design itself. This means the system should have the flexibility of being able, not only to detect, but to correct errors. Versatility is another important characteristic of a mine design system due to the wide range of situations that may appear. First, a design system must be able to handle both long and short term planning. This is necessary because of the variability in the definition of a time range. Second, a design system must be able to handle different types of deposits. Special emphasis must be placed on this issue, because many deposits, if not the majority, do not fit predefined categories such as bedded, massive, or roll-front, etc . . . Furthermore, the true test of the versatility of a design system is not only the ability to create an ultimate design but also to schedule sequences for this design. Thus, the versatility of being capable to design with a variety of time ranges, variety of deposit types, and scheduling are all important characteristics of the design system.

Jan 1, 1982

And it takes more than good organisation. You may read or heard this poignant reflection: We tried hard, but it seemed that every time we were beginning to form up in teams we would be reorganised. I was to learn later in life that we tend to meet any new situation by re-organising, and a wonderful method this is for creating the illusion of progress while producing confusion, inefficiency, and demoralisation This was written by the Roman Gaius Petronius in AD65. How much have things changed in nearly 2,000 years? What then does it take besides the fundamentals and good organisation to build a successful career in a successful organisation? I'm prepared to venture a list of what I'll'call Tips for Young Professionals. If you've got what it takes, and apply these, I think that you'll gain a great deal of satisfaction from your career, even if you don't reach the distant target each of you should have in mind now. So settle back in an advice-receiving mode, and please forgive me if I come across as a master of the bleedin' obvious, as Basil once accused his wife Sybil of being in the unforgettable Fawlty Towers.

Jan 1, 1990

By R. N. Roby

"INTRODUCTION A preliminary examination of the Green Monster and Benich copper prospects was made by engineers E. W. Newnan and George N. Bennett, of the Bureau of Mines, on December 13, 1943. In an unpublished report, it was stated that certain geologic features appeared to be similar to those associated with the copper deposits of the nearby Butte district. On these premises, a preliminary diamond-drilling program was recommended to explore 300 to 400 feet below the mineralized outcrops for the possible presence of a sulfide enrichment zone. In accordance with that recommendation, three holes were drilled. This report presents the data provided by that preliminary drilling exploration.ACKNOWLEDGMENTSIn its program of exploration of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell D. Moon, chief, conducts preliminary exminations, perform the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyses samples and performs beneficiation tests.The field work on the Bull Run exploration project was supervised byE. W. Newman engineer in charge of the Helena field office. The chemical analyses and assays included in this report were performed under the direction of A. C. Rice, acting engineer in charge, Bureau of Minos Rare and Precious Metals Experiment Station at Reno, Nev. The diamond-drill cores were logged by geologists of the Federal Geological Survey."

Mar 1, 1947

R. H. THURSTON, Cornell University, Ithaca, N. Y. (communication to the Secretary): The " tri-axial diagram" was, I think, first employed by me in the work of the " U. 8. Board Appointed to Test Iron, Steel and Other Metals." A model was exhibited to the American Association for the Advancement of Science, and the diagram was first published, and the model described, in a paper presented to the same society at its Nashville meeting in 1877." The problem then presented to its inventor was to find a method of planning a research involving proportions of ternary compositions in such manner that, a limited number of such compositions being tested, the results should give the law of variation in the physical properties of all possible combinations of the three elements, and the actual numerical values of such as were important to the investigator. The investigation of the binary alloys, copper and tin, copper and zinc, and tin and zinc, had been completed and satisfactorily discussed, employing the usual bi-axial diagram, of which the ordinates represented the one, and the abscissæ the other, of the characteristic properties to be studied, the composition being commonly indicated by the abscissæ. In these cases it was easy to ascertain, by the study of a limited number of compounds, the law of variation in strength, ductility, etc., with composition; but, for a long time, the ternary alloys were not attacked, because no simple and satisfactory method presented itself of securing results significant for the whole field by the investigation of a comparatively small number of alloys. The tri-axial diagram was finally hit upon as a means of representing and interpreting results, and researches were at once begun, and in due time satisfactorily completed.

Jan 1, 1899

This paper presents the results of research aimed at proposing new solutions in the area of belt conveyor elements. Many factors, such as energy consumption costs, and operating costs of belt conveyor elements, including belts, idlers and drives have an impact on the operational costs of conveyors. The paper presents special tests of new materials for the bottom cover of an energy-saving belt conveyor, which decrease rolling resistance. It also presents large-scale in-situ tests of a high-output belt conveyor for the purpose of simultaneous measurements of various types of conveyor belts (standard vs several energysaving types) under typical operating conditions of a lignite surface mine. Improvements in materials used for the bottom belt covers, supported by specially developed comprehensive tests of the new types of belts have provided valuable results of various proposed solutions. Since the tests of belts were done at exactly the same time and in the same operating conditions, direct comparison of the results is valid and should lead to a substantial decrease in the conveyors? drives? energy consumption, which will improve the effectiveness of belt transport and minimize its negative influence on the environment.

Aug 1, 2013

By T D. H McGrath, O Baker, W P. Staunton, C Ypelaan

"The carbon-in-pulp process has been used extensively in the gold industry since the late 1970s to recovery leached gold from solution. Despite more than 30 years of experience in operating carbon circuits, average gold solution loss has remained at an average of 0.02–0.03 ppm (mg/L), higher than the ‘best practice’ target of 0.01 ppm.Process modelling, such as SIMCIL developed by the Curtin Gold Technology Group (GTG), can provide information on optimum set points; however, manual control of the circuit limits the potential benefits.An automated carbon measurement device, the Scout Carbon Meter, has been developed to allow for automation of carbon concentration measurement, and automated control of the carbon transfer pumps. This paper describes the results from the evaluation of the first two prototypes of the meter.Citation:Staunton, W P, McGrath, T D H, Ypelaan, C, Baker, O and Eksteen, J J, 2016. Optimising Carbon Management - Increasing Gold Recovery and Decreasing Costs with the Carbon Scout, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 225–228 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By H. C. Van Der Merwe

In the 21st century, dynamic, accurate digital 3-D geological models are essential to the pursuit of safe, efficient and profitable mining. This is particularly true for the deep-level underground mines in South Africa. The Sirovision® solution is a collaboration project between the Australian CSIRO (Commonwealth Scientific and Industrial Research Organisation), Datamine Software Ltd. and AngloGold Ashanti Ltd (AGA). The purpose of the project is to provide a fully integrated digital rock face imaging, geological mapping and modelling system for the AGA gold mining operations. The CSIRO-developed Sirovision® Stereo Camera Rig (SCR) consists of two digital cameras, alighting system, a laser guidance system and image processing software. The imaging system works on the principles of photogrammetry, i.e. overlaying of two 2-D images with a central focus point, with mathematical algorithms extracting 3-D information from the 2-D image pair. The output from matching several image pairs is a computer-generated, full 3-D, virtual copy of the mining excavation. The image resolution and relief ares of sufficient quality to distinguish different rock types and structural contacts. Functionality within Datamine Studio3 is used to add geological intelligence to the 3-D images provided by Sirovision®. The geologist identifies and ?draws? lines representing geological features directly onto the image. By utilizing the inherent ?topography? of the 3-D image, the software is able to convert the lines into 3-D surfaces, ready for use in the 3-D geological model. Subsequent to promising underground test results from AGA?s Sunrise Dam Gold Mine (SDGM) in Australia and other mining operations worldwide, it was decided to test the Sirovision® system in the South African deep-level gold mines. The first underground tests at Moab Khotsong Mine began in January 2009. The objectives of these tests entailed the capturing of 3-D images of selected development ends, mapping of geological features onto the 3-D images and integration of the mapping data with the 3-D geological model. Some downsides have cropped up during the feasibility testing, related to practicality of the SCR for acquisition of 3-Dimagery in the deep-level underground operating environment. These constraints will have to be addressed prior to operational implementation. Facing such difficulties is not unusual when attempting to implement new technology in such a challenging working environment and testwork is still in progress at the mine in order to prove the concept of using this technology in a Witwatersrand underground gold mine. The great advantage of the Sirovision® solution is that it offers the geologist the opportunity to work remotely on a 3-D virtual copy of a mining excavation, without the heat, humidity, hazards and time constraints associated with physical mapping in an underground workplace.

Jan 1, 2009

Jan 1, 1969

By Hae-Moon Choi, Sang-Don Lee, Hee Soon Shin, Choon Sunwo, Chang-Ha Ryu, Hyun-Koo Lee

Building tunnels means dealing with what rock is encountered. Relocation of the site of the underground structure is rarely possible. Tunneling engineers and miners have to cope with the quality of the rock mass as it is. Different tunneling philosophies and different rock classification methods have been developed in various countries. Most of the rock classification methods are based on the response of the rock mass to the excavation. Tunnel support requirements could be assessed analytically, supplemented by rock mass classification predictions, and verified by measurements during construction. Rock mass classifications on their own should only be used for preliminary, planning purposes and not for final tunnel support. Design of blast pattern in tunneling projects in Korea is also for the most part prepared according to the general rock classification methods such as RMR or Q. It, however, does not take into account the blast performance, and as a consequence, produce poor blasting results. In this paper, the methods of general rock classification and blast design for tunnel excavation in Korea are reviewed, and efforts to develop a new classification method, reflecting the blasting performance, are presented. Copyright ©

Jan 1, 2004

By Nguyen G. H, Graham J

A laboratory-scale fluidised-bed roaster has been used to examine the effect of temperature and duration of roast on the morphology of the calcine produced from a pyritic gold-bearing concentrate. Two mechanisms of oxidation, which depend on the roasting temperature, have been identified. For samples roasted below 550°C, direct oxidation of the sulphide occurred to form hematite with a porous fine-grained concentrically-layered texture. The surface area of the calcine increased with an increase in roasting temperature in the range 400 to 500°C. For samples roasted above 550°C, the first reaction was the evolution of sulphur vapour to produce pyrrhotite, which underwent increasing grain growth as the roasting temperature was increased. This had the effect of decreasing the surface area of the calcine. The pyrrhotite was subsequently oxidised to produce hematite.Leaching studies using cyanide solution indicated that gold extraction around 95 per cent was achieved at temperatures of 500°C and above, with optimum extraction, taking into account rate and cyanide consumption in the range 550 - 700°C. Hence recovery did not decrease with decrease in surface area of the calcine. Observed gold in leached calcines was mainly enclosed in thin oxide walls of the hematite, with minor quantities enclosed in quartz and silicate minerals.

Jan 1, 1995

By Gene O. Cowie

"Zinc, which once enjoyed an unchallenged position in the field of decorative applications, has lost a substantial share of its markets to other materials, particularly plastics. This turn of events has led the zinc industry to explore new market areas, particularly those applications where the engineering properties of zinc can be utilized. This paper gives an overview of the zinc industry's efforts to develop the data base and product development technology which have enabled zinc alloys to emerge as engineering materials. It also indicates those areas in which the research facilities of the zinc industry must be employed to ensure that zinc alloys keep pace with developments in competitive materials and processes.The Materials RevolutionThe development and utilization of new materials and manufacturing processes progressed for centuries by evolution. Recently it erupted into a revolution, which may become as significant as the industrial revolution. The materials revolution has impacted upon many industries, but none has been affected more traumatically than the North American automotive industry. The plight of that industry is of great importance to us because their problems have, to a great degree, become problems to the zinc industry.Much of the impetus behind the automotive trauma came from the battery of motor vehicle regulations promulgated by the United States government in the 1970s. These regulations required that the efficiency of passenger cars, in terms of miles per gallon, be approximately doubled in ten years. In view of the fact that major changes in the automotive world require three years of lead time to implement, the industry was left with only seven years to perform the task. The automotive industry was simultaneously required to make progress in other areas, such as reduced emissions, reduced cost of repairs and increased levels of occupant safety. These added demands not only diverted some of the available resources away from efficiency goals, they often ran in direct conflict. For example, when you are required to provide a front bumper which will absorb the energy of a 5-mile -per-hour barrier collision, you must add both hardware and structure to the vehicle. This adds weight, and increased weight reduces miles per gallon."

Jan 1, 1983

SOUTHERN CALIFORNIA SECTION Executive Committee SEELEY W. MUDD, Chairman. C. COLCOCK JONES, Vice-Chairman. FREDERICK J. H. MERRILL, Secretary-Treasurer, 631 Higgins. Bldg., Los Angeles, Cal. RALPH ARNOLD A. B. CARPENTER A. B. W. HODGES WILLIAM F. STAUNTON The third meeting of this winter season tool: place in a private dining room of the Sierra Madre Club in Los Angeles on Feb. 1, 1916, at 6:30 p.m., 22 members and guests being present. In the absence of the Chairman, S. W. Mudd, the Vice-Chairman, C. Colcock Jones, presided. After an enjoyable dinner the meeting was called to order, and the first paper by Ralph Arnold on Conservation of Oil and Gas in the Americas was read by the Secretary. W. F. Staunton then read an important paper on The Influence of California Oil on the Mining Industry of the West. In this he touched upon the uses of oil as a fuel for generating power, especially in connection with the Diesel engine. This paper was discussed it some length by J. F. Mitchell-Roberts, R. B. Moran, F. H. Asbury and L. D. Godshall. The Chair then introduced Robert B. Moran of the California State Mining Bureau, Deputy Supervisor of Gas and Oil, for the' Los Angeles . District, who addressed the meeting on the work of his department. The meeting concluded with A. B. Carpenter's reading of a paper on The California Gasoline Industry by W. R.. Hamilton, Manager of the Ventura Refining Co. F. J. H. MERRILL, Secretary. ,

Jan 4, 1916

By Sup Hong

"Lifting riser in deep-seabed mining (DSM) is exposed to acute and chronic stresses of materials, whose yield will result in the most critical loss of total mining system. For freehanging riser (FHR), the axial vibration and local bending of riser may produce acute stresses, in the meanwhile, vortex-induced vibration (VIV) in relative current, friction and collisions of solid particles with inner-wall, and material corrosion in seawater are representative causes of chronic stresses. The chronical stresses bring about fatigue failure or abrupt failure by material loss. Hydraulic lifting is effective and promising for transportation of minerals, however, ecofriendly treatment of operating seawater is an unease hurdle to come over. Sizing of riser section confronts multi-directional problems, i.e. safety of slurry transportation (flow assurance), material safety of riser (wall thickness), seawater treatment on board, etc.A free-standing riser (FSR) might exclude a part of design problems of free-hanging riser and give a way to sustainable mining. FSR stands vertically by means of sub-buoyancy part(s). The top of FSR emerges above sea surface and is connected with mining platform through jumper line (supported by external yoke). Total amount of sub-buoyancy and location(s) have to be carefully determined in viewpoints of dynamics of FSI (fluidstructure interaction) in waves and currents. The concept of FSR gives more freedom for design of multi-functional riser system in view of sustainability of DSM. In DSM, sustainability concept may be focused on eco-friendly treatment of seawater and sediment, and safety of total mining system. For feasibility of FSR, however, installation, maintenance and repair need to be investigated thoroughly in collaboration with industry experts"

Jan 1, 2017

By Kenneth E. Gray

The turbulent flow drag coefficients, or friction factors, have been experimentally determined for the cut-tings normally encountered in drilling operations. The gas law and average drag coefficients for characteristically flat particles (limestones and Shales) and for angular to sub-rounded particles (sandstones) were used to extend Newton's equation to a more useful form. The resulting equations are expressions for the slip velocity of a particle as a function of the particle size and shape, the bottom-hole injection Pressure, and the Bottom-hole temperature. The velocities necessary to lift actual rock cuttings as observed in the laboratory were compared with velocities predicted from the derived equations. Results indicate that there is no single correct circulating velocity and that the commonly used 3,000 ft/min linear velocity may he sufficient to lift only very mall particles. The advantage, in terms of horsepower requirements, of cycling high pressure air to obtain lower compression ratios was shown. INTRODUCTION A promising departure from standard rotary hydraulic drilling is air or gas drilling. In many instances the rate of penetration and bit life increases resulting from this method have been very substantial. Further the application of air drilling in areas of lost circulation or water sensitive pay zones has been highly successful. Purpose For the drilling contractor, the practical question remains, "How much air pressure and volume should I have?' lt is necessary to have a reasonable knowledge of the air velocities and pressures required in air drilling operations for the proper design and most advantageous use of surface equipment and for adequate removal of cuttings from the borehole. Eased on experience, most operators agree that at least 3,000 ft/min linear velocity is necessary for satisfactory hole cleaning.' It was the purpose of this investigation to evaluate the drag coefficients, or friction factors, for the cuttings normally encountered in drilling operations, i.e., sandstones, limestones and shales, and to utilize the values obtained to develop an expression for the minimum velocities and pressures (hence the volumes) necessary to lift these cuttings. THEORY Several investigators have done extensive work on the ability of drilling mud to lift bit cuttings. They conclude that the ability of a drilling mud to lift cuttings is dependent on the density difference between the rock being drilled and the drilling mud, the cutting size and shape, the mud flow constants, and the flow state (laminar, transitional or turbulent) of the mud. However, drilling muds are not true fluids but have a variation of viscosity with velocity in laminar flow and a constant apparent viscosity in turbulent flow. A survey of the literature revealed that no experimental work had been done to determine the velocities necessary to lift actual rock cuttings using a compressible fluid such as air or gas. In 1953, Nicolson6 stated that in air drilling fluid mechanics the particles could be assumed spherical in shape and that ; constant drag coefficient of 0.5 could be used due to the highly turbulent flow of the circulating air. By equating the turbulent resistance on the particle to the gravitational force on the particle, he obtained the expression, ^ = 2.67^y ,.......(1) where V, is slip velocity of spherical particle, ft/sec; D is particle diameter, in.; p, is particle density, 1b/ft8; and p, is fluid density, lb/ft3. However, as stated earlier, most operators seem to agree that adequate hole cleaning can be obtained by circulating a sufficient volume of air to give a linear velocity of 3,000 ft/rnin in the annular space. Basic Equation The velocity with which a solid particle freely falls through a fluid will increase until the accelerating force, gravity, is equal to the resisting forces, buoyancy due to the fluid displaced by the particle and friction due to the relative motion of the particle through the fluid. When the accelerating and resisting forces become equal,

By W. Roy Dunbar

"The Porcupine area is in northern Ontario at the intersection of N. Lat. 48° 30' and 81° W. Long. It is 125 miles due north of the Sudbury nickel range. Practically all the mineral production of this area has come from the townships of Tisdale, Deloro, Whitney, and Ogden, in order of importance. The accompanying map of the Porcupine area and its extensions to the east and west (Fig. 4) has been included to show what I consider to be an essential objective of this paper, a perspective for exploration.The discovery of gold ore in the Porcupine area at such an early date resulted from the extension of the Temiskaming and Northern Ontario railway and exploratory survey lines north into unexplored territory, for the early history of Porcupine is inextricably tied to the exploration along Niven's survey lines and the extension of the railway north from Cobalt to Nellie Lake. The following are the more significant events leading to the discovery of gold in Porcupine.1896-E. M. Burwash, employed by the Ontario Bureau of Mines, examined the country along Niven's base line and noted quartz veins that carried traces of gold. He was attached to Niven's survey party.1899-The late W. A. Parks reported on the geology of the portage route from Mattagami river to Night Hawk lake, for the Ontario Bureau of Mines. He noted the occurrence of gold in quartz veins and reported “I regard the region south of the trail to Porcupine lake as giving promise to the prospector"". He also was attached to Niven's survey party.1901-Charles Camsell, while prospecting for the Algoma Central railway, did some work on a vein occurrence carrying low gold on ground now known to be part of the Hollinger mine (3).1907- Extension of the Temiskaming and Northern Ontario railway to Nellie Lake.1909- Bannerman followed up Indian story about occurrence of coal, and found iron formation. He remained to prospect and found the gold-bearing vein of the Scottish Ontario property."

Jan 1, 1954

By Robert Glass Cleland

THOUGH the rapid revival of the copper market in the early twenties solved the most serious of the company's immediate postwar difficulties, a much more fundamental, long-range problem still remained. Mining is not like farming: the earth does not bring forth a new crop of gold, silver, lead, zinc, oil, or copper at every harvest time. Metal taken from the ground does not spring up again from the old roots like perennial flowers in a garden, or find renewal in freshly sown seed. No ore body, whatever its size or richness, is too big or too rich to escape ultimate exhaustion. When the war closed in 1918, Phelps Dodge had been mining copper from Bisbee, Morenci, and Nacozari over periods varying in length from ten to nearly forty years. During much of that time, the company's production had run from fifty million to as high as two hundred million pounds a year. Even the greatest of mines had to respond in time to such a drain. High grade ore was already at a premium in Bisbee and Morenci. The Burro Mountain properties of New Mexico were a disappointment. Failing the acquisition of

Jan 1, 1952

Real time analysis of ore quality between the mine and mill provides major benefits to copper mining and processing operations. Prompt gamma neutron activation analysis (PGNAA) is a proven technique that has been successfully applied for real time conveyed flow multi-elemental measurement. The advantage of PGNAA is that it measures through the full conveyed cross section continuously and provides representative element measurement without the need to constantly sample coarse (primary crushed) conveyed flows. High specification PGNAA analyzers enable accurate measurement over time increments as short as thirty seconds. Elements such as copper can be measured to a precision of 0.02% copper which is sufficient for high confidence in decisions for bulk flow diversion. Increments of eight tonnes are being diverted through a bulk ore sorting application to remove batches of waste from mill feed as well as divert material to different stockpiles based on ore quality. Longer measurement increments of two to five minutes are suitable for blending control of ores to reduce feed quality variability and to control average ore quality within a target range. Feed blends can be adjusted as frequently as required but typically multiple measurement increments are composited to produce a rolling average ore quality. The paper details two case studies where analyzers have been successfully used to measure conveyed flows for blending and bulk diversion applications. The real time measurements of ore composition are also used for ore reconciliation, in metal accounting and providing process operators with advance warning of ore quality changes that may affect grinding performance and cause process upsets. Real time ore quality measurement has proven beneficial in improving copper processing performance through better utilising plant capacity in a leaching operation, optimising ore feed quality, and reducing unnecessary processing of waste. INTRODUCTION Representative real time elemental analysis of conveyed ore quality using fully penetrative technologies has been available to the minerals industry since the 1990s. The Prompt Gamma Neutron Activation Analysis (PGNAA) technique was developed into a conveyed material analyser and soon adopted by the cement and coal industries which recognised the benefits in real time quality management. These commodities were ideally suited to this measurement technique as operations generally involved conveying bulk material prior to processing. Measured quality was used to divert material to different destinations or used to control blending for improved quality consistency. Uptake in the minerals industry, however, has been slow until the last ten years, and particularly until the mid-2010s.

Jan 1, 2019