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By Victor F. Hollister

Introduction Trends of successful discovery technology and psychology emerge from a thoughtful study of various companies' exploration programs. These subjective patterns can be generalized into groups of factors for discussion. Here, for convenience, factors that influence exploration success are separated into management and geologic concerns. Most successful discoveries have a demonstrably favorable management combined with a technically competent geologic input. Both are required. But the management input is decisive. Management factors include the correct definition of management's role; cost of exploration; time needed for exploration; commodity selection; and the fostering of autonomy, creativity, and confidence in the geology department. Geologic factors include imaginative technical competence (field as well as academic), correct development and use of empirical exploration or prospecting models, and dedication. Success comes to those entities that are properly managed and have technological competence. A management team that directs a company's business has been compared to a dynasty. The dynasty lays out policy and follows up with appropriate action. In that management's power is pervasive, the term is appropriate. Management's role is, however, more important. Many examples can be cited where the geologic input was impeccable. But management somehow snatched defeat from the jaws of victory, and the exploration success was turned to a third party's profit. Management Factors Management's role can be broadly generalized to four parts. These are to identify the commodities it seeks, define its part in the exploration process, develop a functioning exploration department, and have the desire to succeed. It must have confidence in its geologists and delegate to them the authority and responsibility they need to operate successfully. Head office management cannot do the thinking for a field staff thousands of kilometers away. There is no substitute for confidence and delegation of authority. Successes came to those who had the freedom to act. Motivation is a management requisite. Management's role is to prevent destructive, internecine political battles within the corporate structure. Most large US mining corporations have well known histories of political strife that have damaged their exploration efforts. Management's role must, above all, include the desire to succeed. There are cases where management has been confronted with a commercial exploration success, but their reaction is to request additional study or exploration. Perhaps the problem of bringing a commercial find into production is beyond their capabilities. But a bona fide discovery sent back for additional work commonly is lost due to that management. The cost of exploration is a factor that management must accept. A variety of studies made during the past 40 years shows the cost per discovery to be $25 million, $38 million, $200 million, or even $290 million. These figures are derived by dividing the total exploration expenditure by the number of discoveries. However, successful management dynasties have a much lower cost per discovery during their management regime. Asarco, from 1948 through 1963, had one of the lowest cost discovery rates in the world. Duval Corp., from 1948 through 1968, had comparably low discovery costs. Placer Development, from 1955, was equally successful. Western Mining in Australia has had one of the longest lived dynasties associated with exploration success. Time is vital in exploration success. Most successful exploration case histories stress sufficient time in project exploration so that the target is well tested. A large target cannot always be adequately evaluated by a few holes (strat or concept testing). Serendipity helps in exploring large targets, but it best operates in a lengthy program. Numerous case histories include pleasant surprises. But these came mostly after the 10th hole. Commodity markets are important factors governing exploration success. Management's decision to explore for a specific commodity can doom its effort if that product suffers from severe oversupply. Unquestionably, progressive copper price increases from 1948 through 1968 helped convert marginal porphyry copper discoveries

Jan 8, 1985

By Robert W. Leonardson

The Questa Molybdenite Mine provides a unique opportunity to study the geochemical dispersion of various hydrothermal events, utilizing drill hole analyses. Numerous post-ore factors have altered the primary ore-related geochemical dispersions to the present day configuration, e. g. dikes, faults, hydrothermal convection cells, and weathering. Due to the interaction of an andesitic volcanic pile with the silicic-alkalic generated volatiles, the geochemical haloes of the Goat Hill deposit demonstrate a marked divergence from the classic Climax-type molybdenite ore body. Certainly, however, the similarities to the Climax-type ore body are apparent as potassically-rich fluids have invaded the highly reactive country rock.

Jan 1, 1984

By Earle J. Klohn

Tailings disposal has rapidly become an area of increasing importance to both existing and planned mining operations. In recognition of the significance of this topic, MINING ENGINEERING is presenting a series of articles on tailings disposal. The first, published in June, outlined some site criteria that influence tailings disposal and some of the design options available to meet these criteria. The following article explores in more detail important design criteria for tailings dams and provides several case study illustrations.

Jan 7, 1981

By R. G. Reddy

Chemical and structural changes occurring during the roasting of refractory gold ores were investigated. Effect of temperature on oxidation behavior of ores was analyzed using TGA, DTA and X-ray diffraction methods. The experimental results showed that the carbon in the ore has to be oxidized to a minimum value before any appreciable oxidation of sulfur occurs. Oxidation rates as a function of temperature were calculated. Optimum conditions under which a successful roasting of the refractory gold ores can be obtained are discussed.

Jan 1, 1990

By G. P. J. Schmitz, F. S. Gouws

In flotation processes the structure of the froth phase contains a wealth of information regarding the behaviour of the plant. Various structural features of the froth phase provide an indication of the froth viscosity, froth stability, mineral content, bubble size, etc., which can all in turn be related to the performance of the plant. In this paper the application of machine learning techniques to exploit information from digital images of the froth phase of industrial flotation plants is discussed. This includes both connectionist techniques to identify control decisions necessary to maintain optimal operation of the plant, as well as symbolic methods, such as induction techniques. Both approaches are used to classify froth structures based on statistical features derived from digitized images of the froth surfaces. It was found that backpropagation algorithms perform significantly better than either non-incremental or incremental induction. Backpropagation algorithms requires significant user input in order to optimally train the neural network as opposed to induction, which requires little user input. In contrast to back propagation, decision tree induction produces easily understandable decision trees which can be incorporated into a rule base or an expert system. Finally, incremental induction provides a simple means to smoothly and continuously adapt induced rules to follow changing process conditions.

Jan 1, 1996

By Tony Szwilski

A correlation between the rank, ash content and coal seam discontinuities and coal strength/stiffness is discussed. Rebound hammers were used to evaluate the strength properties of two coal seams. The coefficient of variability of the rebound tests are compared with those of laboratory compressive strength tests by other investigators.

Jan 1, 1985

By P. G. Semple

For the last four years, the Kilborn Group of Companies has been involved in several major projects in the Confederation of Independent States (CIS). These include the Kumtor project, the Kubaka gold project, the Kazgold project, the Aginskoe project and the Jerooy project. These projects are all in various stages of detailed engineering and construction. Western mining companies are pursuing mining opportunities throughout the world in search of ore bodies for development. The quest for profitable mining ventures has led mining companies to South America and Asia and, more recently, to the former Soviet Union. When considering the CIS, several factors should be considered. The most notable are geography, mining culture and previous mining production.

Jan 1, 1996

It is well established that the results of emulsion flotation in which water-insoluble oily collectors are utilized depend critically on the emulsification of the collector and on its conditioning with the pulp prior to flotation. The flotation tests carried out with magnesite and fluorite using sodium oleate as collector confirmed acidic and alkaline ranges of good flotation. While the flotation results in the acidic solutions depend strongly on the conditioning time and can be very much improved when longer conditioning times are utilized, the tests in the alkaline environment do not exhibit any significant dependence on conditioning. The results obtained with sodium salts of myristic and lauric acids confirm these findings. The observed effects provide additional evidence for the role of the colloidal species which appear in the acidic solutions of weak electrolyte type surfactants, such as fatty acids. The flotation properties of sodium oleate in the pH region in which it appears in the form of oleic acid droplets are mainly determined by the properties of such droplets. The flotation in this pH region closely resembles an emulsion flotation.

Jan 1, 1993

By Wern-ping Chen, Joseph Pratt, Thomas G. Brueckner, Tracy K. Lundin

To address and mitigate discharges from combined sewer overflows in the Providence, Rhode Island area, the Narragansett Bay Commission completed a comprehensive Combined Sewer Overflow (CSO) Facilities Plan in 1993 which included a series of deep rock tunnels. Since completion of preliminary design of the program in 1994, the program has been reconfigured in response to the Environmental Protection Agency’s (EPA’s) new CSO policy. The currently proposed system consists of a deep rock tunnel with two tunnel stubs which will provide230,000 cu m (62 million gallons) of storage at depths of up to 90 m (300 ft). This paper discusses the revised 5 km (3 mile) long deep tunnel system.

Jan 1, 1999

By Douglas R. Malicoat, Christopher J. Pritchard

Tg Soda Ash operates an underground trona mine located In southwestern Wyoming, which utilizes continuous mining machinery to produce 2.OM tpy (2.2M stpy) by shortwall and room and pillar methods. As the mine developed, the Increasing distance from the shafts caused travel times to be a significant factor in planning for mine emergencies. It was decided to construct a barricade chamber, a modified refuge chamber, to Increase safety and to provide an additional escape option in the case of a mine emergency. Fortunately, there has been no need to use these facilities during the last 9 years, but mine emergency planning has been greatly improved.

Jan 1, 1993

By Jean E. Kiel, Rob Dorey, Dirk J. A. van Zyl

1.1 INTRODUCTION This chapter seeks to provide an overview of important factors involved in the implementation of heap leach technology as a vehicle for gold extraction from its ores. Toward this end, brief discussions of the various elements important to this process are presented here. Topics covered in this chapter include a brief history of the process; basic chemical reactions responsible for the process ; characteristics of ores amenable to heap leaching; location of the greatest concentration of heap leach projects in the U.S.; heap leach components, methods, regulatory/permitting considerations; and economic considerations. Most of these subjects are treated at much greater length in subsequent chapters. Thus, this chapter serves as a summary for those which follow, in addition to providing the reader with a feeling for those topics which may be of most immediate interest. 1.1.1 History of the Process Modern Day Precious metal heap leaching technology has developed over the past decade, although the principles of heap leaching per se, as well as those of gold extraction through cyanidation have a long history (see discussion below). However, it is in the past 10 years that heap leaching has developed into an efficient method of treating oxidized gold and silver ores. It has proven to be both an efficient way to extract precious metals from small, shallow deposits, as well as an attractive way to treat large, low- grade, disseminated deposits. Heap leaching has several advantages compared to conventional milling (i .e., crushing, grinding, and agitation leaching). In general, these advantages include simplicity, lower capital and operating costs, shorter start-up times, and less intensive environmental regulatory concerns. A possible disadvantage of currently existing heap leach technology is a potentially lower percentage of metal extraction being obtained from the ore than would be the case with conventional milling (Potter, 1981; Hiskey, 1985; and Thorstad, 1987) The actual principle of heap leaching has a long history as inferred previously. For example, mines in Hungary recycled copper-bearing solutions through waste heaps in the mid-sixteenth century (Hiskey, 1985), and Spanish miners percolated acid solutions through large heaps of oxide copper ore on the banks of the Rio Tinto around 1752. By 1900, leaching operations were employing such techniques as leach/rest cycles to maximize copper recovery (Taylor and Whelan, 1942; Thorstad, 1987). Copper dump leaching is currently

Jan 1, 1988

By J. E. Gebhardt, D. King

Field-testing of a new on-stream X-ray fluorescence analyzer was conducted in a copper concentrator. The evaluation of copper tailings and concentrate streams indicated a statistically acceptable correlation with laboratory chemical analyses. The new equipment employs a “components off-the-shelf” approach to minimize capital cost and maintenance issues and to utilize the latest advancements in X-ray fluorescence detector technology and computer capability. A general description of the system is provided, and performance of the analyzer measuring copper (Cu), iron (Fe), and molybdenum (Mo) is presented.

Jan 1, 2003

By John T. Bartlett

With more stringent environmental and economic constraints being placed on mining operations, it has become necessary to optimize each process to minimize energy and raw material consumption and reduce waste discharge. In most cases, detailed process analysis is required to detect inefficiencies and provide alternative solutions for process improvement. HETSIM, a microcomputer process modeling and simulation system, is routinely used to analyze communition, hydrometallurgical, pyrometallurgical, and coal preparation processes. The process modeling techniques used in METSIM, including process control simulation, will be presented and illustrated using actual plant processes.

Jan 1, 1987

By J. MCGUIRE, E. J. Haas, B. Demich

Near misses can enhance awareness of the potential causes of injury and prompt safety management initiatives. Although most companies require near-miss reporting, the value of these reports and how they influence subsequent actions or controls to reduce on-the-job risks are unclear. Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) conducted a case study with an aggregates company in which near-miss reports were analyzed at each of their locations over an entire quarter during the summer of 2018. Within that quarter, workers recorded 249 near misses. The analysis provides insight into ways that risk-communication and management programs can be improved to reengage workers and their situational awareness on the job.

By Barada K. Mishra

The potential merit of the discrete element method (DEM) as a numerical tool for analyzing process engineering problems involving particulate material is discussed. In this method, the dynamic equilibrium equations for each distinct and deformable body are solved. Therefore, it readily lends itself to modeling large numbers of discrete, interacting bodies as in mineral processing operations where a charge of particulate material is processed. Here some applications of DEM are reported: motion of particles in the ball mill, mixer, and jig. Although DEM has made very little headway in mineral processing research, it is shown here that a host of other areas of industrial interest in the context of flow of particulate materials can also be made amenable to analysis by this method.

Jan 1, 1993

By C. O. Petter

This paper, in its first part, compares the profile and economic weight in the extraction of industrial minerals and aggregates to the so called conventional mining activities (metals, coal, gas and oil extraction) in Brazil. In its second part, a descriptive analysis of the present situation of the education in Brazil is made, emphasizing the graduation and post-graduation formation especially in engineering. The curricular structure of the schools that prepare the mining workforce is discussed and the presence of specific subjects in industrial minerals is evaluated. Finally, considerations are made on the actions being taken in the main universities and companies, aiming to improve the formation of the specialized workforce. The Brazilian mining production, comparing 2010 to 2011 showed an expansion of more than 3% (IBGE, 2012). Not bad, but nothing to do with the 13% growth between 2010 and 2009 (influenced by a recovery effect from the 2008 commodities? nightmare). The commodities that had a rising behavior were titanium, gypsum, nickel, graphite, bauxite, phosphate, chrome and chrysotile. All of them were eclipsed by the impressive growth of iron ore production. Some decreases could be noticed, eg. in zinc, kaolin, magnesite and salt production (DNPM, 2012). In fact, the mining activities followed the positive growth of the country these last 5 years. The commercial balance (exports against imports) was not spectacular (positive in US$ 30 billion in 2010). It is important to notice that the mineral commodities balance was US$ 35 billion, representing 27.4% of the total exports and 15.6% of the total imports of Brazil (DNPM, 2012). In this positive environment, the workforce in Brazil showed progress in number of formal jobs and average revenues.

Feb 23, 2014

By Edward F. Divers, J. Drew Potts

Powered dust-filtering helmets (dust helmets) have become increasingly prevalent in the underground mine environment in recent years. Many longwall operations use dust helmets to reduce the respirable dust exposures of miners required to work downwind of crusher, roof support and shearer operations. While continuous mining sections are usually less dusty, use of diesel equipment represents a new potential health problem. The U.S. Bureau of Mines recently conducted a study to determine the efficiency of a dust helmet on diesel-size particulate. Two underground evaluations were conducted on continuous mining sections that were using diesel haulage vehicles. Model No. AH21 Racal airstream helmets equipped with AS22-3 prefilters, AS23-3 main filters and AS60476 tyvek full-face seals were tested. Helmets were placed on mannequin heads and mounted in the ram car cabs. Andersen Model 298 (eight-stage) personal cascade impactors were used to sample air inside and outside of the helmet. Impactor stages 8 and the final filters were analyzed to determine submicrometer (0 - 0.93 µm) particle concentrations. Results from this study showed that the dust helmet was 94% (± 3% at 95% confidence level) efficient on submicrometer particles. Typically, very little coal dust is observed in the submicrometer size range, therefore, these particles were assumed to be from diesel exhaust. Results from this study indicate that proper use of the dust helmet on continuous mining sections that are using diesel haulage vehicles may be beneficial to the health of miners.

Jan 1, 1991

By H. H. Murray

Recently developed clay deposits that will impact regional and world markets are described. These deposits, their location, geology, and physical properties are delineated. Kaolins from the State of Para in Brazil and from Ukraine; bentonites from Argentina and India; and palygorskite and sepiolite from China are world class deposits that when processed using modem technology will produce excellent products. Other deposits that may affect regional markets are kaolins from China, Australia and Indonesia; bentonites from Georgia (formerly USSR) and China; and palygorskite from India and Ukraine. New ball clay deposits that will affect regional markets are in China and Indonesia.

Jan 1, 1999

By Allan E. Hall

The use of full face boring machines in underground mining has increased considerably in recent years and over 200 raise-boring machines are now in use in the Western World. Several tunnel-boring machines have been tested notably in America, West Germany, Britain and South Africa. A relatively new concept is the blindhole borer, where the machine stands on the lower level and bores a full diameter raise upwards without the use of a pilot hole. Four of these machines have been tested to date in South African quartzites with varying degrees of success. The development of boring technology has created new problems for ventilation engineers and exacerbated several existing ones. This challenge has been met in many varying ways and this paper attempts to provide a review of the current state of the art. Technology and methods are developing at great speed in this field and therefore no final and absolute solutions can be proposed, since each machine and site pose individual problems which are best handled by local knowledge and experience.

Jan 1, 1980

By Bob Snashall

"We could blow that damned fort out of existence if we could run a mine shaft under it!," claimed one Union soldier eyeing Bobby Lee's Petersburg defense line protecting Richmond and Jeff Davis. Puncture the line, take the hill behind, and the Confederate capital would celebrate Yankee jubilee, 1864. That was June. At 4:15 am, July 30, mine boss Henry Reese, sergeant, 48th Regiment, Pennsylvania Volunteers, gingerly entered the mine, dark and muddy. Something had gone wrong. The mine, set to go off at 3:30, hadn't exploded. It had to be checked. The main mine gallery, 1.5 m high x 1.4 m wide (5 x 4 ft) narrowing at the top to 0.6 m (2 ft), forced Reese into a tuck run. Some¬where up there in that 155 m (511 ft) stretch running 6 m (20 ft) under the rebel works, moisture may have doused the charge. Or maybe a fuse splice went awry. Or maybe there was live fire steaming like a locomo¬tive towards 3.6 t (4 st) of black powder. Perhaps now Reese wished this sprint was shorter. For the mine boasted a record break¬ing distance in military annals. Lieut. Col. Henry Pleasants Credit goes to Lieut. Col. Henry Pleas¬ants, commander of the 48th, who overheard the soldier's claim for what a mine could do. In peacetime, Pleasants had been a railroad engineer working on the Sand Patch Tunnel. He later switched to mining, working for the Philadelphia & Reading Coal & Iron Co. He even married the daughter of the editor of The Miners Journal. Grieving over his wife's early death, Pleasants plunged into the ven¬ture of war. This Union officer took the mine idea to the brass. Headquarters was less than enthu¬siastic. "The chief engineer of the Army and the rest of the regular Army wiseacres said it was not feasible," Pleasants wrote to his uncle. The pros scoffed, ticking off a list of horribles: No mine has ever gone that far, men will suffocate and be crushed, the rebs will countermine, the men will be trapped. Still, Pleasants eked out a signal to proceed. In the meantime, the miners of the 48th had commenced to dig anyway. It was like the 48th to proceed against the odds. The 48th Pennsylvania Volunteers The 48th had been recruited from Penn¬sylvania's Schuylkill County, anthracite coal mining country. The mines had been torn with strife over wages. Strikes and rioting were prevalent. Murder was not unknown. This "Buckshot" resistance centered in Pottsville, PA. It forced the governor to call in troops. Coal was in high demand to run the war machine. Pennsylvania operators worried that a military draft would stir up violence, closing the mines altogether and further shift¬ing business to emerging Illinois mines. Men lit out for the western gold fields in the tens of thousands. Secret societies bred in the mining camps invited draft agents to dance at the end of a rope. Jobs threatened by cheap, victorious South¬ern labor were one warning intended to get immigrant miners interested in the war. Operators gave miners time off to help de¬fend Philadelphia during Lee's thrust to Gettysburg. Even so, the draft spawned new violence and troop intercession. Soldiers were not welcome. The dust had barely settled when into this Pennsylvania "minefield" marched the 48th on a recruitment drive. The 48th had been in Lexington, KY on guard duty. When it came time for the regiment to pull out, the townspeople had prevailed upon authorities to extend the regiment's stay. Finally ordered to move out, the 48th was feted by a hanky-waving, tear-dropping send-off to the lyrical lament Auld Lang Syne. And Kentucky fancied itself to be rebel. Striding smartly into the Pennsylvania coalfields, the 48th attracted 400 recruits and marched off under regimental colors specially made by the proud citizens of none other than Pottsville, PA.

Jan 1, 1989