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By Robert J. Garino

Around two-thirds of world silver mine production comes from mines where the majority of ex-mill revenue is obtained from other metals. In this talk I will illustrate the importance of this output of silver as a by-product of the mining of various base metals. I will also consider the impact of relative changes in base and precious metal prices on mill-head revenue, and therefore, on production decisions. During the latter half of 1982 improving silver prices encouraged re-openings at several base metal mines. Thus some production of lead, zinc and copper can be regarded as partly conditional on the prevailing silver price. Conversely, a good deal of silver production can be considered to be independent of the silver price and dependent on the production of some base metal. It is the degree to which the value of silver mined affects the revenues of nominally, base metal, producers that is the central concern of this presentation.

Jan 1, 1983

By G. Castillo, J. Mortensen

"INTRODUCTION Molybdenite is typically produced as a co-product in the copper ore flotation process. At the Rio Tinto Kennecott Concentrator (RTKC) in Copperton, Utah, the molybdenite is initially floated with copper sulfides and other value minerals producing a Cu-Mo concentrate. This is then separated in the molybdenum plant by depressing copper sulfides and pyrite and floating only molybdenite. The molybdenum plant in RTKC comprises the rougher circuit and several stages of cleaning to achieve a certain grade requirement of Mo. The rougher circuit is where the first stage of separation occurs. Cu sulfides and pyrite are depressed in the rougher circuit by adding NaSH under nitrogen and in the cleaner circuit by adding NaSH under air. The depression of Cu sulfides (and pyrite) by NaSH is related to the redox activity1. It is important therefore to maintain a reducing potential in the circuit in order to achieve effective Cu-Mo separation. If the rougher circuit is under air, like RTKC’s molybdenum cleaner circuits, it is harder to maintain the target redox potential because NaSH oxidizes rapidly in the presence of air thereby increasing NaSH consumption significantly. CU-MO SEPARATION AND ROLE OF PULP POTENTIAL The collector adsorption on copper sulfide minerals is through an electrochemical mechanism2. The collector changes the surface chemistry of the Cu mineral allowing it to float. Molybdenite, or MoS2, on the other hand, floats readily in the presence of a frother as it is naturally hydrophobic. Usually, hydrocarbon oil extenders such as diesel or burner oil are added to enhance Mo recovery. In order to effectively separate Cu from Mo, the collector complex on the copper surface needs to be destabilized or desorbed using a reducing agent such as NaSH or Nokes. As long as the circuit is under highly reducing conditions, the collector remains detached from the sulfide mineral surface allowing Cu sulfide depression. Therefore, it is important to measure the oxidation-reduction potential (ORP) continually and maintain the reducing condition with addition of NaSH. For a given collector each mineral will have a characteristic potential or electrochemical window for flotation to occur3, therefore, it is necessary to reduce the potential outside of this window in order to effectively separate Cu and Fe sulfides from MoS2 minerals2. In RTKC plant, the target reducing condition is between -450 to -550 mV to effectively destabilize the collector and depress Cu and Fe minerals. Typically the dosage of NaSH used in the molybdenum plant could range from 6 to 30 gallons/min (gpm). The high dosage of NaSH could pose risk of H2S exposure. RTKC wanted to evaluate alternatives to NaSH in order to reduce its consumption and minimize risk of H2S gas generation."

Jan 1, 2016

By C. Newman, N. Schaefer

"INTRODUCTION As underground mining continues to operate at deeper depths and in more complex geologic and geometric conditions, there has been an increased demand for higher design standards in ground control safety and stability within the mining industry. Over the past 20 years, NIOSH has developed, validated, and distributed a number of free software packages (ALPS, ARMPS, AMSS, ARBS, etc.) for the safe design of underground coal mines with respect to ground control. While these programs were initially developed on a, “stand alone model,” where all program data resides on an individual or workgroup computer, modern day web applications have begun to migrate toward a, “multiple-tier model,” allowing multiple users to access an application through an Internet connection. webGroundControl provides users with access to NIOSH ground control design software (ARBS, ALPS, and ARMPS) utilizing a web-based three-tier architecture allowing users to easily access ground control designs, perform on-demand calculations, and provide online collaboration between operational personnel and engineers through a web server. Given advancements in cloud computing as well as the expansion of Internet connectivity on the surface and underground, webGroundControl users will be able to access the applications anywhere (where permissible) at any time. As web-based computing technologies continue to advance and cloud computing gains popularity and momentum, there is an industry need to develop Internet based applications for mine and ground control design (Barczak et al., 2016). The purpose of this paper is to introduce and familiarize those in the mining industry with the basic framework and, more specifically, the user-interface of the webGroundControl application. It is expected that the mining industry will rapidly embrace this new product and webGroundControl will be a new paradigm for mining engineering computer applications. APPLICATION ARCHITECTURE With the advent of cloud computing, web-based applications have become more popular with their adoption of multiple-tier, or n-tier, architecture containing independently operating tiers. The three-tier application architecture utilized in webGroundControl (as outlined in Agioutantis and Newman, 2016) contains a Presentation Tier (Web Server), Logic Tier (Logic/Application Server), and Data Tier (Data Server) as shown in Figure 1. While tiers have the ability to be deployed across and operating on multiple servers, webGroundControl is currently being deployed on a single server located on a university desktop computer. The separation of the application into a series of tiers greatly increases the maintainability and scalability allowing for the adoption of new technologies that can be applied to a single tier without redesigning the software package. The Presentation Tier maintains the user interface translating client requests (through a web server) and displaying results (through a web browser). The Presentation Tier allows for on-demand access from multiple users and compatibility with a variety of personal computers, Smartphones, tablets, etc. on different operating systems. The Presentation Tier has been developed with respect to the HTML and JavaScript languages. Through the utilization of CSS, a coding language which describes the style of an HTML document, the webGroundControl display is able to spontaneously adapt to any browser and any screen. The development of the Presentation Tier will be discussed in more detail in subsequent sections of this paper."

Jan 1, 2017

By C. Ek

Tailings originating from the gravity concentration of a gold ore containing about 14 g/t Au have been treated by various beneficiation methods. These tailings have been screened on the 147 and 74 micron sieves and the two coarsest fractions have been separated on shaking tables with unsatisfactory results, but the concentrates have been examined in polished sections for mineragraphic analysis. Very simple flotation flowsheets have been applied to collect most of the gold, recovery and grade varying with the regrinding time in a ball mill. Cyanidation tests have shown that this type of treatment is also applicable to such tailings.

Jan 1, 1991

By R. S. Kasper

This paper reviews the procedure used to quantify the conveyor frictional resistance on a 3.9 km (2.4 mile) long overland conveyor belt. Field torque measurements of the three drives were used to help fine tune a computer simulation of the conveyor. This enabled the prediction of the effect on various conveyor components that cold temperatures will have on increasing the throughput tonnage.

Jan 1, 1995

By R. E. Vivas, J. A. Villa

"INTRODUCTION Located in the state of Colima, Peña Colorada is one of the largest iron ore operations in Mexico. The project is owned in equal parts by ArcelorMittal and Ternium. Though boasting a production capacity of 4.5 million tons of concentrate per year, Peña Colorada is faced with declining ore grades. In order to respond to this situation, Peña Colorada had to expand production even further. This expansion created various challenges that were overcome by the adoption and application of new technology. Examples of these technological innovations are discussed in detail in this paper and include improvements in geo-modeling, mine planning and mine operations. The successful implementation of these technologies paid for itself many times over, and has led to significant improvements in production and performance, while lowering the operating costs and reducing the variance between planning and execution. PROJECT OVERVIEW Peña Colorada is a mining company which produces about 30% of the iron ore in Mexico. This project generates about 1,200 direct jobs and 3,000 indirect jobs, making a significant contribution to the local economy. Similarly, Peña Colorada invests in its local communities through numerous educational programs, scholarships, university agreements, social development, environmental agreements, etc. Peña Colorada’s operations consist of an open pit mine located in Minatitlán and a pellet plant located in the port city of Manzanillo, as shown in the location map below:TECHNOLOGICAL INNOVATIONS Most mining projects around the world typically follow the logic of “mining the next best ore”. Consequently, head grades tend to decline over the life of the mine. In the case of Peña Colorada, a decline in head grade combined with a decline in iron ore prices forced the operation to adapt to a new business environment and adopt new technologies to face these challenges. However, the first step along this process was to increase the confidence and reliability of the resource model. This task involved additional drillhole campaigns coupled with more detailed modeling techniques. Once the block model was completed, new optimization studies and production schedules were evaluated with new optimization tools that unlocked significant project value in many aspects of the mine plan. Similarly, new geotechnical studies were prepared, which provided new guidelines for pit slope design, and new technology was implemented to monitor ground movement and slope stability. The picture below shows two sectional block model views in MineSight 3D, along with the pit designs and geologic solids"

Jan 1, 2017

By S. F. Diehl

Suites of monomineralic sulfide and carbonate minerals, as well as mine-waste composite samples, were analyzed using chemical and microanalytical techniques to understand behavior and bioavailability of mine waste elements such as Cu, Fe, Pb, or Zn. Petrographic, scanning electron microscopy (SEM), and laser-ablation inductively-coupled mass spectrometry (LA-ICP-MS) studies of mineralogical residence sites of trace elements are important because trace elements affect the chemical and physical behavior of minerals. Leachate solutions show that chalcopyrite, bornite, azurite, malachite, and galena are host to the trace elements Ag, Al, As, Cd, Co, Cr, Mn, Ni, Pb, and Zn. SEM studies reveal whether these trace elements occur within mineral inclusions or are substituted within lattice structures. SEM analysis reveals mineral phases not identified by X-ray diffraction (XRD), such as inclusions of sphalerite and cobaltite(?) within chalcopyrite.

Jan 1, 2010

By Unto Paakkinen

The testing of different kinds of process flow configurations and cell volumes in industrial scale flotation processes is in general difficult to accomplish and even expensive to perform.1 Also the lack of suitable measuring and analyzing devices often prevents effective comparison of results. Nowadays, the existing flotation processes contain, almost with exception, several return loads which result in difficult control of the process. There exist two good reasons for testing different kinds of flotation circuits at the Outokumpu Oy Kotalahti mine. Firstly it is easy to change the process flow configuration without any additional installation work and secondly, the concentrator is highly automated with magnetic flow meters, on-line analyzer and process computers. In this presentation, open circuit flotation is compared with the classical closed circuit flotation which contains return loads. In additional, the effectiveness of computer control in both cases is estimated and also the effect of cell volume on flotation results is examined.

Jan 1, 1977

By J. Zhai, Z. Yin

"The electrokinetic and flotation behaviors of ilmenite using lead ions as the activator and sodium oleate as the collector were studied. The results of microflotation show that the flotability of ilmenite can be improved by lead ions obviously. The isoelectric point of ilmenite increases from 5.32 to 7.7 after the addition of lead ions because of the adsorption of Pb2+ and Pb(OH)+. The results of zeta potential measurements and the collector adsorption density calculation show that the adsorption of sodium oleate on the ilmenite surface via chemisorptions in addition to electrostatic interactions. Besides, the adsorption density calculation results show that as the addition of lead ions as the activator, the adsorption amounts of collector are greater than those without activation which is in aggrement with the flotation behaviors. INTRODUCTION Ilmenite, as an oxide mineral of formula FeTiO3, is usually used as the main resource of the extraction of titanium (Bulatovic and Wyslouzil, 1999). There are many researches showing that the conventional methods, such as gravity separation, magnetic separation and flotation, do not work efficiently as expected (Mehdilo et al., 2015; Zhu et al., 2011). Nowadays, to produce ilmenite concentration feasibly and efficiently, these separation methods above are combined for a reason that the raw ilmenite ores are characteristic of poor, fine and complicated. Moreover, surface modification, such as surface dissolution method, microwave irradiation and oxidation roasting, is applied to improve the flotability of ilmenite currently (Welham and Llewellyn, 1998; Zhang and Ostrovski, 2002). Generally, fatty acid salts are used as the collector for the flotation of oxide minerals and sodium oleate is usually used as the collector for the flotation of imenite ores (Fuerstenau and Pradip, 2005). The mechanism, such as individual ion electrostatic adsorption, chemical adsorption, ion–molecule dimeric complex adsorption, and the coadsorption of ion and molecule, have not been discussed systematically using sodium oleate as the collector in the flotation of ilmenite (Somasundaran, 1983). Under the activation circumstance using the lead ion as the activator and sodium oleate as the collector, the interaction mechanism seems to be still unclear. In the present study, the interaction mechanism between ilmenite and sodium oleate using lead ion as the activator are studied by microflotation, zeta potential measurements and adsorption density calculation. EXPERIMENTAL Materials and reagents Pure ilmenite minerals were obtained from Panzhihua, Sichuan province, China. The minerals were ground in a porcelain mill with an agate ball. Following that, the prosucts were sieved, and the samples of -0.074+0.038 mm size fraction were used for the microflotation experiments. The results of XRF show that the content of titanium element is 30.58%, showing that the purity of ilmenite is above 90%. On the basis of the results of XRF, it is determined that the purity of ilmenite is very high and meets the needs of microflotation"

Jan 1, 2017

By F. G. Rinker

The world demand for metallized iron continues to increase, keeping pace with steelmaking requirements for lower cost hot metal. Virgin iron ore and in-plant oxide fines can be reduced to direct reduced iron (DRI) and hot briquetted iron (RBI). MR&E has developed an improved coal-based process for cost-effective production of either DRI or HBI. Starting with dry compaction, the process combines the latest technology for material preparation, rotary hearth furnace construction and environmental control. Coarse iron ore fines are blended with pulverized non-metallurgical coal to produce a highly metallized (>90%) product. This paper presents production and installation cost data based on operating and under-construction iron oxide reduction facilities.

Jan 1, 1999

By T. Shumka, M. J. Druckenmiller

"INTRODUCTION As we push further into the 21st century and closer to a more efficient mine, safety and operational enhancements are the two major keys towards attaining success. The Crusher Vision Automation System (CVAS) is a technological advance that will allow an operator to achieve higher safety and higher operational goals in the same piece of equipment. The CVAS is a patent pending system and method for measuring and maintaining the closed side setting (CSS) on gyratory crushers. In the same equipment and technology package, the CVAS will also allow safer placement of main shaft pieces for maintenance and replacement. This technology yields multiple uses and allows a site to significantly enhance safety and operational efficiencies. This measurement technique is used to provide more accurate data and faster data collection times than current techniques used today. It will give crusher operators accurate and reliable measurement for the CSS in a live, operating environment. Measurement data can be collected in five minutes allowing for fast adjustment of the mantle position and subsequent enhancement and streamlining of a crusher and downstream flowsheet. The advantage of this system is that it is permanently mounted at the crusher location, where the operator can turn the system on and off as many times as they like throughout the day with a goal of maintaining a constant CSS gap based on production and maintenance criteria to help streamline operations and enhance safety efficiencies.Regarding its other main functional area, mainshaft maintenance, it allows this work to be performed remotely while keeping personnel safer and out of harm’s way. SAFETY ENHANCEMENT The safety factor enhancement with this system is extreme. It does not require the use of overhead cranes, cleaning out the crusher, lowering people into the crusher or having the operator lower paint cans or lead balls into the crusher pocket while the crusher is in operation for measuring the setting. In order to perform the CSS measurements, the operator only needs to operate the laser through manipulation of a joystick while watching the video feed. Danger of a person falling into the crusher while trying to take measures is eliminated, as are the effects of handling lead balls and tracer dyes."

Jan 1, 2015

By Y. Guan

The adsorption of zinc species onto silica in ammonical solutions has been studied. Adsorption isotherms reveal that increasing adsorption occurs as the solution pH is made more alkaline. Fr-IR spectroscopy revealed that the adsorbed species is a zinc ammine complex.

Jan 1, 1993

By Rameshwar Sah, L. R. Singh, SIVALINGARAJU BARISETTY, SHYAM YADAV, P. K. Ghorui

Fly ash is a by-product generated from combustion of coal in thermal power plant. Disposal of fly ash is a major environmental concern for the power plants. Though a considerable part of fly ash is used in cement making and brick manufacturing, substantial quantity remains unutilized. Silica and alumina are the major constituents in fly ash along with lime. Aluminosilicates and unhydrated lime present in fly ash, in presence of water, undergo a pozzolanic reaction and form cementitious bond which holds the particles together. Bentonite is commonly used as binder in micropelletization of process waste to attain the mechanical strength required for handling and transportation. The bonding of particles by bentonite is a physical mechanism, while fly ash bonding is a chemical mechanism. The present paper deals with the partial replacement of bentonite with fly ash in micropelletization without affecting the quality of micropellets.

Jul 30, 2021

By Thos. B. Douglas

In 1907, the Oklahoma Portland. Cement Company built a small dry process plant at Ada, Oklahoma, then Indian Territory. This plant was later acquired by the Ideal Cement Company of Denver, Colorado, who in 1918 built a new wet process plant along side the old dry plant. The older plant was later shut down .and eventually razed. In 1955, the Ideal Cement Company decided to increase the production at its Ada, Oklahoma operations. After many studies it was decided to build a complete new plant along side the old, near the site of the original 1907 plant. .The new plant was to have a. production of three million barrels annually while the plant then in. operation had an annual production of two and one quarter million barrels

Jan 1, 1961

By R. W. Sims

"He?s an SOB, but he's my SOB." Many of us have heard this line in reference to attorneys, and can appreciate the humor. However, the thought reflects a deeper attitude that lawyers should be used for attack purposes in the legal system or the regulatory process. Often, more permitting progress can be made with tact and flexibility than with inflexible, overly aggressive strategies. Usually, administrative hearings or other litigation work to the disadvantage of the applicant. Thus, I have concerns about approaching any permitting system with a hard-line attitude. On the other hand, the project team must always be prepared to defend permit applications and present a legally adequate case at public meetings, administrative hearings, or judicial proceedings. This paper discusses a number of strategies intended to increase the probabilities for successful permitting, whether opposition is informal or highly organized.

Jan 1, 1990

By Joseph W. Johnson

General Electric introduced electric drive systems on 85 ton Off-Highway mining trucks in the early sixties. Due to favorable economics, trucks have increased in size to handle larger payloads. Series Motorized Wheel systems were developed to meet this demand. When the technology was available, General Electric switched from use of Series motors to separately excited motors with the added benefits of static exciters and simplified control. Over 20 years of electric drive experience have been incorporated in the STATEX drive systems, which covers truck sizes from 85 to 220 tons. This paper traces the drive system developments from the early stages to the present and takes a look at what's ahead.

Jan 1, 1983

By M. T. Ityokumbul

Concentrate flowrates have been measured for the flotation of -100 mesh Lower Kittaning coal in a computer controlled 0.076 m x 3.5 m pilot flotation column. The variables studied were recovery zone height), air flow rate, and solid feed concentration. The size distribution of concentrate and tailings samples were determined. The results obtained show that the concentrate flow rate was independent of collection zone height, but dependent on the gas flow rate, solid loading and particle size. New correlations for column carrying capacity and yield are provided as a function of these fundamental operational parameters.

Jan 1, 1997

The Longwall Strata Control and Maintenance System (LoSCoMS) is designed to monitor shield pressures in real-time from longwall faces and to provide on-line information related to underground strata behavior and longwall mining operation. The information includes shield pressure data with statistical analysis of setting, developing and final pressures, prediction of shield pressures for the following shift or day, etc. and maintenance data on the shields. The LoSCoMS has been installed and tested at Shoal Creek Mine operated by Drummond Company, Inc. The system is providing valuable information to mine operators for better understanding of underground behaviors. As a result, it has become an effective tool for minimizing ground control hazards and reducing out of seam material.

Jan 1, 1997

By L. W. Swent

Dr. Emrick, honored guests, distinguished speakers, ladies and gentlemen, I am Langan Swent, Vice President for Environmental Affairs and Occupational Safety and Health, of Homestake Mining Company. Today, I appear on behalf of the American Mining Congress, as chairman of its uranium mine health subcommittee. The American Mining Congress is a trade association of several hundred members, which include the producers of a large proportion of the nation's uranium. I've been asked to make a statement of principles for the uranium industry. There are two types of principles that apply to industry in general, and specifically to the uranium industry. Some have external origins and apply regardless of what industry does or thinks. Others are generated by industry itself and serve as goals for the industry. I'll discuss some of each type. I'll limit my statement to those principles related to the subject of this conference--radiation hazards in mining. I won't take your time trying to explain some of the unrelated principles that we must all contend with, such as Parkinson's Laws, Murphy's Law, and the Peter Principle. First and foremost, industry has a sincere interest in the well-being and health of its employees. There are two basic reasons for this. One is a basic respect for human lives, especially those of people we see and work with every day. No one in management wants to carry the lifelong burden of blame for a life lost due to poor working conditions. Most uranium and other mining is done in small communities. Production workers, maintenance workers, service workers, shift bosses, foremen, superintendents and managers all live in the same community. They attend the same churches. They serve together in civic activities. Their children go to the same schools. If one employee in such a community loses his life due to poor working conditions, those remaining know in a daily and intimate way the resulting personal tragedy, usually of a bereaved widow and fatherless children. This sad experience makes the community, including industry management, intensely sensitive to the need for maintaining good working conditions in the mines. But what about the segment of industry that does not live in the mining communities? Corporate and owner's offices are frequently hundreds of miles from the communities where the mining takes place. Many of these people are not personally acquainted with the workers, and there are few close personal ties between the two communities. The distant staff are, however, still human beings and motivated by the same basic human respect for life. Mr. Manuel Gomez of MSHA and a member of the planning committee for this conference summed this point up expressively when he told me: "No one group has a corner on compassion." In addition to compassion, there is another factor. In both communities the basic assignment to everyone is to produce profits. In carrying out this assignment, supervisory and management people are acutely aware of the high cost of illnesses and accidents. Their objective of maximizing profits is advanced significantly by minimizing illnesses and accidents at the mines. A business that has illnesses and accidents generally suffers from poor employee morale and high employee turnover, both of which detract from profits. Next, I would like to talk about what industry has done in the field that is the subject of this conference. We have worked at all sorts of methods to reduce exposure of employees since the exposure standards were first introduced and then lowered. Other speakers will go into details of technology, and I'll simply comment on exposure results. These are best shown in Table 1. The table shows the average WL to which miners in U.S. underground uranium mines have been exposed since 1937 through 1980. The trend of decreasing radon daughter concentrations throughout the period is obvious. Figure 1 presents this data graphically and shows the trend at a glance. This record begins in 1937 when uranium, as such, really wasn't being mined or sought. The concentrations given by the U.S. Public Health Service were for a few small vanadium mines which carried uranium as a by-product. A few years later, when the Manhattan project to develop the atomic bomb was begun, these mines became the first U.S. uranium mines and the vanadium became the by-product! The radiation hazard then also received attention and the average concentrations began to decline. As knowledge of the reality of the hazard spread, conditions improved. The search for uranium in the U.S. turned up new and larger ore bodies that had to be mined by large underground mines. These mines involved ventilation planning from the beginning, and when they came into production in the late 1950's they lowered the average concentrations greatly. Then in 1960 the American Standards Association adopted a standard setting 1 working level as a satisfactory condition, and several action levels up to 10WL, at which point removal of people from exposure was called for. As a result of the uranium producing states governors' conference in December 1960, state mine inspection agencies, in the early 1960's, began to adopt and enforce the ASA standards. As a result, average concentrations again declined. In 1967, the Federal Radiation Council recommended an annual limitation of 12 WLM per individual. This represented a great change in the methods of

Jan 1, 1981

Power plants that utilize conventional wet flue-gas desulfurization methods produce enormous amounts of flue-gas scrubber sludge. A typical 400 MW power station that burns a high sulfur coal produces 170,000 tons of wet flue-gas scrubber sludge per year. This scrubber sludge is currently landfilled at an enormous cost to utility companies. This material could be used as a raw material for industries that use gypsum, such as the wallboard and plaster industries. However, before it can be used as feedstock for these industries, some of the impurities such as unreacted limestone and silicates must be removed from the scrubber sludge. Froth flotation has tremendous potential for separating these impurities from scrubber sludge. In order to select an optimum flotation process, it is necessary to characterize the surface properties of the major components in the scrubber sludge, which consist of calcium sulfite, calcium sulfate, calcium carbonate (limestone), and silica. In this study zeta potential measurements were used to determine the surface charge of the components in scrubber sludge, with the goal of optimizing a froth flotation process to produce a marketable gypsum product for the wallboard and plaster industries.

Jan 1, 1996