Search Documents

By Leslie Thompson, Randy Hiebert, Marietta Canty

A paper is presented in which an innovative biological process is described for the treatment of cyanide-, metals-, and nitrate-contaminated mine process water. The technology is capable of detoxifying cyanide and nitrate and immobilizing metals in wastewater from agitation cyanide leaching as well as heap leaching. A pilot-scale demonstration is described in which a pilot plant was constructed to detoxify cyanide and immobilize several metals from a mine process wastestream at a mine in Nevada. The demonstration was performed jointly under the Mine Waste Technology Program (MWTP), which is funded by the U.S. Environmental Protection Agency (EPA) and is jointly administered by the U.S. Department of Energy's (DOE) Western Environmental Technology Office (WETO) and the Superfund Innovative Technology Evaluation (SITE) Demonstration Program under Interagency Agreement Number DW89938513-01-0. MSE Technology Applications, Inc. (MSE) located in Butte, Montana, was the contractor responsible for conducting the project, and Pintail Systems Inc. of Aurora, Colorado, was the technology provider. The pilot-scale unit was field tested at the Echo Bay McCoy/Cove Mine southwest of Battle Mountain, Nevada. The biotreatment process was con­sidered to be very successful in detoxifying cyanide from the mine process water. The process was also determined to be very effective in removing metals. The pH was consistently neutral­ized and nitrates were successfully removed in the mine process water. As a result of conducting these pilot-scale tests, the biotreatment process was concluded to offer an innovative, cost­effective alternative for the treatment of mining wastewaters.

Jan 1, 1998

By Gregg Sherry, Bob Gordan

INTRODUCTION This paper report presents the general case history for the construction of the North Outfall Replacement Sewer (NORS) project. A 1982 City of Los Angeles Wastewater Facilities Plan recognized that a 19.3 km (12¬mile) section of the North Outfall Sewer (NOS), from Culver City to the Hyperion Treatment Plant, was deteriorating and had insufficient capacity. Built in the 1920s of unreinforced concrete and lined with vitreous clay tiles, the originally unventilated NOS suffered considerable corrosion by H2S gas. This caused roof tile and concrete to fall to the bottom of the pipe, which, over the years, reduced the 11.9 M3/S (420 cubic feet per second (cfs)) design capacity of the NOS to a current level of approximately 8.5 M3/S (300 cfs). This worsening condition, thereby contributing to the polluting of Santa Monica Bay. This situation culminated in the State of California Regional Water Quality Control Board, Los Angeles Region, issuing a Cease and Desist Order on January 27, 1986, which required the City of Los Angeles to eliminate such dry weather overflows through a number of prescribed actions. One of these was to construct the North Outfall Replacement Sewer (NORS) by April 1, 1993. PROJECT DESCRIPTION The NORS Project involved the construction of over eight miles of tunnel and related structures. It consisted of a main tunnel conduit to convey sewage to the Hyperion Treatment Plant and four diversion lines connecting the main tunnel to major existing

Jan 1, 1993

By D. C. Willett

INTRODUCTION The Symposium on the Development of Underground Space, held in Seattle, Washington, from October 1 through 3, 1980, was organized by the "Deep Space" subcommittee of the ASCE's Underground Research Technology Council. The primary objective of the symposium was the exploration of the interfaces between the investigation, design and construction of large underground facilities in "deep space" which, for the purposes of the committee, has been defined as starting at 100m below ground surface. The meeting focussed primarily on tunnels, caverns and shafts in hard rock; the meeting format comprised a number of brief presentations concerned with the technical aspects of investigation, design and construction, followed by an open discussion, and concluded with the assembly of recommendations regarding the interface problem by the symposium participants. The principal considerations brought out during the symposium, and a general review of the conclusions, are briefly presented in the following paragraphs. INVESTIGATION The sessions dealing with "Investigation" were chaired by Dr. H. Pratt. Presentations were made by Dr. D.C. Banks, Dr. W.A. Hustrulid and Dr. Pratt. The extent of the interface of the investigation phase with the other (design and construction) phases of an underground facility will depend in large measure upon the nature of the facility; at one end of the spectrum, the investigation must be in continuous and closely coupled relationship with the design of a radwaste facility. At the other end of the spectrum, for (say) a small mining operation, the interface is largely associated with the initial development, with only minor on-going involvement.

Jan 1, 1981

By Robert J. Wise

The mine plan for an underground longwall mine plan usually requires a longwall panel conveyor that begins operation at its maximum length and gradually shortens over the life of the panel. Current mine plans around the United States require initial panel conveyor lengths of up to 4500 m (15,000 ft) and capacities of up to 3.2 kt/h (3500 stph). Because these conveyors are constantly being moved from panel to panel, their components must be as compact and light as possible, and the design must be flexible enough to be modified as new terrain and conditions are met. In the past, when drive horsepowers or belt tensions were exceeded due to conveyor length, a new flight would be added, including additional belt storage units. In some cases, this led to as many as three flights installed in a single longwall panel. As the longwall retreated through each flight, mining was required to stop during removal of the drives and storage units. This sometimes meant several days of lost production. Intermediate drive technology was developed to eliminate this excessive downtime and still keep conveyor belts, motors, pulleys and other components as small as possible. With intermediate drives placed along the carrying side of the conveyor, belt and motor sizes are kept as small as possible, and only one storage unit is needed. Most importantly, as the longwall retreats through a booster drive station, it can generally be removed in a regular downtime slot and no additional production time is lost.

Jan 1, 1993

By E. Bakhtavar

It is considered that the most economical method for the exploitation of Gol-e-Gohar Area 3 iron ore mine is to combine open-pit and underground methods. In this regard, the most critical problem is the determination of optimal final pit depth. In this paper, a method which was recently introduced on the basis of economical block models of open-pit and underground is used to determine optimal final open-pit depth of Gol-e-Gohar Area 3 mine with due regards to the future underground mining option. Considering a low cost and productive underground method as a feasible alternative for extraction of the lower part of this deposit, room and pillar was selected. It is concluded that after the assessment and comparison of different values for depth, optimal final open-pit depth was determined to be equal to 285 m.

Jan 1, 2010

By F. G. Crack

This paper is based on the philosophy that the management structure and strategy required for mine construction and development projects are different from that required for routine production and maintenance operations in a mine. The purpose of this paper is to present an integrated approach to the management of mine development projects. This paper highlights the four major aspects of the integrated approach. First, a brief review of the various types of contract documents is provided. Second, the management organization of a project is discussed. Third, the project manager's role and the field supervisor's responsibility are briefly outlined. Finally, the use of scientific techniques for planning, scheduling, executing, and controlling projects is presented. Each of these aspects is important; however, each by itself cannot be expected to bring order or unifying impact to the complexities involved in overall project management. When all these aspects are coordinated, the result will be a sore successful project from conception to completion.

Jan 1, 1982

By Cyrus W. Field

Chemical, mineralogical, and petrographic data have been obtained for suites of plutonic rock samples from the Guichon Creek Batholith of British Columbia and the Mineral-Iron Mountain-Sturgill Peak- Cuddy Mountain-Peck Mountain areas of western Idaho. Intrusions at these two geographically separate localities represent composite plutons ranging from early gabbro through quartz diorite to late grano- diorite and more silicic-alkalic phases. They are early Mesozoic (200 m.y.) in age, and contain porphyry-type mineralization in close spatial and temporal association with late-stage intrusions of porphyry, aplite, pegmatite, and (or) breccia. Country rocks are eugeo-synclinal assemblages of metasedimentary and metavolcanic greenstones of Permian, Triassic, and Jurassic age. The petrochemical evolution of these intrusions, and the effects of subsequent hydrothermal alteration and metallization, are illustrated by standard ternary diagrams of the major oxide and mineralogical data. Samples plotted on an AFM diagram suggest a calc-alkaline magma trend. However, their distributions on NKC and Qz-Kf-Pf diagram show well-defined trondhjemitic (Na20-rich) and tonalitic (quartz-rich) variants to this trend, which are similar in part to those reported for mineralized island arc plutons of the northern Caribbean and southwest Pacific, but which contrast markedly to those for continental plutons of the Bingham District, Boulder Batholith, districts of southern Arizona, and elsewhere.

Jan 1, 1975

By A. Vien

A major thrust in Industrial automation over the past few years has been the exploration and incorporation of higher level (supervisory and optimizing) control strategies aimed at more fully exploiting the existing control system infrastructure. There is little doubt that this is worthwhile pursuit, however, one must not lose sight of the maintenance and development requirements of the basic control system. Statistics on loop performance indicate that this too is an area of considerable potential. In this paper the authors look at some of the less elegant, but arguably equally important issues in mineral processing plant control. The focus is on controller structures, loop tuning, sampling, filtering, and some of the other principal components of the regulatory control foundations. In many cases significant improvements In control performance can be achieved by getting back to the basics.

Jan 1, 1998

By Norman F. Schulz

The Davis magnetic tube concentrator is a laboratory machine designed to separate a small sample of pulverized magnetic iron ore into magnetic and non-magnetic fractions. It was developed in 1921 by mechanization of a test previously performed manually. (1)(2)(3)(1) No significant changes have been made in the design of the apparatus since that time. The Davis magnetic tube test continues to serve as a practical basis for judging the amenability of an ore to magnetic separation and for controlling magnetic separation plant operations. The apparatus consists of an inclined cylindrical glass tube supported adjacent to closely spaced pointed poles of a powerful C-magnet. (Figure 1). To conduct a tube test, a sample of a suitably prepared ore is poured into the water-filled tube. With wash water flowing through, the tube is oscillated to gradually reject the weakly magnetic ore particles until the desired degree of separation is attained. Both the magnetic concentrate and the tailings may be recovered for examination.

Jan 1, 1963

By Michael M. Carroll, Zhu-ping Duan, Han-ping Chin

INTRODUCTION The inelastic stress-strain behavior of rocks has urged engineers to seek for the possible application of plasticity to engineering pro¬jects such as tunnels, oil wells, dams, etc. for a long time. Early efforts in this direction have tentatively used the classical theories to solve some axisymmetric problems, in which the rocks were treated as perfectly plastic and nonfrictional materials (Talobre, J. A., 1957). Meanwhile, one of the fundamental assumptions is that the volume strain of elastoplastic material is purely elastic. Drucker and Prager (1952) developed a perfectly plastic and frictional model with a generalized form of Mohr-Coulomb law, which serves as both failure criterion and yield criterion. Although the associated flow rule gives unacceptably large dilatancy, this model is a very important step to deal with the frictional behavior of geological materials. As a further step, Roscoe et al (1963) and Schofield and Wroth (1968) proposed a Cam-clay model, which accounts for the yielding before the material reaches a failure envelope and reflects the plastic volume strain as a strain hardening factor, and the open end of the Drucker-Prager envelope is capped by a family of yield surfaces, the envelope is made conforming with crit¬ical void ratio line. The proposed shapes of the cap have been based on experimental data and on convenience of mathematical descrip¬tions. Drucker, Gibson and Henkel (1957) introduced a spherical cap for soils, while in Cam-clay model the cap is semi-logarithmic yield function derived from the result of triaxial tests. DiMaggio and Sandler (1971) proposed an elliptical model for sand, in which the hardening function depends exponentially on plastic strain. Sandler et al (1976) used a plane cap model to express the behavior of a wide range of geological materials of which the nonlinear hysteretic nature is significant. Mizuno and Chen (1982) illustrated the physical mean¬ing of cap models and their adaption to finite element calculation. In recent years, Carroll et al (1972, 1980) have studied the com¬paction of porous materials under hydrostatic pressure and discussed the mechanism of the nonlinear response thoroughly. Analytical and numerical analysis of the hollow sphere model by Curran and Carroll (1979) predicted an initial yielding surface, dependent on the initial porosity, and showed a strong coupling between hydrostatic and deviatoric effects. All these main features from the abovementioned theoretical research are visualized by the experimental data on Boise sandstone (1984). The combination of such previous work would be logically the construction of a plasticity model for porous rocks which, following the tradition of assigning the name of birthplace to a special model, is called Cal-Rock model (Carrol, M. M., 1984). The results of triaxial tests along different loading paths reveal the compaction characteristics for deviatoric and hydrostatic stress separately. the fitting of the nonlinear stress-strain curves leads to a construction of yield surfaces. Moreover, an uniaxial strain test gives the strength envelope which is the critical state line. The whole model is composed in the frame of elasticity theory. The concept and representation of plasticity used here are in the spirit of Naghdi¬Casey theory (Casey and Naghdi, 1984 and 1984, Naghdi and Trapp, 1975). In order to find the way of using such a plasticity model in engineering problems, the stress field in a thick-walled cylinder of porous material is calculated. This is an axisymmetrical problem with plane strain, which is an idealization of oil well in an infinite medium. Because the constitutive relation is highly nonlinear, a numerical method has been utilized to obtain the solution. CONSTRUCTION OF CAL-ROCK MODEL (1). Elastic-plastic constitutive equations The basic assumption is that the yield surface in stress space depends on one parameter, namely the plastic volume strain, as the data on Boise sandstone suggested. Starting from this point, the theory formulated in stress space and in strain space by Naghdi and his co-workers (1975, 1981) can be simplified. The simplified yield function is

Jan 1, 1986

By P. R. Taylor

This investigation (Bowles, 1990) involves consideration of technology utilized by three separate fields of metallurgy and materials science: 1) The recovery of metals employing the use of solvent extraction, 2) The fabrication of materials using powder metallurgy, and 3) The use of composite materials in fabrication of engineering materials. The research considers each of the processes in order to realize the benefits of each. In light of the fact that materials have an intended use -it does seem plausible to simplify the process required between "mother earth" and final use. For instance, a primary copper producer that already employs a solvent extraction and electrowinning process could produce value added products directly. Part of the existing extractant flow could be diverted into a pressurized hydrogen stripping process in order to produce specialty composite powders. Innumerable methods have been employed for the recovery of metals; solvent extraction, the one considered in this study, was used due to the possibility of it providing a pure powdered metal. The use of solvent extraction in the recovery of metals has gained wide acceptance and its use proves beneficial in many applications (Ritchey and Ashbrook, 1984). Pressure hydrogen stripping of solvent extractants may provide the benefit of flowsheet simplification compared to conventional solvent extraction followed by electrowinning. It may also provide the benefit of direct production of high purity metal powder (Demopoulos and Distin, 1985).

Jan 1, 1992

By S. K. Kawatra, J. A. Halt

"INTRODUCTION Iron ore beneficiation needs advances in areas such as process control, automation, burner and furnace designs, silica-free binders, and even alternative iron making routes. While some – like new binders – are only step-changes, all are tools that can help make the ironmaking industry more sustainable. This paper focuses on binders. Binders are added to iron ore fines before they are agglomerated. Binders are used to control the balling process and increase the mechanical quality (e.g. strength) of green-balls and pellets. Agglomeration usually follows thickening and filtration. Good-grade ores, which don't require upgrading, are wet ground to decrease particle size and increase specific surface area. Low-grade ores are often extensively upgraded through wet operations (flotation, dispersion and selective flocculation, magnetic separation, etc.). For both types of ores, thickening and filtration conclude the circuits so that moisture contents are lowered and the ores can be agglomerated. It's been known for a long time that thickening and filtration behaviors are influenced by zeta potential (Sandvik, 1979). Highly-negative zeta potential is good for dispersion while low zeta potential is good for filtration. So, the zeta potentials of iron ore particles are lowered with additions of acid or carbon dioxide, for example, to increase filtration rates and throughputs (Eisele et al., 2005). What happens to particles as their zeta potentials are lowered? Particles aggregate together, effectively forming larger particles. How stable then, are those aggregates during mixing and balling? Are they easily broken up during mixing (if mixers are even used)? Are they broken up during balling? Or, do the aggregates resist breakage so that the availability of ultra-fines, which are so beneficial for agglomeration (Stone, 1968), is decreased? For plants where high doses of bentonite are used as binder, the above questions may be of no concern. The bentonite adds the necessary amount of fines; however, even at those plants, the calcium and magnesium contents in the water affect bentonite's effectiveness (more magnesium and calcium means less effective bentonite). (Engesser, 2003) For plants where new silica-free organic binders are being developed and used, the above questions may need to be considered. The binder is only amongst the iron ore particles for a short period of time – until it burns away or thermally decomposes in the induration furnace – so the liberation, availability and distribution of fine particulates is very critical for the quality of balls and pellets. It was hypothesized that high zeta potential conditions would lead to good pellets, while low zeta potential conditions would lead to relatively bad pellets."

Jan 1, 2018

By R. O. Burt

The paper examines the role of gravity concentration in both an historical contest and within the modern mineral processing industry. It discusses the principles of the process on both a theoretical and practical level. The importance of ore mineralogy and its effect on the choice of the wide range of equipment available is discussed. The paper concludes with a discussion on the relative merits of gravity concentration to other forms of processing and seeks to answer the classical question - "Quo Vadis?"

Jan 1, 1982

By Daniel A. Jones

The Surface Mining Control and Reclamation Act of 1977 establishes a nation-wide program requiring the Secretary of the Interior, through the Office of Surface Mining Reclamation and Enforcement, and the States to protect against the adverse effects of coal mining and to reclaim previously mined lands left without adequate reclamation. The Act requires coal mine operators to: restore the land to approximate original contour, return the land to a condition capable of supporting prior potential uses, protect the hydrologic balance, segregate and restore topsoil, control blasting to prevent damage and injury, establish vegetative cover, and control surface effects of underground mining. The Act also establishes: a reclamation fee on coal, a program to assist small operators, a program to give technical and financial assistance to State programs, State Mining and Mineral Research Institutes., a program for designating areas as unsuitable for mining, and a study on surface mining of minerals other than coal.

Jan 1, 1977

By S. Phillipson

The Mine Safety and Health Administration’s Roof Control Division (RCD) evaluated the use of Shuttle Radar Topography Mission (SRTM) data to identify fracture traces on Earth’s surface. Results were compared to the analysis method employed by RCD for 30 years, which relies on LANDSAT-TM Band 4. SRTM elevation models are expected to provide a direct representation of bedrock surface, while LANDSAT-TM Band 4 represents reflected near-infrared radiation as an indication of moisture content and is only a proxy for possible structures. Three areas in southwestern Pennsylvania were chosen for ground-truthing lineaments derived from both methods, following a series of desktop comparisons in six areas of the contiguous U.S. Field studies that identified numerous instances in which SRTM lineaments corresponded with joints at the projected location, and were oriented within 10° of joint strike, indicating that those SRTM lineaments represented the structural grain of the area. In some cases, lineaments were associated with individual joint zones. Photo-lineaments derived from the existing LANDSAT-TM methodology appear to offer a higher coincidence with expected trends of joints on a regional scale when performing the desktop comparisons, while field observations indicated that SRTM-derived lineaments had a higher association with individual geologic structures in the case study field area. It appears that both methods can identify the structural grain of an area, and that both tend to identify linear segments of valleys where erosion has preferentially occurred along joint zones or other structures.

Jul 1, 2023

By Roshan B. Bhappu

Although the economic importance of recovering copper by leaching of mine work dumps from open-pit operations has been realized for some time, serious attempts to understand and to improve such operations through scientific research has been made only in recent years. This progress report covers the results of chemical, physical, and biological studies pertaining to the dump leaching process and discusses salient features and parameters that may be helpful in improving such operations.

Jan 1, 1968

By S. Tuylu, D. Adiguzel, A. Bascetin, E. G. Savas, O. Ozdemir

"Paste Technology has some advantages comparing to other surface disposal methods. With this method, it is possible to pump high concentrated solid materials to very long distances without segregation problem. However, it is known from Literature that pumpability of materials is completely related to rheological properties of the materials. For this reason, in this study, the rheological parameters (e.g. yield stress and viscosity values) of the paste material prepared from Pb-Zn tailings at various solid ratios (60-85%) were obtained in order to determine the pumpability of the paste material. Additionally, slump tests, which are usually used in mining industry, was carried out. Finally, regression analysis was made between the slump values and rheological parameters of the paste material to find a correlation between two independent parameters. The results showed that there is a great correlation between the slump values and the yield stress of the material. On the other hand, there was no correlation with viscosity: ty=430.28-16.877Sv (R2= 0,94; ty: Yield Stress (Pa), Sv: Slump Value (cm)). Based on the results obtained from this study, it can be clearly concluded that the slump values obtained from a simple test can be used to predict yield stress values of paste materials. INTRODUCTION Recently, surface disposal of mining tailings has become one of the biggest problems in mining industry in terms of environmental issues. Therefore, several researches have been focused on this subject in order to find a best solution or method for this problem. These studies showed that paste technology has some advantages compared to other conventional methods. Tailings thickened to the extent show no segregation of particles during transportation, and relatively small amount of settling occur post-deposition which are often called “paste” (Cincilla et al. 1997). Paste tailing technology has two applications in the industrial area as underground paste fill and surface paste disposal. Paste tailing technology was first started to be used in Grund mine, Germany in the late 1970s (Grice, 1998). Process tailing material, water and - if needed - cement materials, which are the components of the paste, must be blended to obtain a homogenous mixture suitable for pumpability. Consistency behavior of the paste material is determined using a conventional sedimentation cone concrete test (slump). Meanwhile, the slump value of the paste must be between 200 and 250 mm for surface applications (Newman et al., 2001). Additionally, in the case of underground paste system, the optimum slump value must be between 150 and 200 mm. On the other hand, the water content and density of paste at certain slump value change depending on the amount of fine particles in the tailing sample. While moisture of the material will be high, its density will be low because of surface area of particles which increases with decrease in particle size (Meggyes and Debreczeni, 2006). For pumpability of the paste to long distances, slump value of the paste must be good enough to be accepted for use of surface paste disposal. Paste material has a yield stress because they show non-Newtonian behavior and generally is classified as a Bingham plastic fluid. (Cooke, 2008; Theriault, 2003). In addition, the appropriate viscosity value of the paste along with the yield stress must be between 100 and 250 Pa (Bascetin et al., 2013; Bascetin et al., 2014; Bascetin et al., 2015)."

Jan 1, 2016

By H. Shafick Hanna

The major problems are identified the high phosphorus content and the fine dissemination or encapsulation of mineral impurities, in, ,the iron bearing minerals, A process which combined extreme fine grinding techniques with magnetizing roasting or flotation separation methods, is suggested. By these methods concentrates assaying 60-61 percent Fe exceeding the widely accepted upper limit of 56 percent Fe set for these ores, were produced with 75-90 percent iron recovery. Moreover it was shown that the phosphorus content of these concentrates could be reduced from 0.25 to 0.03 percent phosphorus by acid leaching. A brief discussion on production costs based on current and future developments in iron ore processing is given.

Jan 1, 1980

By J. Y. Hwang

Sands are utilized to make molds for metal castings in the foundry industry. Approximately a half ton of sand is disposed of for each ton of metal cast in this country. In Michigan, annual sand disposal amounts to about one million tons. A process has been developed in this study to reclaim sands from a steel foundry. Physical separations are utilized in conjunction with other operations (such as the removal of binder, metal, spruce, washes, etc.) to yield silica and chromite sands with desirable molding properties. Several different separation methods, including electrostatic, magnetic, and various gravitational approaches have been examined. Experimental results are presented. The applicabilities of these separation methods are discussed.

Jan 1, 1992

By Wesley W. Eckles

Microcomputer technology has begun to revolutionize petroleum engineering. Petroleum engineers' use of relatively inexpensive personal computers (PC's) is likely to continue expanding rapidly. Since 1982 SPE's Microcomputer Applications Committee has developed a Society-wide users group, a bi-monthly newsletter (MICROCOMP NEWS), an SPE Short Course, a hardware and software distribution program, and a world wide electronic network (SPE NET). The purpose of this paper is to share SPE's experience in creating a dynamic program for meeting the individual member's need in the application of microcomputers to petroleum engineering. My hope is that this will encourage other engineering and scientific organizations to provide similar programs for their members.

Jan 1, 1985