Search Documents

By M. Fan, M. Mankosa, G. Luttrell

"Column and other non-conventional flotation approaches continue to provide benefits where conventional flotation processes have exhibited limited success. This is particularly evident with respect to flotation of ultrafine and coarse particles. Advancements in air sparging technology have provided the ability to produce finer bubbles than previously possible. The generation of finer bubbles coupled with the froth washing capabilities of a flotation column has demonstrated improvements in ultrafine particle recovery while simultaneously producing a high-grade float product. On the other side of the spectrum, the use of these sparging technologies while applying flotation fundamentals to a fluidized-bed reactor has increased the maximum floatable particle size up to and in excess of 3 mm. Benefits of higher recoveries and reduced reagent consumption have resulted from the use of these technologies. An additional benefit includes a reduction in plant grinding requirements. As such, this paper describes the application of Cavitation-Tube sparger technology and fluidized-bed flotation (HydroFloat). A review of data from industrial and pilot-scale applications is also provided.INTRODUCTIONConventional (mechanical) froth flotation is considered the workhorse of the minerals processing industry. This low-cost process makes it possible to selectively recover minerals by exploiting the difference in surface characteristics (e.g., wettability) of the valuable component and the waste material. Unfortunately, the upper particle size limit for flotation rarely exceeds 0.600 mm, and is typically maintained at less than 0.300 mm for most industrial applications. For many commercial base metal plants, the particle size range for optimum recovery is typically between 0.01 and 0.1 mm (Lynch et al., 1981). This finding is not novel. In fact, the effect of particle size on flotation recovery was studied as early as 1931 by Gaudin et al. who showed that coarse (+0.250 mm) and extremely fine particles (-0.010 mm) are more difficult to recover than particles of an intermediate size. The loss of recovery is due to inherent limitations associated with the flotation process, including bubble-particle adhesion and collision, detachment, buoyancy, and transport."

Jan 1, 2010

By I M. Turnbull

QMAP (the Quarter Million Mapping Programme, 1:250 000 scale) is a geological mapping programme which will build a digital geological database of the whole country and publish maps and books to document it. The programme was established in 1993, following a recommendation by a review panel appointed by the Ministry of Research, Science & Technology, and is funded by the government, from the Public Good Science Fund. The relevance and fundamental value of QMAP lies in the greatly improved geological knowledge it will provide for researchers and other end-users of geological information.   QMAP research involves assessment of previous work, field and laboratory investigations in key areas, and data storage, manipulation and publication using Geographic Information Systems (GIS) computer technology. The QMAP digital database of New Zealand geology will be completed by 2006, as will the series of 21 full colour printed geological maps and accompanying explanatory texts. Two are already completed and published (Kaitaia and Dunedin), and six other projects are well advanced.   QMAP information will also be available in digital form. Next year we hope to expand the scope of the programme to cover the reconciling and linking of many other earth science databases to QMAP, because we believe this will create a powerful research tool. The intention is to develop internet access to the databases, to make the information publicly available.

Jan 1, 1997

By Mike Ounpuu

"Locked cycle testing has become more common practice in the last 10 years. Reasons vary from a desire to avoid pilot plant testing, demand for more variability testing within deposits, and perhaps most importantly, a request from the financial institutions who invariably finance many of the projects. Surprisingly, many people don’t understand locked cycle testing, analysis and balancing. This paper provides a brief overview of locked cycle testing, and then progresses into a more detailed discussion on the analysis and balancing of locked cycle test data. The paper endeavors to educate CMP personnel on how to determine if the test was good and if a reasonable metallurgical projection was made. The paper uses case studies to illustrate the key points.INTRODUCTIONA locked cycle test is a repetitive batch used to simulate a continuous circuit. The basic procedure has a complete batch test performed in the first cycle which is then followed by similar batch tests which have “intermediate” material from the previous cycle added to the appropriate location in the current cycle. These batch tests, or cycles, are continued in this iterative manner for an arbitrary number of cycles. The final products from each cycle, i.e. final concentrate and final tailings, are filtered and thus removed from further processing. At the end of the test, all the products, final and intermediate, are dried, weighed and subjected to chemical analysis. The test is balanced and a metallurgical projection is made.This description can be found in many of our classical textbooks for the mineral engineer 1, 2, 3,4. Unfortunately, none of these textbooks provide any discussion beyond the basic procedure. Often, they provide comments such as in Taggart’ where he states; “It is questionable whether in any case it approximates mill results any more closely than the standard batch test”. It is truly surprising that our classic textbooks promote that locked cycle tests are more art than science, and suggest that they can be of dubious value. None of the textbooks provide meaningful insight or discussion in how to assess:"

Jan 1, 2001

The offshore Maui gas/condensate field was discovered by Shell BP and Todd on Services Limited in 1969. Subsequent appraisal drilling and negotiations with the Government led to a development agreement, æThe Maui White Paper' being concluded in 1973. Part of this agreement provided for the Government to take a 50 per cent shareholding in the field. The field is comprised of a double domed anticlinal structure containing two gas reservoirs at depths ranging from 2700 - 3000 m. Water depth is 110 m. The development plan called for two standalone steel platforms to be installed sequentially over a period of some years depending on gas demand. The first platform (MPA) was put in place in 1976 but difficulties were experienced with piling and drilling of the 12 (later increased to 14) wells did not start until 1978. First gas was piped ashore late in 1979.

Jan 1, 1994

By C. A. Cole

This work consists of research in cable fault location and the construction of four field-test units based on the research. Swept-frequency sounding of mine cables with RF signals has been the technique most thoroughly investigated. The swept-frequency technique is supplemented with a form of moving target indication (MTI) to provide a method for locating the position of a technician along a cable and relative to a suspected fault. Separate, more limited investigations involved high-voltage time domain reflectometry and acoustical probing of mine cables. Particular areas of research included microprocessor-based control of the swept-frequency system, a microprocessor-based fast Fourier trans-form for spectral analysis, RF synthesizers, transmit-receive switches, RF receivers, cable dispersion-compensation techniques, low-voltage multielement display systems, and techniques for injecting or recovering RF energy through cable walls in support of clamp-on fault locators.

Jan 1, 1982

1. Domestic Production and Use: In 1980, 13 companies operated 33 primary aluminum reduction plants, with 3 firms accounting for 62% of production. Washington, Oregon, and Montana accounted for 30% of the total production; Texas, Louisiana, and Arkansas 19%; Tennessee, Alabama, and North Carolina 15%; other central and eastern States 36%. Based on published producer prices output of primary metal in 1980 was valued at over $7 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Packaging accounted for an estimated 26% of domestic consumption in 1980, building 22%, transportation 21%, electrical 12%, consumer durables 7%, and other uses 12%.

Jan 1, 1981

Objective To develop safety training tools for mine health and safety trainers that fill gaps in currently available materials and help capture the wisdom and knowledge of “expert miners.” Background NIOSH began a series of stakeholder meetings in 1998 to determine what research was needed to improve miner health and safety. One of the more common concerns among stakeholders was a critical lack of appropriate training materials applicable to metal/nonmetal mining. Participants provided many insights into what effective training materials should include and how materials could best reach both new and experienced miners. The most important factors were that any materials be realistic and interesting and that some way must be found to capture the wisdom of expert miners before they retired. Approach NIOSH researchers chose videos as the best means of achieving these training goals. Over the past 3 years, NIOSH has produced three training videos that present information on safe work practices in underground mines: handling explosives, recognizing roof hazards and using proper scaling techniques, and installing ground supports. The last two videos, “Rock Falls—Preventing Rock Fall Injuries in Underground Mines” and “Miner Mike Saves the Day—or—Ground Support…It’s Important,” have won Alice Hamilton awards, NIOSH’s highest recognition of Excellence in Occupational Safety and Health, in the Educational Materials category. Two new videos are now being released. Both of these videos were shot completely in operating underground hard-rock mines and used expert miners to tell the story. Hazards In Motion The first, “Hazards in Motion,” deals with the dangers of working around mobile equipment in an underground mine. Ben, a new trainee, refuses to pay attention in his 40-hour New Miner Training class, and when the class takes its first trip underground, he wanders off and finds himself in many dangerous situations. He encounters many experienced miners who both chew him out for his unsafe attitude and give him advice and information on how to survive around mobile equipment. Many common pieces of equipment are shown, including haulage trucks, LHD=s, tracks and trains, slushers, skips and hoists, and air doors. The dangers of ignoring signals and of horseplay are also included. After nearly losing his life numerous times, Ben learns his lesson with the help of the Safety Angel, an experienced miner who looks suspiciously like his safety trainer. Ben’s Safety Angel saves his life repeatedly, teaches him how to work safely around these common conveyances, and introduces him to experts who have specific safety tips. Ben learns the error of his ways and vows to be the safest miner in the mine. “Hazards in Motion” is approximately 30 minutes long. Hidden Scars The second video is the first in the NIOSH “Expert Miner” series. “Hidden Scars” is a narrative interview with Don Capparelli, a miner and supervisor at the Sunshine Mine in north Idaho. This video captures the story of a fatal rock burst in May 1994, when Don was seriously injured and his long-time partner, Jimmy Findley, was killed. “Hidden Scars” is a very powerful story. Don Capparelli shares the physical and emotional pain he lives with daily as he relates the events leading up to the rock burst that took the life of his best friend and partner. This video is an excellent reminder of the human cost of uncontrolled accidents and the hidden scars that survivors must deal with for the rest of their lives. It runs approximately 25 minutes.

Jun 1, 2001

By M. Mononen, J. Huuskonen, M. Vauhkonen, J. Kourunen, A. Lehikoinen

"A new approach to measure process conditions in flotation cells is presented. Real scale flotation cells in a Zinc circuit are imaged using Outotec LevelSense sensors based on electrical resistance tomography. The latest results from long period plant tests show that the sensors together with FrothControl analysis give new information that correlates well with other process parameters. The sensors can compensate for electrical contact contamination using an automatic calibration technique and they are basically maintenance free. The results indicate that using the LevelSense sensors and FrothControl solution, the process control and optimization can be done automatically, stabilizing and improving the metallurgical performance of the flotation process.INTRODUCTIONThe froth flotation process is widely used in mineral industry for the separation of minerals from low-grade ore slurry. Different property parameters of froth and slurry could be measured to monitor and control the flotation process: air bubble size distribution, flow dynamics, thickness of the froth bed, amount of solids in the froth, etc. Some techniques already exist that can be utilized in studying these important parameters on-line. Examples of the techniques are the high-speed video imaging, simple conductivity probes, ultrasound techniques, floats and pressure transducers (Maldonado et al., 2008). These techniques, however, often suffer from some limitations. For example, the video imaging only gives information from the surface of the froth, simple conductivity probes suffer from contamination and the floats may get stuck and therefore do not give reliable signal for process control and optimization."

Jan 1, 2013

During the middle of this century, exploration and mining reached a low ebb in New Zealand. Tas McKee did his utmost to rejuvenate the mining industry, using the latest technology and an understanding of the environment far ahead of his time. Today, advances in the geosciences enable sophisticated exploration to proceed to the drilling stage before any significant environmental disturbance is created. Thereafter developments are now carried out with integrated management of the environment and rehabilitation so that disturbed land can be used for other purposes once mining is finished. Thus, we now have environmental engineers and scientists taking their place as professionals in our Institute.

Jan 1, 1987

By Don A. Toth

Until recently, the fire protection systems used to protect mining equipment were based on generically designed, off the- shelf concepts. These systems were reliant on single agent approaches and were generally comprised of a series of small twenty or thirty pound chemical canisters that would discharge their contents when triggered by thermal detection means. As the equipment grew in capacity, the logic used to increase the protection was to add more chemical canisters to the system. Hydraulic excavators and large-scale mining trucks grew dramatically in size into the 1990?s and beyond; with this growth came the increase in major losses due to fire. This was evidenced throughout this period, and continues to be of great concern today. During this presentation you will learn of the significant changes that have come about as a result of this history. Today, dual-agent products, infrared detection and unit-specific, engineered systems are the primary phrases used when discussing how to best protect this equipment from fire loss. This session is a must for anybody looking to optimally protect their equipment assets and for those looking to renew and/or secure new insurance for high value equipment in the future.

Apr 1, 2005

By D. F. Cooper, J. G. Paterson, K. H. Pang

"Effective control of metallurgy by manual adjustment of cell levels is common flotation practice. With an on-stream XRF analyzer interfaced to a process control computer it is possible to program the computer to carry out this function automatically. This paper describes the development and implementation of closed loop control of the concentrate and tailing grades at the Clarabelle Mill of the International Nickel Company of Canada, Limited, The XRF analyzer was used as the sensor, cell level as the control and the computer as the controller.IntroductionThe International Nickel Company of Canada, Limited recently brought on-stream Clarabelle Mill having a rated capacity of 35,000 tons per day. The plant was required to increase milling capacity in the Sudbury area by 9,000 tons per day and to improve milling efficiencies by replacing the obsolete crushing and grinding equipment at the Copper Cliff Mill. This represents the fourth mill built since 1959 and incorporates the latest thinking in a continuing evolution of instrumentation and control concepts. Table 1 illustrates control progress at Inco since 1959.In 1967 Frood-Stobie Mill came on-stream incorporating a central control room, an on-stream analyzer, a data gathering computer, and a significant change in instrumentation from direct-contacted pneumatic to miniature electronic. The computer successfully controls the analyzer but has very limited process control capability. Based on this experience a process control computer system was installed at Clarabelle Mill with the objective of carrying out extensive supervisory control and a limited amount of direct digital control."

Jan 1, 1973

By Oliver C. Ralston

The minerals that enter welding-rod coatings and fluxes are the main subject of this report. Few mineral producers know just what minerals and what grades and quantities of minerals are required by the welding trade, and it is for their information that this report has been prepared. The various methods of welding are discussed extensively enough to inform this type of audience. Specialists in welding probably will find little on welding that is of value to them, but they may learn something more about the minerals or mineral products that they use. The authors did not find it easy to prepare this publication, and any needed corrections will be welcomed. Regarding welding, research, Jenks4/ 1 points out that while the process of welding in simple in operation, the phenomena attending its use are extremely complicated, and the efficient and safe use of welding requires an understanding thereof. Although the fluxes and the coatings used have solved many problems, many other problems require the joint effort of the whole industry; therefore, it is hoped that this report will be found of practical value.

Jan 1, 1940

By Joseph Nawrocki, Margaret Hettinger, Dr. Catherine Johnson

"Optimized rock fragmentation is essential for minimizing downstream costs to mining operations.Photographic fragmentation analysis, vibration monitoring, and high-speed video all providemeasurements of blast effectiveness and supply data that allows operations to modify blasts to achieve downstream goals."

Jan 1, 2016

By A. Kale

A chlorination pilot plant having capacity to produce 5?10 kg/hr of titanium tetrachloride is in operation at the chlorination facility in Mintek. The bubbling fluid bed chlorination plant can be operated in batch and/or continuous process to study the chlorination kinetics of various feedstocks. The chlorination of titaniferrous ores to produce titanium tetrachloride (TiCl4) was carried out during the commissioning of the pilot plant and also as part of the titanium programme carried out at Mintek. TiCl4 is a basic raw material for producing commercial titanium dioxide pigment and titanium metal. This paper discusses the challenges faced during the commissioning and operation of the chlorination pilot plant. It also discusses the effect on the auxiliary facilities and instrumentation as a result of the harsh operating conditions of +1000°C and use of corrosive gases like chlorine and titanium tetrachloride. It discusses the effect of physico-chemical properties of the titanium tetrachloride and iron chlorides. The effect on the chlorinator refractory lining due to heating and cooling of the chlorinator is also discussed. Besides the special provisions made during the design of the chlorinator, this paper also discusses the operational experience and possible solutions to be implemented in future. Keywords Fluid bed chlorination, titanium ore chlorination, titanium tetrachloride (TiCl4) production using fluid bed technology.

Jan 1, 2011

By William G. Hedling

The operation of electric face equipment in underground coal mines has proven to be extremely hazardous to mining personnel, including equipment operators and others working in the vicinity of active equipment. Recent industrial engineering studies* of accidents and fatalities indicate that a major contributor to this hazardous situation is noncompliance with modern principles of human engineering, particularly lack of standardization of control configurations. Control configurations differ not only among different machine types, but also among the same machine types produced by different manufacturers. This lack of standardization can produce a high incidence of error in the operation of electric face equipment, thus creating a potential source of accidents. Other examples of non-compliance with human engineering principles are the widespread use of identical black, round control knobs (regardless of the function being performed), and the inappropriate location, spacing, and labeling of controls. Any or all of these factors may place the operator in a "negative transfer" situation, which means that control manipulations appropriate for one type of machine are different from (or even the reverse of) the control movements required to produce the same effect on other machine types. This situation increases the accident potential to the operator, as well as to others in the vicinity. Accident potential is further increased by circumstances which do not allow for large error tolerance-specifically, emergency procedures. Reports of accident statistics cite operator inexperience as a primary cause of most accidents involving underground electric face equipment. Several factors contribute to operator inexperience, including: 1. High personnel turnover 2. Employee absenteeism 3. Current union practice of bidding for jobs.

Jan 1, 1974

By Karl J. C. Harries

"12.1. NO DEPRECIATION/GAAPAll calculations and computations relating to the Royalty shall be carried out in accordance with generally accepted accounting principles consistently applied to the extent that such principles are not inconsistent with the provisions of this Schedule and the agreement attached hereto, it being specifically agreed that nothing herein contained shall permit, or be construed to permit, the Operator to deduct any amount for depletion, depreciation, amortization or any deduction that represents a non-cash outlay.Comment: In cases like net profit royalties where recoupment of prior expenditures is permitted, care should be taken to avoid any implication that depreciation may also be taken. It is only logical and equitable that Property Owners should not be permitted an apparent ability to “double dip” with respect to deductions. A provision like this example should accomplish the task. It will be noted that the example specifically contemplates that the negotiated arrangements will prevail over any requirements of GAAP. Accordingly, if the parties agree to an unusual formula for recoupment, it will not be set aside to accommodate GAAP requirements. Under GAAP, revenues and expenditures are accounted for on an accrual basis. In addition, it specifically prohibits the taking of non-cash deductions, which is in keeping with the concept of recoupment.Although in some ways the example states the obvious and could be considered redundant, its presence, especially in provisions contemplating recoupment, makes it clear to the financial people that there may well be some variations from normal practices dictated by GAAP, while at the same time confirming the availability of GAAP to fill any voids.The accounting profession often makes the caveat that application of GAAP is an “art”, not a “science”. GAAP do not provide a cure-all and can create problems that will have to be addressed. For example, GAAP contemplate that asset costs are to be reduced by investment tax credits, which can cause a problem for a payor with more than one mine."

Jan 1, 2003

By Steve Kral

The mining industry has waited a long time for the resurgence in commodity prices and demand for its products that it is now experiencing. Base and precious metals prices have reached levels not seen before. Coal prices have also shot up. And there are encouraging signs in the uranium market. China’s nearly out-of-control economic growth is said to be the leading driver for much of this resurgence. But demand for energy, metals and building materials in the United States and elsewhere are also major factors. The result is that expansions and new mines for nearly every commodity are in the works.

Jan 1, 2005

By Descour Jozef, Suguru Shirasagi, Takuji Yamamoto, Koji Murakami

For TBM tunneling no visual inspection of excavated ground is possible. This may hinder the high-speed excavation, particularly in complex ground conditions. The TBM Excavation Control System was developed for better prediction of geological conditions ahead of the tunnel face during excavation. The seismic reflector tracing produces volumetric images of anomalies in the ground in “near-real time.” These images are verified using logging data from pilot boring and TBM driving data, to improve reliability and precision of ground mapping. Also good correlation was obtained between the rock strength index computed from TBM data, and one derived from volumetric seismic images.

Jan 1, 2007

By John A. Herbst, Xiangjun Qiu

"Prediction of wear on a microscale level in mineral processing equipment turns out to be a challenging undertaking. This is particularly true for cases in which the objective is to use such predictions for wear parts design. The key to obtaining such predictions has turned out to be the use of physics based models along with phenomenological constitutive equations. In this paper, two components of the HFS tool set, one for particles (DEM) and one for slurry (MPF), are used for modeling. These tools are applied to the simulation of wear of SAG/AG shell lifters/plates and wear in slurry pumps. In each case wear predictions are validated with plant measurements.INTRODUCTIONHigh Fidelity Simulation (HFS) has emerged as an important tool set for mineral processing plant equipment design and optimization (Herbst and Potapov, 2003; Herbst and Nordell, 2002; Herbst and Lichter, 2006). This tool set consists of Discrete Element Modeling (DEM) of particle motion, Multi-Phase Flow (MPF) for liquid motion, discrete grain breakage (DGB) for particle fragmentation and discrete grain liberation (DGL) for mineral liberation (Campbell, Potapov and Tsuji, 1997; Ferzinger and Peric, 1997; Potapov and Campbell, 1996; Herbst and Potapov, 2005).Three sample snapshots of basic HFS illustrating the use of each of the various types of mineral processing equipment are shown below.Figure 1 shows a snapshot of a DEM simulation of ball charge motion in a commercial scale Vertimill. DEM simulation involves simultaneous solution of Newton’s Laws of Motion for 400,000 balls."

Jan 1, 2007

By C. G. Maier

Relatively infrequent use by metallurgists of the term "sponge chromium" as contrasted to more than occasional reference to "sponge iron" may be ascribed to the fact that the former material is not a commercial product, while the latter has been known and used, at least in one form (Swedish sponge iron), for several decades. It is doubtful whether a true sponge chromium ever has been prepared heretofore in the laboratory by more than one or two investigators. Nature presents a much. more difficult problem to the investigator endeavoring to make sponge chromium than pertains to the production of more easily reducible elements such as iron or nickel. Recent widespread interest among metallurgists in the possibilities of powder metallurgy is ample incentive to explore the feasibility of producing pure chromium metal in finely divided form. The shift in terminology of this statement from "sponge" to the "finely divided form" is deliberate in emphasis of distinction between terms that occasionally have been used loosely. It would seem desirable that a uniform usage descriptive of finely divided metals be adopted. While to some it might seem preferable that the terra "powdered" metal be reserved for a finely divided form produced by mechanical means, as, for example, chromium produced by the mechanical comminution of electrolytic sheets or flakes, current usage of the term "powder metallurgy' involves no distinction as to source type of material. It is usually accepted, however, that a sponge metal is one reduced from oxide or other combined form at temperatures below the melting point of metal or oxide so that the particles of metal are pseudomorphic, at least macroscopically, with the source material, and, in consequence of the loss of material without change of external shape of the particles necessarily have an open, porous, or "spongy" structure.

Jan 1, 1942