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By A. Uribe-Salas, J. A. Finch, B. J. Huls

Gas holdup profiles in the collection zones of a pilot flotation column (0.91 m x 13.5 m) and a laboratory flotation column (0.057 m x 9.5 m) operated with air and water only were determined from pressure measurements. The profiles were determined discretely and continuously. For the pilot column, a minimum distance between pressure measurements was necessary to give reliable results. For the laboratory column, a third-degree polynomial fit to the pressure vs. height data was required. Water manometers proved to be less sensitive to sensor and process noise than pressure transducers. The profiles showed that gas holdup approximately doubled over a height of 8 to 10 m. The profiles were not linear, and the gradient increased towards the top of the column, especially for gas rates greater than 1 cm/s. The profiles cannot be predicted by a simple bubble expansion model. The implications of this new finding of a significant gas holdup increase with height in the collection zone on various aspects of flotation column design and operation are discussed.

Jan 1, 1996

By Sam M. Pickering

Most high, purity silica is produced from crystalline quartz-generally from sand. However, there is a small area of southern Illinois where a porous, friable white chert rock is found which is very different in physical form from quartz sand. This microcrystalline material, commonly referred to as tripoli, is more easily ground to micron sizes than sand. Although of similar Moh's hardness, microcrystalline tripoli is less abrasive than either ground quartz sand or many synthetic abrasives. Location The southwestern corner of Illinois is underlain by extensive deposits of very porous chert; in some places the material is quite white. Two companies - Illinois Minerals Co. and Tammsco, Inc. - mine and process this white material. The Illinois Minerals plant is located at Elco, and the Tammsco plant is in Tamms, Illinois. Both companies mine from various locations within a ten mile truck haul of their plants. Production from this district has been continuous since at least 1915. Malvern Minerals Company mines and processes a generally similar microcrystalline, friable novaculite near Hot Springs, Arkansas.

Jan 1, 1985

By L. B. Bramlett

The Archean (2.65 b.y.) aged Canning Stock at Copper Mountain, Wyoming contains an average of 20 ppm U. The North Canning and Fuller deposits occur within the enriched interior of the stock. Post-Laramide development of super gene enrichment blankets occurred in wide (25- 100 m) crushed zones. Hematite and chlorite accompany pyrite and sooty pitchblende in the mineralized zones. Reduction mechanisms proposed for deposition of pitchblende are: 1) sulfides, 2) hydrocarbons, 3) bacteria, 4) the water table, or 5) some combination of these. Abundant tar- type organics appear to have preserved the enrichment blankets from degradation. Trace element and radiometric data define target zones, but exploration models focus on favorable structure.

Jan 1, 1980

By A. Guzman

The design and construction of a new 140-ton-per-day R. O. M. phosphate rock scrubbing and washing plant was undertaken by Western Knapp Engineering Company, a Division of Arthur G. McKee and Company, for the J. R. Simplot Company, Minerals and Chemical Division, Pocatello, Idaho. The new plant replaces the owner's existing facilities at Conda, Idaho, seven miles northeast of Soda Springs in the southeast corner of Idaho. Replacement of the existing facilities became necessary because of loss in production and recovery. These losses were due in part to varying grades of raw ore from the mine and to the type of process equipment used in the old plant to upgrade the ore. Increase In production and grade was further necessary by demands created by expansion of facilities in Pocatello, Idaho, where all process ore from this plant is shipped. The new process scheme includes an ore-feeding system, scrubbing, screening, classification, wet cycloning, attritioning, filtering, drying, storage and shipping facilities. Space was also left for future increases of scrubbing and classification capacity and for heavy media separation. It is the purpose of this paper to take up some of the considerations necessary in the design of small mills in order to achieve the desired objectives of a successful plant, such as production, minimum operating cost and maintenance cost.

Jan 1, 1969

By Phil D. Newman, Robert J. Pine, Kevin Ross

The Stratoni Operations in northeastern Greece rely on a selective backfill method to exploit high-grade lead-zinc deposits. Underhand cut and fill often results in spans approaching 6-9 m (depending on the mining method employed) and a competent backfill is required to avoid dilution problems. Cement consumption represents a significant mining cost and through improving the control of the backfill batch preparation, the cement content could be greatly reduced without jeopardizing the grade control. A new distribution system was installed and a QAIQC system designed in cooperation with the operators to allow a wide range of backfill recipes, providing cost savings to the mine. A review of possible failure modes and the consequent strength required for the chosen mining method was also completed and indicated potentially significant cement content reductions. The calculations are supported by 12 years of experience at the mines which provides a valuable insight into the applicability of the approach developed.

Jan 1, 2001

By Roberto Pimentel de Souza

CURD started producing pellets in 1969, with one two-million ton straight grate plant. In the beginning of April '73, the second unit came on stream with an additional capacity of 3 million TPY of pellets. In January '77, the third unit started, bringing the annual capacity to 8 million TPY. For the present year 3 more units, 3 million each, are expected to begin production. CVRD's experience is given about the use of different binders and additives. Over the years several kinds of pellets have been produced to satisfy the market requirements. General quality information is given regarding each.

Jan 1, 1978

By S. P. Brown, J. E. Worthington

Increasingly, exploration geology seems to be growing into a practice overly separated from production geology, yet the eventual purpose of exploration is a producing mine. To help in the search for new deposits, exploration "lessons" will be drawn from the papers given at the Fall AIME Applied Geology Symposium. In addition, examples will be re-emphasized to show how early observation of matters now routine to mine work (for example, hydrology, rock mechanics, oxidation state) can help increase the effectiveness of exploration.

Jan 1, 1992

By R. K. Mehta

Existing acid mine drainage treatment techniques are not remedial In nature, i.e. though heavy metals can be removed from acid mine water, their presence in tailings and large quantities of these tailings tend to increase capital and operating cost for tailing management. This paper presents the results of a series of systematic tests which finally resulted In the development of the "ferrite" process for mine drainage of coal operations at ambient temperature. The role of pH, temperature, quantity of ferrous salt addition and degree of oxidation is investigated targeting the production of high emu spinel ferrites and effluent water complying regulatory standards with respect to Iron. manganese suspended solids and pH.

Jan 1, 1992

By H. L. Holden

The single line grinding circuit at Bond Gold's Colosseum mine consists of variable speed drive semi-autogenous (SAG) milling and secondary grinding with a fixed speed ball mill. There are several advantages and disadvantages of operating SAG mills with variable speed drives. Discussion in this paper will focus on the effects of variable speed SAG milling in relation to mill liner wear, grinding media consumption, and mill operating availability. Operating experiences, corresponding mill data, and pertinent design changes are also presented.

Jan 1, 1991

By C. Roos

"Nearly every input to a mine plan is based on an estimate. The estimates may be from sample data, historical information, models, or personal opinion, but in all cases, these values are simply expected values (means). In real life, we do not get to iterate the exact conditions at our mining operation many times to ensure that that average value is attained. The expected value also tells us nothing about the spread of values that that input might take on. The result is a significant amount of unquantified uncertainty in our mine plans. Unfortunately, it is often too expensive or time consuming to update planning processes and software. This paper presents a proof of concept spreadsheet scheduling tool that can be utilized to incorporate many geologic realizations (simulated models) into the mine scheduling process. While this POC is not intended to be a detailed model of uncertainty, it is to show that there are stepping stones available for mine planners to begin to embrace uncertainty and produce more achievable plans without requiring a significant change in their planning process. INTRODUCTION Mining companies have included quantifying uncertainty, or at least risk, as a requirement of project justification for many years, however many times this process lags behind the traditional mine planning process and the results are rarely used to improve the plan. Nearly every parameter used in a mine plan is an estimate and the mine planning engineer should recognize and even embrace the inherent uncertainty in those parameters and its effect on their forecast results. While many of the uncertainties are beyond the scope of the traditional mine plan (e.g. global market uncertainty, socio-political uncertainty, environmental uncertainty), some uncertainties can, and should, be included in the mine planning process. Many mining engineers have incorporated techniques such as Monte Carlo Simulation or Discrete Element Simulation to understand the range of productivity that can be expected for an operation but most still rely upon one estimated model for what is likely the critical component of technical uncertainty, the geologic resource. Modern geostatistical methods can provide multiple ore body realizations to provide a thorough unbiased “picture” of the geologic uncertainty but most traditional mine planning techniques are not formulated to allow for multiple (100-200) realizations of each material quality/grade parameter. Commercial software companies and research groups are progressing with development of tools that can incorporate geologic uncertainty, and even optimize extraction plans in the uncertain environment. Unfortunately, this author believes that a significant number of mining operations will not be able to adopt these techniques due to the computational requirements of the advanced techniques and the costs associated with implementing proprietary software. In an attempt to encourage mining engineers to embrace the inherent uncertainty in their mine plans, this paper presents a cost-effective alternative that can be developed in-house, at any mine, to schedule mid to long-term mine plans while continuously monitoring the uncertainty in the results. The author hopes that by demonstrating the usefulness of such a system that mining companies will encourage engineers, geologists, and geostatisticians to find ways to incorporate this powerful data into their processes and procedures."

Jan 1, 2017

By H. W. Judges

A 16.5-kt/day underground molybdenum mine is being developed at Questa in Northern New Mexico by Molycorp, Inc., a wholly-owned subsidiary of Union Oil Company of California. Construction of the underground mine began in 1979, and first production is scheduled for early 1983. A gravity block caving method has been selected for mining the ore. Access to the mine will be through a service shaft, development shaft, and a conveyor decline. The shafts are being sunk under contract and the conveyor decline is being driven by Molycorp. The driving of the decline began in February, 1979 with a 10-man mining class. By the first of May, enough men had been trained to begin a continuous operation and by March 1, 1980 the face had reached the 1500 m mark. The heading is being driven with trackless rubber-tired equipment using a three-boom drill jumbo, 2.7 m3 LHD units and 7.3 m3 trucks. Ground support has been by rock bolts and wire mesh, followed by Fibercrete. A 16.5-kt/d underground molybdenum mine is being developed at Questa in northern New Mexico by Molycorp, Inc., a wholly-owned subsidiary of Union Oil Company of California. The new $200-million underground project will revitalize mining and milling activity at Questa, where small scale underground mining first began in 1920. Large scale open-pit mining was initiated in 1965 but now, because of the high stripping ratio, surface mining is being phased out. Construction of the underground mine began in 1979, and first production is scheduled for early 1983. The company expects full capacity - 9 Gg of molybdenum per year - to be reached in 1984.

Jan 1, 1980

By N. B. Prenn

Many recent projects have been developed and mined based upon imaginary reserves. Imaginary or "geo-fantasy" reserves have cost many companies millions of dollars. The significant and varied technological advances in the mining arena have done little to curb reserve calculation problems. These advances may have served to increase the prevalence of reserve problems by putting more tools in the hands of personnel not properly trained or experienced in reserve estimation. This paper will discuss potential problems related to calculating reserves, which include: SAMPLING ERRORS -obtaining a representative sample. -Decay analysis of wet RC drilling -Bias introduced by sample preparation. -Assay bias; Coarse gold. -Specific gravity samples. GEOLOGICAL ERRORS -structural boundary definition. -Separation of high grade and low grade zones. -Incorrect continuity assumptions MODELING ERRORS -Too much influence of high grade samples. -Improper method of calculation. -Assumed range of influence. -Errors in the data. ENGINEERING ERRORS -Inaccurate assumptions. -Inadequate metallurgical testing. -Designed bottlenecks.

Jan 1, 1992

By R. E. Nivens

In the past, Newmont Gold Company relied on cement for their ore agglomeration process. With assistance from Betz Industrial, Newmont began Investigating the use of polymers for ore agglomeration. If gold recovery would not be jeopardized, then polymers could replace cement and possibly reduce operational costs associated with cement agglomeration. The following outlines the preliminary testing conducted to determine the feasibility of polymer agglomeration with Newmont's ore and the results of the test heap, which was constructed so the program could be examined under actual operating conditions. Similar polymer agglomeration testing has been successfully performed in other Nevada gold operations. By eliminating the need for cement, a polymeric agglomeration program could improve material handling operations, as well as offer the following additional savings. First, the polymer application uses only lime for adjusting basicity, the polymer does not contribute any alkalinity to the heap. Because lime is more soluble than cement, detoxification of the heap becomes much faster and less costly for the mine relative to rinsing cement alkalinity. The following graph compares the detoxification rate of cement and polymer over a 33 day cycle.

Jan 1, 1993

By Nomuqhele N. Nkosi, Yasuo Yabe, Musa D. Manzi, Raymond J. Durrheim, Siyanda B. Mngadi

This study examined rock failure in brittle rocks hosting the deep gold-bearing ore bodies on scales between millimeters and kilometres. This research study is part of the International Continental scientific Drilling Program (ICDP) project, “Drilling into Seismogenic Zones of M2.0-M5.5 earthquakes in deep South African gold mines” (DSeis). The broader ICDP-DSeis project aims include the examination of the extent of damage, the stress state around the fringes of the earthquake, and the potential existence of living organisms associated with deep-level earthquakes. Nevertheless, this study focused on two seismogenic zones – the Cooke 4 mine and Moab Khotsong mine. At Cooke 4 mine, the study examined the evolution of mining-induced fractures (M1-4) occurring ahead of the stope face during the extraction of the remnant shaft pillar. These fractures were monitored and delineated by a dense array of acoustic emission sensors that allowed hypocentres to be located with decimeter accuracy. Using this acoustic emission data, the DSeis team drilled and recovered the fractures, rock breccia and gouge using a sophisticated triple-tube drilling rig.

Apr 26, 2022

By William M. Warren

Recent sinkhole activity in carbonate terranes of Alabama has resulted in damage to transportation lines, structures, utility lines, and property in general. Active sinkhole development and subsidence has been well documented in Alabama, Florida, Pennsylvania, and South Africa. An excellent example of the potential danger resulting from this activity is the spectacular collapse under a South African gold ore crusher plant that resulted in the death of 29 men in 1962. Due to the severity of the problem in certain localized areas in Alabama, a detailed investigation is being undertaken by the Geological Survey of Alabama and the U. S. Geological Survey. One of the most promising techniques is the application of aerial photography and thermal infrared imagery. Conventional and modern remote-sensing techniques are being used in Alabama to locate and define areas of sinkhole activity and to determine which areas are most prone to its occurrence.

Jan 1, 1975

By T. S. Golosinski

Typical dragline rigging includes several sets of ropes: hoist ropes, drag ropes, dump ropes and boom suspension ropes. The drag and hoist ropes contribute most to the dragline operating cost, and significantly influence dragline productive time. Both work in very difficult conditions and wear out rapidly. As a result frequent rope changes are required at a substantial cost and time loss to the operation. Although performance of rigging has a profound impact on dragline performance, there are no industry-wide standards related to its selection, operation and maintenance. Little information on the subject is available and the practice differs widely throughout the industry. The life of drag and hoist ropes depends on: (1) rope construction, which should closely match requirements of the specific application, (2) correct definition and application of the rope discard criteria, so that full advantage of the rope can be taken without endangering safety of operation, and (3) rope operating conditions and its maintenance. The study presented in this paper was intended to address the above points, based on a survey and assessment of the present industry practice.

Jan 1, 1993

By P. Moyo, S. Dixon, R. Norcross

The separation and recovery of copper from cyanide solution has been investigated since the early 1900s. The precipitation of copper using sulfide ion was patented in 1911 by Williamson, published by Leaver & Woolf of the USBM in 1931 and Cyanamid in 1960s. The current practice of sulfide precipitation is used in various processes such as “SART" for cyanide regeneration and copper recovery. The precipitation of copper sulfide requires the pH of the clear solution to be in the range of 4-6. The precipitated copper sulfide can be sold to smelters. Alternatively, copper cyanide can be precipitated from clear solutions in the pH range of 2-3. However, selling copper cyanide is challenging because of its cyanide content. Past work has focused on the use of boiling sulfuric acid to convert copper cyanide to copper sulfate as published by Seracini in 1991. This paper describes a simple process to convert copper cyanide to copper oxide using sodium hydroxide at ambient temperatures. The cuprite can be sold to smelters or used as a feed to an electrowinning circuit to produce copper cathodes. The process provides an effective method to recover copper from cyanide solutions with a lower capital requirement.

Mar 2, 2022

By Michael Lenz

Predictive maintenance technologies including vibration analysis, tribology, infrared thermography, ultrasonic detection, and electrical measurements have been applied to large electric mining shovels. The predictive program was initiated on the P&H Model 2300 and 4100 electric shovels. The utilization of these technologies has shown the potential for improving electric mining shovel availability and minimizing maintenance costs. Predictive technologies provide the tools to assess machinery condition. Availability is enhanced by the condition based planning of component replacement. Maintenance costs are minimized by focusing resources through condition based prioritization.

Jan 1, 1997

By Ralph L. Merklin

One of the most commonly employed set of calculations in mill design and research is the material balance, known in wet beneficiation plants, as an Ore and Water Balance. For mill designers, the balance is one of the principal requirements in determining the proper size of launders, pipelines, process equipment, etc. In process development, one of the major goals is the establishment of an optimum balance. The usual procedure for calculating a material balance involves a manual technique utilizing reference tables, pre -obtained data, and a slide rule or desk calculator. With these, the engineer must perform a series of calculations which are repetitious in nature and time consuming. Figure I is the flowsheet of the grinding and flotation circuits for a copper concentrator. The initial ore and water balance was calculated manually and required approximately 24 manhours. Later, a number of changes were made in the balance, each of which required an average of 8 manhours.

Jan 1, 1967

By Ronald W. May

The Lower Cretaceous McMurray Formation in northern Alberta contains bituminous sands interbedded with other sediments which form the reject encountered during mining operations. Grade prediction is based on a combination of geological interpretation, computer modelling and past mining experience. In addition to estimates for ore, an accurate estimate of "waste" or "reject," are required for Mine Planning. This study investigates the ability of point-kriging using geostatistics, to augment the existing data base of drill-holes in a study area on Syncrude's leases. This approach enables the assessment of potential "worst" case - "best" case scenarios within the context of Mine Planning.

Jan 1, 1985