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By Thomas Mütze, Petya Atanasova, Kai Bachmann, Urs A. Peuker, Thomas Leißner

"A method is presented for the evaluation of mineral processing by liberation and upgrading. The method bases on the plot of recovery of valuables versus the recovery of gangue (Fuerstenau upgrading curve). The locking curve of a feed material was plotted together with the upgrading curve in a Fuerstenau diagram. The assessment of liberation and upgrading is done by a comparison of surfaces formed by the curves and some characteristic lines of the diagram. This plot allows the calculation of two new quantitative measures for liberation and upgrading. Both parameters can be combined to a third parameter describing the quality of the whole technical setup for mineral processing by subtracting the upgrading parameter from the liberation parameter. The third parameter shows a positive value in cases of upgrading determined processes, a negative value in cases of liberation affected processes and about zero for processes affected equally by liberation and upgrading. Thus it is easily possible to distinguish between poor results in the mineral processing caused by insufficient liberation or poor results caused by insufficient upgrading. Preliminary results from two case studies, performed on two different ore types, are very promising illustrating the practical use of such an approach."

Jan 1, 2014

By P. R. Pereira

This paper presents a comparison between the simulations of a semi-empirical model and a theoretical model for the prediction of radial stress in rock. The results of the simulations were compared to the results of a field test. The comparison of the radial stress predictions shows that in the semi-empirical model use of the plane wave approximation as the basis for the prediction of the radial stress provides a much better result than the theoretical model. The theoretical model includes the correct elastic wave geometry and theory but fails twice, firstly by considering the charge as a point (unit) energy source therefore; and secondly by using a Delta function with a very sharp rise and decay time to simulate, with no distinction between non-linear and linear zones, the attenuation of the energy per unit volume at the shock wave front as the wave moves away from the borehole. The results of the semi-empirical model were within the same order of magnitude as the results from the field test whereas only one result from the theoretical model came close to the result of the field test. However, even this closer result for the theoretical should be taken with caution as there was no measurement in the field test made at this distance from the borehole. Finally, because of its potential portability, convenience, and cost-effectiveness the theoretical model can be a most valuable tool for mining and civil construction operators in the early design of blasting rounds and of the mining operation itself.

Jan 1, 1993

By J F. C L Costa, J C. Koppe

It is recognised by the major international codes that resource classification involves the interaction of numerous qualitative and quantitative criteria such as data quality, geological and grade continuity, etc. However, the difficulty in quantifying the degree of uncertainty associated with mineral resources estimation has led to the creation of a large suite of methodologies, terms and definitions, with almost every mining company having its own set of standards. It is also intuitively known that several traditionally used methods to evaluate resources do not take into account the spatial continuity of the grades, being unable to provide a reliable measure of the error associated with their estimates. Since they do not provide an error assessment, these methods are inappropriate to assess local or global uncertainty associated with an estimate. Faced with these problems, this work aims at developing a methodology for either quantitative or qualitative analysis of mineral resources estimation, through incorporation of uncertainty and the correct definition of the associated risk or error. The proposed methodology includes the development of a software code incorporating all the main classification techniques used by the mineral industry. A comprehensive study about each technique was conducted allowing a comparison of the parameters affecting mineral inventory assessment. A case study was conducted with a typical iron ore deposit data set from the Conceitpo mine of the Itabira Complex in the Iron Quadrangle, Brazil. The results showed the specific limitations of each classification system and the influence in selecting their key parameters, always based on subjective choices.

Jan 1, 2009

By S. Suzuki, Y. Maeda, N. Wakamatsu

"A new pyrometallugical technology, named KLS process, has been developed by Dowa Mining at its Kosaka Smelter to smelt various kinds of lead raw materials.The process consists of clearly separated two reaction steps, smelting and reduction. For this purpose, respective stationary furnaces are installed which are connected by a slag launder.Dry raw materials, together with pulverized coal and oxygen-enriched air, are injected through a lance pipe into the molten slag in the first furnace. It is kept under a high oxygen potential to remove sulfur completely. Resultant PbO rich slag overflows to the second furnace where pulverized coal and insufficient air are also injected through a lance pipe to reduce PbO to lead bullion and to compensate for thermal deficit. The entire operation is carried out continuously. The process development started back in 1981. In late 1986, a pilot plant with a capacity of 3.5t/H was constructed.Already nearly 20,000 tons of raw materials, mostly lead sulfate mixtures have been smelted successfully.IntroductionFor a long time, main raw materials for lead smelting at Kosaka smelter have been such secondary incombustibles as lead sulfate and lead-barium sulfate. The former is leach residue of the copper smelter flue dust and the latter originates from Iijima zinc refinery. While the most of lead concentrates produced locally has been smelted by an ISF of Hachinohe smelter in which Dowa Mining has a share.The surplus lead concentrates were processed at Kosaka by a hydrometallurgical method to convert PbS to PbSO 4 as pretreatment, and followed by simultaneous smelting together with the above secondary materials (1). Approximate output has been 1,5000 /M of lead bullion and slightly more than 2,000t/M of refined lead by adding lead bullion returned back from Hachinohe smelter (2)."

Jan 1, 1988

By Shonn K. McNeill, Joshua Micah Hoffman

Security engineering is similar to other forms of engineering – the design is guided by the loads, materials, and desired function. For facility design, the load is the threat. Facilities that are designed with considerations for explosive hazards are designed with a shot, or series of shots, of a given size and distance from key locations. These facilities range from office buildings and industrial sites in developed nations to military and police stations in contingency areas. The challenge is the design shots are not often communicated to facility owners and managers. If the hazards change, whether it’s due to an increased capacity to cause damage by a threat or a decrease in capacity by a structure, not knowing the design shot means not knowing if security design needs to change. Blast modeling is an engineering tool that can be used to reverse engineer what a facility is suitable for, as well as be a tool for modifying security design for new conditions. This paper will examine military and civilian examples, including a case study of a military facility that did not know their as-built conditions and had to be rapidly closed; due to the determination their security engineering shortcomings could not be mitigated.

Jan 1, 2019

By F. K. Mulenga, M. Lusambo

"Geometallurgical models are a strategic tool used primarily in planning, diagnosis, and process optimisation. This paper discusses the development of a predictive model for flotation recovery at Kansanshi concentrator in Zambia as a function of key operational parameters. Daily data for milling and flotation from the circuit processing the copper sulphide ore was analysed. This data, recorded over a period of one year of production, was collected from diverse sensors measuring semi-autogenous milling and flotation parameters. Statistical analysis showed that copper head grade, acid-insoluble, and acid-soluble copper, SAG mill throughput, ball mill load, and tonnage of feed material to the SAG mill in the -125 +63 mm size fraction contributed to the prediction power of the proposed empirical model by as much as 90%. Finally, a proposal was made for the development of a simulation model under MODSIM®, a flexible tool for mineral processing applications. This was to test the limitations of the empirical model for future refinement. IntroductionKansanshi is the largest copper mine in Africa and the world’s eighth largest copper producer, with a total of 253 272 t of copper produced in 2016 (Newall, 2017). It is located approximately 10 km north of Solwezi, the capital and administrative headquarters of the North Western Province, Republic of Zambia. The ore deposit consists predominantly of chalcopyrite and malachite with variable amounts of chalcocite, bornite, chrysocolla, and azurite. Because of the varying proportions of sulphide and oxide copper minerals, the ore is classified into three distinct categories: sulphide, mixed, and oxide ores. As such, three separate processing circuits are used to mill the ore down to a standard targeted grind size of 80% passing 150 µm before froth flotation and leaching.A lot of research and development has been done to improve the performance of the sulphide ore circuit at Kansanshi. Despite the research efforts and subsequent operation, the sulphide ore circuit did not attain the target recovery and grade for 2016, primarily because of the complexity of the orebody.The constant drive to achieve the set production target of recovery and concentration grade after froth flotation motivated the development of a tool for the prediction of recovery. The anticipated benefit is not only to enable the plant to apply corrective actions when needed, but also to make a tool available for the quick assessment of the plant performance of the. For that purpose, data spanning June 2016 to May 2017 was analysed, cleaned up and curvefitted to an empirical model. In doing so, key parameters were determined and calibrated to represent the behaviour of the plant."

Nov 1, 2018

By Yerkezhan Madenova, Kairat Kalmurzayev

This study intends to demonstrate the engineering application of ground penetrating radar (GPR) that would enable site engineers to prevent the high cost of blind drilling. At the tailing dump located in Zhairem Mining and Processing Plant, the challenge of sheet pile driving is encountered due to the indefinite watertight clay layer deposition depth that serves as a protective layer against groundwater contamination. A numerical model of the soil underlying the tailing dump is built using the existing hole data to compare and confirm the existing geological cross sections for three profile lines along the south and southeast parts of the tailing dump. GPR is employed to investigate the subsoil geological structure and detect the watertight clay layer deposition. On the basis of radargrams tied to the existing borehole data in the numerical model, 21 drill hole locations are suggested to assess and confirm the clay layer depth along profile lines at the tailing dump. The drilling results of the suggested holes confirmed the expected depth of the clay layer. It is concluded that GPR is a practical and economic subsurface mapping method that can prevent the high cost of blind digging of the ground and orient the drilling operations effectively.

Jan 12, 2023

By B Murphy, N Strong, J Albrecht

Rio Tinto’s Argyle Diamond Mine has a history of underperformance with delivery of ore from the underground operation to the surface for processing with no real clarity in sources of loss and value. In order to increase underground production performance, the basic concepts of the Theory of Constraints model were applied to the Argyle underground production system. This prompted a revised view on bottlenecks and contributors to value loss and ultimately leading to record breaking mine performance. System loss reporting to demonstrate the best opportunity to drive value, departmental detail to develop tools to identify improvement opportunities and clarity across the team to ensure alignment and clear lines of communication were critical to the project success.

Mar 15, 2021

By W. C. Sanborn

The Bureau of Mines program of investigation and development of domestic mineral deposits had as its wartime objective the most effective immediate utilization of these resources in the interest of National security. Since the war, the results of individual projects are being prepared for publication as rapidly as practicable. Numerous chromite deposits were examined, among them those of the French Hill Mine in northern California. Situated 16 miles east of Crescent City, 76 miles from the nearest railroad shipping point at Grants Pass, Oreg., this deposit had a recorded yield of about l4,000 tons of metallurgical-grade chromite to the end of 1943. By the end of 1946, total production was more than 25,000 tons, averaging 43 percent Cr2O3, with a chrome:iron ratio of about 2.5:1.

Jan 1, 1948

By A. H. Duffield

"Forming part of the Prairie Evaporites, the sylvinite layer mined at Alwinsal underlies the Blairmore quicksands and the water-bearing Devonian formations. Production is achieved by a method of trackless, continuous mining of rooms, leaving pillars for natural support. The paper describes the development of the mine, and the equipment and organization employed in the operation and maintenance of the underground facilities."

Jan 1, 1972

By Zhiqiang Zhou, Libin Zhu, Zizong Zhu, Hao Xiong, Yuchuan Ding

In order to utilize the lean ore resources from XinJiang rationally and optimize mixture, laborarory measurements have been carried out under different basicity, various mixed carbon content as well as the properties (ratio) of fuel particle size by the sintering pot for further microstructure analyses. The results show that sinter strength falls by 5.0%, low temperature reduction disintegration index (RDI) drops off to the lowest in certain ranges. The natural degradation index of sinter is much higher when sinter basicity is between 1.65 and 1.75. The sinter strength increases when sinter basicity is between 1.75 and 2.0. Meanwhile, the sinter strength and RDI +3.15 improve with increasing carbon content. And the sinter strength and RDI+3.15 both decrease with the decrease of the distribution ratio of small fuel particle, thereby decreases the yield of sinter. Microstructural analyses have been investigated to figure out the mechanism of the influence of the three factors on sinter.

Mar 1, 2017

By Richard L. Sanford

This paper summarizes the results of the development of a Directory of Computer Programs Applicable to U.S. Mining Practices and Problems. The Directory is funded by the U.S. Bureau of Mines and includes a sampling of computer usage in operating and manufacturing companies, consulting firms, computer companies, research organizations, universities, and various U.S. government agencies. General references to computer applications throughout the mining industry are discussed as well as the availability of programs to interested organizations or individuals.

Jan 1, 1978

By Samer Rabab’ah, John C. Niedzielski, Jason Valeria

The PHX Sky Train is an automated people mover system located at Phoenix Sky Harbor International Airport. Phase II of the PHX Sky Train includes the design of over 150 drilled shafts for support of four guideway abutments, 75 guideway piers and three proposed stations. The soil conditions in this area generally consist of alluvial Sand, Gravel and Cobbles (locally known as SGC) deposited by the nearby Salt River. The foundation system will support relatively high axial loads, lateral loads and moments due to the height of the elevated guideway above the ground surface, where it needs to pass over roadways, parking lots, an existing terminal, and other buildings. Deep foundation design involves designing drilled shafts within the SGC deposits, some of which extend below the long-term groundwater table. Such extreme design loading conditions, together with difficult ground conditions at the site, result in several challenges for the design and construction of the deep foundation system for the project. This paper will present the results of a drilled shaft load test program implemented to provide site-specific measurement of the axial and lateral performance of the project drilled shafts. The load testing program consisted of a bi-directional load cell axial load test and a lateral load test performed on an instrumented test shaft 84 inches in diameter. The development and execution of the load test program and analysis of the test results are discussed. Comparisons were developed between predicted load capacities of drilled shafts using different design methodologies and the load capacity measured from the load tests. The load test results showed that underestimation of the capacity is evident using conventional methodologies. The load testing program was important for verifying the performance of the drilled shaft foundations on the project and was used to reduce the size of the drilled shafts. INTRODUCTION The PHX Sky Train is a five-mile long automated people mover system situated at-grade and on an elevated guideway which connects terminals, parking facilities, a rental car center and the Valley Metro Light Rail system in Phoenix. The purpose of this automated train system is to provide a secondary transportation system within the airport to relieve roadway congestion, minimize wait times and travel times for passengers and provide climate-controlled waiting areas. Phase 1 opened to the public on April 8, 2013. Phase 1A opened on December 8, 2014.

Jan 1, 2019

By B. Briggs

Over the past 15 years, the tunneling industry has pushed towards a higher degree of mechanization in nearly every phase of construction. The overall objective of the mechanization was to increase production and the level of safety in tunnel operations. However, the overall complexity of some systems have been a hindrance to a seamless transition to the newer technologies as increased maintenance requirements and re-training of skilled workers has altered the benefit curve for some innovations.

Jan 1, 2010

By Toshihiko Emi

The quest for cleaner steel is driven by increasingly stringent requirements from the manufacturing and construction industries. Key issues are the occurrence and removal of inclusions; These are discussed in the context of the unit processes of deoxidation, refining, transfer and casting of molten steel. Process thermodynamics and kinetics are also discussed. Recent progresses achieved and problems yet to be solved are elaborated, and an integration of the unit processes into a system to produce extra clean, steels with better performance is presented.

Jan 1, 1999

By D La Rosa, D Bennett

"Exploration drill core provides for a number of standard measurements essential for determining the viability of a new mine or the extension of an existing one. Rock lithology and alteration can be visually determined and grade measured from the half core. Geotechnical parameters such as rock strength and structure can also be measured. Using suitable proxies, these metrics can then be used to estimate run-of-mine (ROM) particle size. In combination with comminution test results, these can subsequently be used to design comminution circuit configurations and estimate their performance.The Frieda River Project drill core for the large Horse-Ivaal-Trukai copper-gold porphyry deposit was unusual due to a late stage gypsum-anhydrite stockwork event that overprinted much of the deposit. Above the base of the oxidised zone, which closely matches the water table, gypsum and anhydrite has been leached out, effectively removing the glue holding the rock mass together. As a result, much of the rock above this gypsum-anhydrite surface is fragmented and gravel-like in texture, while the material below this horizon is typically uniform and competent.Large volumes of the orebody above the gypsum-anhydrite surface are expected to need minimal or no blasting for efficient excavation. In addition, the fragmented nature of much of the material was expected to reduce comminution specific energy as it already appears as though it has been crushed. While this was expected to have positive impacts to the operation, the lack of standard geological logging methods available to accurately define the degree of in situ fragmentation led to difficulty in gaining certainty over the ROM product and grinding circuit feed size distributions.Using the extensive library of core photos for the project, a novel method using image analysis techniques to take both the intact core and gravel into account to predict ROM fragmentation was developed. In addition, existing point load test data was used to infer the strength of the rock and its impact on the blasting, crushing and grinding processes. The novel approach allowed development of ROM size distribution data and improved certainty in the results of comminution circuit designs.This paper describes the methodology undertaken in detail, and discusses the results obtained.CITATION:Bennett, D and La Rosa, D, 2016. The Frieda River Project – a Novel Approach to Analysing Exploration Drill Core: How Broken is Broken?, in Proceedings The Third AusIMM International Geometallurgy Conference (GeoMet) 2016, pp 65–76 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 15, 2016

By Ricky Chipka, Roshan Thapa, Richard Yovichin, Greg Rogoff, Patrick Niemuth

A 4.5-mile-long, 96-inch-diameter outfall pipeline was constructed between North Texas Municipal Water District’s proposed Sister Grove Regional Water Resource Recovery Facility and the Stiff Creek Discharge Structure. Two TBM-mined tunnel segments were excavated for the outfall pipeline through rock and mixed-face conditions within the Austin Chalk Formation. The TBM mining performance was tracked in detail and evaluated during mining. This paper discusses the TBM configuration, TBM utilization, advance rates, and challenges of both tunnel segments.

Jun 13, 2023

By J. D. Price, W. M. Bertholf

One of the chief difficulties with which the operator of a coal washing plant has been forced to contend is the handling of the very fine coal. First he has the problem of separating the fine coal from washery water. This is usually accomplished by the use of settling cones or Dorr thickeners: in either event the separated fine coal contains a high amount (40 to 80 pct) of water and, somewhat loosely, dependent upon the size of the coal particles present, may be known as sludge or slurry. His second problem is the satisfactory further dewatering of such separated sludge and/or slurry.

Jan 1, 1949

By S Harvey

An inrush of water or mud into an underground mine, or sudden subsidence above mining voids represent low probability but high impact risks in underground mining. About two such incidents involving multiple fatalities or loss of production are reported each year worldwide. On average, Australia experiences one such incident every three to four years. This paper reports the development of a Standard that is intended to eliminate fatalities due to inrushes and subsidence.

Jan 1, 1998

By Bo Hyun Kim, Mark K. Larson

This study was developed as part of an effort by the National Institute for Occupational Safety and Health (NIOSH) to better understand rock-mass behavior in longwall coal mines in highly stressed, bump-prone ground. The floor-heave and nofloor- heave phenomena at a western US coal mine could not be properly simulated in numerical models using conventional shear-dominant failure criteria (i.e., Mohr–Coulomb or Hoek–Brown failure criterion). The previous numerical study demonstrated these phenomena using a user-defined model of the s-shaped brittle failure criterion in conjunction with a spalling process in the FLAC3D numerical modeling software. The results of the FLAC3D modeling agreed with the observations of the relative amounts of heave from each gate-road system. However, the FLAC3D model adopted many assumptions and simplifications that were not very realistic from a physical or mechanical perspective. To overcome the limitations of the FLAC3D model, 3DEC modeling in conjunction with the discrete fracture network (DFN) technique was performed to better understand the true behavior of floor heave associated with underground mining in an anisotropic stress field. The effect of stress rotation in the mining-induced stress field was considered by using a different geometry of rock fractures in the coal seam. The heterogeneity of the engineering properties (i.e., cohesion and tensile strength) were also considered by using Monte Carlo simulations. Consequently, the 3DEC models using the DFN technique resulted in predictions of floor heave that agreed with observations of the relative amounts of heave from each gate-road system, but the cause of heave was mainly related to the degree of anisotropy instead of the size of the pillar.

Apr 14, 2022