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By K. N. Han, M. C. Fuerstenau

Challenges in five major areas of hydrometallurgy are presented and discussed. These are: leaching low-grade oxide and sulfide ores; oxidative leaching of sulfide concentrates; processing refractory ores; bacterial leaching and processing: and secondary metal recovery.

Jan 1, 1989

By Mary Fu, Helen Leung, Colin R. Phillips

In uranium mines, the median size of the aerosol has been found to be about 0.1 micron or less. Such small aerosols are readily deposited or "plated-out" on dosimeter interior surfaces resulting in the recording of a low dose. The "plate-out" properties of the CEA alpha dosimeter head are described with respect to aerosol properties in controlled experiments in the laboratory. A simple model is derived to estimate the amount of "plate-out" in the CEA head.

Jan 1, 1981

By David L. Gefvert

A general review of the role of cationic flotation reagents in the beneficiation of phosphate, iron, and potash ores. The three major types of cationic collectors-amines, ether amines, and condensates will be compared and contrasted. The effect of particle size, water chemistry, and water temperature on the choice of cationic flotation reagents for each industry will be discussed.

Jan 1, 1986

By M. Churchill, V. R. Degner

Over the past two decades, declining ore body grades and increased operating and construction costs have provided an incentive for the development of progressively larger flotation machines. As a result, the 1.7-2.8 m3 (60-100 cu ft) flotation machine of the 1950's and 1960's is being rapidly replaced by large volume machines. The result has been improved flotation machine specific capacity (tph processed per sq ft of floor space); specific power (hp per tph processed); and process control simplicity. The recent development and satisfactory plant evaluation of the 28 m3 (1000 cu ft) flotation machine allows economic and operating advantages in high tonnage mill applications. Some principles of mechanically induced air flotation and the development of the large 28.3 m3 (1000 cu ft) flotation machine are reviewed here. Performance evaluation in beneficiating metalliferous ores-copper, zinc, and iron-is also given and recently completed plant results provided. Mining lower grade ore bodies results in the need to process increased tonnage in the concentrator. This greater tonnage requires more individual flotation machines, unless individual machine capacity, or cell volume, is increased. As the ore processing rate of the concentrator increases, the benefits of progressively larger individual cells in the flotation section become more significant. The accompanying figure illustrates the advantages of a larger flotation machine. In the figure, the number of machines in the rougher-scavenger section is related to the plant tonnage for three sizes of flotation machine: 8.5 m3 (300 cu ft), 14.2 m3 (500 cu ft), 28.3 m3 (1000 cu ft). The 28.3 m3 (1000 cu ft) flotation machine results in 95 fewer machines, compared to the 8.5 m3 (300 cu ft) machine at 45.4 kt/d (50,000 stpd) feed. The flotation cell reduction is, of course, doubled at a plant production rate of 90.7 kt/d (100,000 stpd). Using fewer flotation machines saves floor space. The 14.2 m3 (500 cu ft) and the 28.3 m3 (1000 cu ft) machines result in a floor area reduction, relative to the 8.5 (300 cu ft) machine requirements, of 134.7 and 418.1 m2 (1450 and 4500 sq ft), respectively, for the 45.4 kt/d (50,000 stpd) rate and 269.4 and 836.1 m2 (2900 and 9000 sq ft), respectively, for the 90.7 kt/d (100,000 stpd) rate. In addition, flotation practice has shown that the "specific power intensity"-power per unit cell volume-is less for increased cell size. This results in a power draw reduction, for the rougher-scavenger circuit, of between 552 and 686 kW (740 and 920 hp) for the 14.2 and 28.3 m3 (500 and 1000 cu ft) machines, respectively, when processing 90.7 kt/d (100,000 stpd). Fewer cells improve machine control and simplify maintenance needs while reducing floor space and power requirements. These are tangible incentives for the development of large flotation machines for high tonnage applications. Flotation Principles The accompanying figure shows how key hydrodynamic regions influence the performance of a mechanically induced air flotation machine. Air is induced into the fluid from the top of the cell, due to the mechanical action of a rotating impeller. The impeller circulates the liquid, or pulp, from the bottom of the cell. The result of these dual flow paths is the mixing of the two fluids and one solid phase in the highly agitated region where physical contact between the air bubbles, and the solid particles to be floated, is accomplished. The particle to be floated is assumed to have a properly prepared hydrophobic surface prior to flotation. Upon leaving the three-phase mixing region, the "floatable particle-air bubble matrix" and

Jan 7, 1982

By Andrea Biagi, Elisa Comis, Gianluca Bella, Enrico De Panicis, Guido Barbieri, Matteo Giani

The Sotra Link Project is a major infrastructure project in Norway involving the design, construction, financing and maintenance of several underground and surface structures between Sotra island and the city of Bergen, among them 23 tunnel portals, 12.5 km of tunnels and a 900 m long suspension bridge. This paper describes the benefits in applying a Building Information Modelling (BIM) approach to tunnelling, from Early Design to the Detail Design Phase. The BIM application to the Sotra Link Project resulted in several improvements, such as efficient handling of clashes and inconsistencies, deeper understanding of effective design choices (reduction of errors), more efficient communication between designers, enhanced control of project quantities and costs. The advantages of the BIM approach during the ongoing Construction Phase are also explained.

Jun 23, 2024

By E. Harrison

The Greens Creek Ore Bodies are located approximately 18 miles southwest of Juneau, Alaska in an area on Admiralty Island classified as a non-wilderness national monument. An area-wide stream sediment geochemistry program targeted the deposit in October of 1973. Today, after 37,000 meters of combined surface and underground diamond drilling, three ore zones are known to exist with total reserves approaching 4.1 million tonnes. Lying within moderately folded metasediments of an undetermined age, these orebodies are thought to be of seafloor exhalite orgin and contain unusual and impressive amounts of gold, silver, lead, zinc and copper.

Jan 1, 1986

By Ron Allum, Ed VanDerPas

The application of high speed tunneling in a deep underground copper mine is essential for an ambitious expansion project at Magma Copper Company's San Manuel Mine. At stake is the future of over 1,300 employees at the largest producing full gravity block caving copper mine in the world. A joint venture of Frontier-Kemper Constructor's Inc. and Deilmann Haniel GmbH is helping create that future through the successful application of tunnel boring technology. This paper examines the details required to assemble, deploy and operate a 4.62 m open main beam tunnel boring machine (TBM) in a 1048 m deep operating mine accessible only by shaft.

Jan 1, 1995

By Charles Dumaresq

The management of mine tailings poses a complex range of potential risks, including physical risks, such as the risk of catastrophic failure of a tailings facility and chemical risks such as the risk of long-term leaching of contaminants into the downstream environment. If these risks materialize, they can lead to a wide range of impacts on people and the environment, including human fatalities and severe impacts on downstream ecosystems, and the costs of recovery borne by industry, communities, governments, and society as a whole can be immense. Tailings facility failures in Canada (2014), Brazil (2015 and 2019), South Africa (2022), and in other locations around the world underscore how high the stakes are when mines produce and manage tailings (WISE Uranium Project 2019). Understandably, many people do not trust the mining industry to manage tailings responsibly. As an industry, it is our responsibility to manage tailings in a manner that is responsible and strives to minimize harm associated with tailings management, including effectively managing both the physical and chemical risks associated with tailings. Standards have an important role to play in responsible tailings management by setting expectations for standards of care and providing a means to measure and report on performance. In jurisdictions with strong legal requirements for tailings management, standards play a complementary role, pushing performance improvements in areas that may be difficult or impossible to address in legal requirements. In jurisdictions where legal requirements are lagging, standards may represent the de facto leading practice and may be the primary tool to help ensure responsible tailings management. Implementation of standards can help companies demonstrate that tailings are being responsibly managed and help build trust and credibility. Most importantly though, standards are important tools to help ensure that the risks associated with tailings are reduced, and that remaining risks are effectively managed. However, we must recognize that conformance with standards can have a down-side – the proverbial two-edged sword. Having standards is vital but there is a risk that implementing standards becomes a “box checking” exercise, with ongoing conformance leading to complacency. We must not allow ourselves to fall into the trap of believing that, just because we are complying with applicable standards and laws, we are therefore doing our best, and that “it can’t happen to us.” In addition, if conformance becomes the goal and the standard does not have mechanisms to drive continual improvement, then once the standard is met, there may be no incentive to improve. The point of complying with standards is not to pass the test. The point is to manage tailings responsibly, prevent catastrophic failures, and minimize harm. The point is to do better, because we must do better. To do that, we need to strive not for conformance, but for excellence in tailings management, driven by continual improvement and a quest to do better.

Feb 1, 2025

By Gordon R. Wicker, Willem P. C. Duyvesteyn, Robert E. Doane

A versatile acid leach process has been developed which is applicable to a broad range of oxide nickel ores. Inherent in this process are high recoveries of nickel and cobalt, as well as a relatively low energy consumption. These features extend the range of economic exploitation of laterite deposits to low grade limonites and to garnieritic ores not suitable for pyrometallurgical processing. Particular advantages can be realized in treating orebodies containing both limonite and garnierite and ores containing significant amounts of cobalt.

Jan 1, 1979

By Huo Zuzhao

The main feature of caving methods is to draw ore from the overlying waste rock. Research on the movements of ore and waste plays a very important part in reducing ore loss and dilution and raising the economic benefits. This paper gives the basic theory of computer simulation of ore-draw, exposses the physical significance of mathematical model, puts forword a new formula of similarity characteristic value, brings forth a method of adjusting similarity, introduces the major functions of the simulation program and describes the ore draw control and stope parameter selection through computer simulation.

Jan 1, 1986

By David Jenkins

Grefco Inc. operates two diatomite mines in the western Santa Ynez Mountains. The larger of the two mines, the Palos Colorados Mine, is located approximately seven miles southeast of Lompoc. The Miguelito Mine is located about two miles south of Lompoc on the west side of the Miguelito Canyon. Diatomite from the Palos Colorados and Miguelito mines is trucked to the Grefco plant at Lompoc for processing (Figure 1). HISTORY Grefco, Inc. evolved from the originating Dicalite Company which in 1929 began operations at the Walteria plant in the Palos Verdes Hills south of Los Angeles. In 1942 Dicalite leased the Palos Colorados mine at Lompoc. In 1944 the Dicalite Company was purchased by Great Lakes Carbon Corporation.

Jan 1, 1995

By Daniel C. McLean

Chemistry plays a more important role in milling operations than is generally recognized, particularly in fluid- solid separation processes. Chemical aspects are also very important insofar as plant water quality is concerned, and in the manner in which this water quality effects plant design and operation. Aside from the inherent chemical characteristics of plant water, the mineral preparation industry is becoming increasingly more dependent on the use of mining chemical reagents--relatively new to the coal industry, but items of I standard usage in complex metal recovery plants. These chemicals have many useful properties and can produce significant improvements in operations and metallurgical efficiencies when used properly and intelligently. They can produce poor results and sometimes severe losses when used improperly. Most reagents are relatively expensive on a per pound basis, hence costs can be excessive if they are used wastefully or inefficiently.

Jan 1, 1968

By B. A. Donahue

The results of a survey of 46 West Virginia coal samples, employing the Office of Coal Research-Band coal sewage treatment process, indicated that the Freeport coal and Bakerstown coal from Preston County, Pittsburgh coal from Harrison and Ohio County and the Sewickley coal from Monongalia County offer outstanding potential for water clarification. Oxidation, steam treatment and acid and base washing of coal generally resulted in small positive or negative changes to the water clarification capacities of the coal while the employment of prepared coal fractions resulted in more significant benefits. Of the coals tested, those fractions with high ash, high sulfur and low Btu generally possessed the highest adsorption capacities.

Jan 1, 1968

By Y. J. Wang

This paper describes a procedure for solving the generalized system of n network equations in n unknowns considering the following ventilation variables and parameters: (a) air quantities, (b) pressure losses or gains caused by the control devices (i.e., fans or regulators), (c) resistance factors, (d) natural ventilation pressure, and (e) fan pressures (as a function of air quantities). The air quantities and pressure losses for all branches in the network are grouped into dependent and independent variables. The branches with an independent quantity are contained in a chord set, and the branches with a dependent pressure loss are contained in a chord set. In addition to the problem formulation, the solution procedure, applying the Newton method, is discussed and illustrated with a numerical example.

Jan 1, 1989

Industry and regulatory agencies have requested guidance on safe blasting near transmission pipelines. The US Bureau of Mines (USBM) and Amax Coal Co. studied surface coal mine overburden blasting near four steel and one PVC pipeline of 15 to 51 cm-diam (6-20 in.-diam), monitoring vibration, strain and pressure. Unlike tests of small blasts simulating construction, these were up to 1 t (2200lbs) per delay in 31-cm (12-in.) blastholes. Worst-case comparisons showed that 12.7 cm/sec (5 in./s) blasting vibrations produced strains about one fourth that of pressurization and 10% to 18% of the ultimate tensile strength. No failures occurred from blasting as close as 15 m (50 ft), which produced vibrations over 60 cm/sec (24 in./s).

Jan 1, 1995

By M. Z. Rashad, H. A. El-Sageer

The intersections of numerous joint sets at the surface of tunnels of the Abu-Tartour project in Egypt create blocks of irregular shape and size in the rock mass. Although most of these blocks are unable to move into the free space of the tunnel, a few key blocks are capable of such movement. In addition, as soon as they move, some restrained blocks will be liberated. The aim of this work is to find the removable key blocks of the walls, floor, roof and corners of a portion of the tunnel under jointed surface rocks and then determine the best tunnel direction.

Jan 1, 1993

By W. Pariseau, J. Goris, S. R. Dismuke

Ore at the Magmont mine in southeast Missouri is extracted by the room-and-pillar method on two and sometimes three horizons. In 1991, a plan was formulated to recover high-grade ore in pillars using cable halts to accommodate spans of more than 27 m (90 ft ). A test area was selected and a recovery plan developed. A cooperative rock mechanics study was established by Cominco Metals, the US Bureau of Mines and the University of Utah. When initially opened in 1968, the planned production rate was about 910 kt/a (1 million stpy). Due to declining reserves, the production rate was decreased in November 1992 to 570 kt/a (630.000 stpy). Pillar recovery now accounts for about 40% to 50% of the mined tonnage. This method plays a vital role in allowing Magmont to continue to operate.

Jan 1, 1996

By Y. Topkaya, R. E. Johnson, B. R. Palmer, R. B. Bhappu, Ronald J. Roman

The hydrodynamics of the leaching solution in leach heaps is known to be one of the important variables in the performance of the heap. The solution hydrodynamics are also important in the decommissioning of a heap where the aim is to flush out the residual dissolved metals and the remaining reagents. Chemical engineers have studied the hydrodynamics of "trickle bed" reactors for 40 years in an attempt to relate the performance of trickle bed reactors to flow conditions. Their work is reviewed with emphases on areas of similarity to heap leaching.

Jan 1, 1993

By J. C. Ransdell

A conventional paddle-type mixer and a gravity-flow mixing device were evaluated for conditioning of fine phosphate feed (- 35 + 150 mesh) with fatty acid and fuel oil, and for acid scrubbing prior to cationic flotation. Gravity-flow mixing re- quired less residence time but slightly higher reagent concentrations to achieve recovery levels similar to conventional conditioning. Grade was less sensitive to reagent concentration using the gravity-flow mixer. For acid scrubbing, the gravity-flow mixer proved equally effective. In this paper, the effect of time, pulp density, reagent concentration, and emulsification on conditioning and acid scrubbing efficiency of the two devices is discussed.

Jan 1, 1987

By N. Parra, M. N. Herrera, T. Vargas, C. González, B. Escobar

The bioleaching of mineral sulfide pulps in a bench-scale rotating-drum reactor was studied. The reactor contained horizontal paddles on the inner wall for lifting the mineral pulp. The performance of the reactor was tested by bioleaching a refractory pyritic gold concentrate in the presence of pure Thiobacillus ferrooxidans (ATCC 19859). The concentrate was efficiently bioleached at a 50% pulp density with the drum operating at from 0.5 to 1.0 rpm. Attempts at bioleaching the concentrate at the same pulp density used in a conventional stirred reactor showed severe inhibition of bacterial activity. The results demonstrated that the drum reactor allows the process to operate at much higher pulp densities than conventional stirred-tank reactors. This results in improved bacterial activity because of better attrition control of the mineral particles.

Jan 1, 1999