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By M. Tomono

Harima Works is operating as the zinc and lead simultaneous smelter utilizing the imperial Smelting Process. The smelter commenced its operation in 1966 with designed capacities of 3500 t/M of zinc and 1500 t/M of lead. After that, owing to the results of progressive developments and improvements in operating efficiency and equipments, it has doubled its production figure. This report reviews our recent developments carried out from 1983 to 1985. Firstly, the furnace bottom design was modified for the purpose of reducing carbon consumption ratio. As a result, shaft operating condition has been satisfactory and carbon consumption ratio was improved by 2%, in addition, furnace zinc production was increased by about 8%. Secondly, the oxygen enriched operation at sintering machine was tested from July 1984 to June 1985, in order to increase the sinter productivity, and to solve the capacity imbalance between sinter plant and ISF. As the test result, it was found out that sulfur elimination rate was increased by approx 10% with the oxygen enrichment of 500 Nm3/hr.

Jan 1, 1986

By Raymond E. Langen

Uranium exploration in the Powder River Basin of northeastern Wyoming has been intensive since 1966 and in 1968 produced significant discoveries of reduced uranium ore by Humble Oil & Refining Company and others. Substantial reserves have been established in the area. High-grade carnotite ore was discovered in 1951 near Pumpkin Buttes in the central part of the basin (Fig. 1). Other mineralized areas were soon established from Pumpkin Buttes south to Monument Hill and Box Creek. Total production from these shallow oxidized deposits in the lower Eocene Wasatch formation was small. The AEC reports total production of 520,000 tons of ore averaging 0.19% U3O8. The authors are indebted to many people within Humble Oil & Refining Company and Esso Production Research Company for their assistance and guidance. SUMMARY AND CONCLUSIONS The Highland ore deposit, discovered in 1968, is a large uranium occurrence located in the southern part of the Powder River Basin. Uranium mineralization consists of sooty, black uraninite and coffinite coating sand grains and is concentrated along the margins of Tertiary fluvial sandstones. Uranium was transported by oxidizing solutions roving through the buried sandstones and spreading into less permeable channel-edge sandstones to form typical rolls and tabular deposits. Unaltered sandstones are light gray to gray-buff where the sandstones have been oxidized, the colors are various shades of red, yellow, and yellowish brown. An Oligocene tuffaceous source for the uranium is proposed; however, leaching of the arkosic and tuffaceous host sediments may also have provided a source.

Jan 1, 1971

This paper details the development of a functional work index that characterises the relationship between the energy that is imparted by a Roller Press into materials, against the resultant size reduction achieved. Such a Roller Press work index is necessary for this new grinding technology to differentiate it from Bond's grinding work index, and to clear up confusion that arises with such a comparison to Bond. The energy usage in a Roller Press does not follow Bond's "Third Theory of Comminution" but rather Rittinger's theory of new surface creation. The relationships for such a work index have been developed from the viewpoint of an equipment manufacturer with the hope that they will be of assistance to the minerals industry in the design of grinding circuits incorporating Roller Press comminution. The work index contains modification factors that reflects the effect of oversize, fines, moisture. closed-circuit operation and roll surface characteristics on the energy verses size reduction relationship. It has evolved from the results obtained from testing of a wide range of ore and mineral types that include bauxite, coal, kimberlite, limestone, iron and chrome ores, base metal and gold ores. The results show that even for such a diverse range of materials, they all demonstrate similarities of behaviour when comminuted in a Roller Press.

Jan 1, 1997

By Andrew Neale

ERIC GUTIERREZ: With that, we'll go ahead with the final speaker of the day, Andrew Neale. Andrew has a master's of science degree in mineral processing from the University of Alberta. He worked at the Falconbridge in Sudbury area, also at Brenda Mines, and then he became part of the Brenda Process Technology group in British Columbia. He joined Freeport in late 1993 in Indonesia, and was involved in process control and automation. He is now the senior manager of metallurgy in New Orleans. He's responsible for designing Freeport's new 100,000-ton-per-day expansion concentrator, which is currently being commissioned. Please welcome Andrew. ANDREW NEALE: With the ongoing explosion in digital computing power, there seems to be no limit to what can be modeled, simulated, and controlled in the mineral processing plant. However, at each stage of development of a control system, it is necessary to complete a cost-benefit analysis for justifying the move to a higher level of control. Incremental improvements in plant performance, while often significant, must be weighed against the costs of implementation and long-term maintenance. This presentation will provide examples of what the author believes are misplaced or misguided process control efforts and make a case for the KISS principle as applied to process control.

Jan 1, 1998

By Lennart Mukka

This paper describes the experiences from construction of a new ventilation system in LKABs Kiruna Mine in Sweden as well as the choice of the method for air flow regulation with concern of life cycle cost and the description of the foundation design. The evaluation of the performance test will be presented.

Jan 1, 1997

By John M. Karpinski

A method and equipment have been developed Tor measuring the impact strength of grains of brittle materials. It is shown that brittle materials develop a characteristic particle size distribution when fractured by impact. A simple mathematical model has been found to describe this distribution, and one of the parameters of the model has been designated the r value. The r value is directly proportional .to impact energy and, for fixed impact energy, it becomes a useful criterion of grain strength. Data are presented on the variation of the r value as a function of sample history, initial size, energy input and number of impacts, The results are interpreted in terms of the flaw theory of brittle fracture.

Jan 1, 1964

By Stephen LaBrooy, David Muir

Gold ores in the geologically more recent rocks are often associated with copper minerals which pose problems of high reagent consumption with conventional cyanidation practice. Many examples exist in northern Australia, Indonesia, Papua­New Guinea, Chile, and Brazil where, despite various treatment options (LaBrooy, 1992), the processing of oxide and transition ores is uneconomic either for copper or gold recovery. Hence, there is a need for a reagent which is selective for gold without leaching copper minerals. The ammonia-cyanide system appears to meet this criterion (Muir et al, 1989; LaBrooy et al, 1991; Costello et al, 1992; Hayes and Corrans, 1992) but it has proven difficult to optimise and apply to a variety of ores due to differences in the mineralogy and reactivity of ores and a lack of understanding of how the system works. Recent work on the mechanism, however, (Muir et al, 1993) has thrown a new light on the problem which should allow better process control. Ammonia­cyanide mixtures behave neither like free cyanide nor free ammonia and too much of either reagent in the mixture is detrimental. The key to the process is understanding how ammonia enhances gold extraction yet inhibits copper extraction in an essentially cyanide environment.

Jan 1, 1993

By Frank Ladwig, Stephen Gos

Tailings and/or wastewater generated from gold extraction plants employing cyanida­ tion must often be treated to remove the cyanides and heavy metals for environmental reasons and/or gold extraction inhibition reasons, due to the presence of heavy metals like copper, which have a detrimen­ tal effect during cyanidation. In recent years, the treatment of effluents contain­ ing cyanides and heavy metals has been widely studied, Among chemical treatment methods, the use of hydrogen peroxide has been universally employed as a viable option. However, in some cases, effluents containing high concentrations of heavy metals and/or solids decompose the hydrogen peroxide, an undesirable side reaction. The addition of stabilizers or other peroxygen compounds together with hydrogen peroxide can, however, considerably reduce the rate of decomposition and thus result in detoxi­ fication costs, which are considerably less than the standard detoxification process using hydrogen peroxide. In some cases, the reaction rate can also be increased, resul­ ting in lower investment costs for new detoxification plants. This paper deals with the results of developmental work performed in the recent past and introduces some new processes with the aim of optimizing reagent consumption and costs.

Jan 1, 1992

By William H. Dresher

A study has been made of the reaction mechanisms occurring during the salt-roast process to form water-soluble sodium vanadate compounds from the vanadium oxide compounds present in vanadium-bearing ores and concentrates. Two reactions have been identified, either of which lead to water-soluble compounds--oxidation of sodium chloride by water vapor and. oxidation of sodium chloride by oxygen. The former reaction has been found to be predominant in the salt-roast process. A kinetic treatment of the data has shown that for the formation of sodium metavanadate the rate-controlling step in the reaction, in which sodium chloride is oxidized by water vapor is the decomposition of a species containing water and sodiumm chloride, on the surface at the gas-solid interface. For the formation of sodium pyrovanadate, the rate-controlling step is the decomposition of a species containing water and sodium metavaradate on the surface. The transportation of water through the system, perhaps as a sodium chloride-water complex or a sodium metavanadate-water complex, and the actual chemical reaction are relatively fast compared to the initial surface decomposition step. A similar treatment on the data for the oxidation, of sodium chloride by oxygen has shown that the rate-controlling step, is the actual transportation of oxygen from the gas-solid interface to the reactive site. This transportation is by a sequence of two diffusion processes. Transportation during the early stages of the reaction is by the diffusion of oxygen through a continuous layer of reaction product. After, the first few minutes of reaction time a second diffusion process begins and is continuous for the remainder of the reaction. This second diffusion process involves the diffusion of oxygen, through a layer of reaction product that has developed voids around which the oxygen must diffuse. The hindering, nature of this latter process causes the rate of transportation of oxygen to the reaction site to be considerably slower than by the simple diffusion mechanism initially followed. A thermodynamic treatment of the data has shown that the energy of activation for the decomposition of the water-sodium chloride species on the surface is -12.1 Kcal. per mole. For the decomposition of the water-sodium metavanadate species on the surface' the energy of activation is -15.1 Kcal. per mole. The results of this study indicate the limiting mechanisms of the basic reactions occurring during the salt-roast process. These results suggest what variables should be examined in applying this information to actual plant operations.

Jan 1, 1961

By Earl A. Berry

Someone once said, "The safest mine is one in which no one goes into." We all recognize this as being perhaps wishful thinking. We also recognize in it a certain amount of truth and an ultimate goal if we are optimistic. All of us are aware of the many things that have been done, are being done and will be done to reduce manpower in mining. For those of us; who are optimistic about this ultimate goal it would appear from the records-we are more than well on our way to the so called safest mine. Let us see what has been done in the past 20 years. T e period from 1935 to 1956. For example in the coal mining industry: In 1935 there were employed 462,903 men who produced an average of 805 tons per man per year or 4.50 tons per man per day. In 1955 there were employed 225,093 men who produced an average of 2,064 tons per man per year or 9.84 tons per man per day. There are no comparable figures compiled for the metal mining industry as a whole that can be broken down in this manner. However, from examination of figures available for different groups in metal mining there is a trend similar to that in coal mining. No-dbout the above figures reflect the intense development and perfection of machines and mining systems to tear out, transport and process our mineral wealth. The figures also show the mining industry has been able to double its production and at the same time reduce its manpower by half. When you compare the number of men employed today with the number which would have been employed 20 years ago to gain todays production at that time it become apparent that greater safety has been accomplished. For example the years 1935 to 1956 for all mining show. In 1935 there were approximately 649,226 men employed in mining and reports show 1,399 fatalities and 74,913 non-fatal injuries. In 1955 when there were 313,883 men employed in mining 496 fatalities and 25,365 non-fatal injuries were reported. To have produced the same tonnage of material in 1935 that was produced in 1955 it would have required the employment of approximately 1,298,452 men. 2,798 could have been fatalities and 149,826 could have had non-fatal injuries. You can now measure the full impact of what has been accomplished in the past 2o years by the aggressiveness of mine management, the wizardry of our engineering personnel and the thoughtfulness and devotion of our safety people and their programs. Therefore, there is a trend towards the goal of our opening statement. We whoare toptimistic believe this trend will accelerate at a-faster pace. Why? Because anyone engaged in the mining industry today can well afford to invest a minimum of $30,000.00 in capital equipment todisplace the labor of one man. This fact alone is a terrific incentive for mine management to apply and manufacturers to develop equipment of a type to get the men out of the mine. Now you can determine this problem not only becomes one of safety but also one of economics, When productivity is stepped up and manpower reduced management is learning the hard way what it means to them; in the profit and los s column when a few minutes of delay or downtime of costly machines and processes occur. They have learned that fast and efficient communication systems are the best means of combating breakdown, delays, bottlenecks, supply problems, the saving of lives and property and increasing production. One large western metal mine was able to increase Its tonnage by 4000 tons a day by using modernup to date electronic type communication system. The National Coal Board of Great Britain recently allocated 45,000,000.00 to study and develop faster and more efficient communications when a survey indicated what a serious bottleneck poor communication in their present systems of mining turned' out Lobe.

Jan 1, 1958

By John Todhunter

Longwall mining is certainly not new in the United States, having first been used in the late 1800's in Illinois, but the surging acceptance of the method is relatively new. The number of longwall installations in this country are nearly doubling annually as this method continues to prove itself as a coal producer's delight terms of operating cost, performance and safety. Since 1951, several longwall installations have been tried in Barnes and Tucker Company operations. Although all efforts actually proved that the system itself could be used in prevailing conditions, it was not until 1967 that a unit was put in use that proved competitive with regular mining equipment, both conventional and Continuous.

Jan 1, 1968

By V. Svalbonas

With the occurrences of serious mill structural failures on both ball and primary mills, the mining industry has entered the era of detailed fabrication specifications. Such specifications, however, have been developed as individual entities, often by people not related to the mill design function. Therefore, there has been no effort to relate mill failure or safety to the existence or elimination of specific fabrication flaws; that is, no cause-effect failure relationships have been developed. The omission of this step produces a specification which can be termed uneconomical at best. The present paper attempts to fill this void, by reviewing methods for design consideration of flawed structures, and describing experimental tests used to tie such data to a meaningful quality assurance program in fabrication.

Jan 1, 1985

By Valerio Violo, Antonio Raschillà, Livia Cicinelli

"The Cityringen project foresees the construction of a new circular metro line in and around the city center of Copenhagen. Both drives, the north and the south one, required the TBMs to be equipped in order to cope with contaminated water table and soil. The north drive mined in water contaminated with chlorinated compounds, including chloroform and vinyl chloride, while the south TBMs excavated in a highly benzene contaminated area, becoming the first TBMs to complete such a challenge. Despite the pollution and the stricter operative procedures, the production has been extremely successful with record up to 520 m in one month and 32 m in one day. 1 INTRODUCTION The Cityringen is an extension of the existing metro line. The 15 km long twin tunnels will form a new circular line with 21 new stations (17 + 4 crossovers). When finished it will interchange with the existing metro, rail and bus infrastructure at key locations around town, taking 90% of Copenhagen citizen at less the 600m from a metro station (Figure 1). The Contract has been awarded in April 2011 to the Copenhagen Metro Team (CMT), a joint venture between the Italian companies Salini Impregilo, Tecnimont and Seli SpA. Tunnels are being excavated with 4 Seli-Kawasaki EPB TBMs, two of which manufactured in Denmark by Seli Tunneling Denmark ApS, which is also operating them. At the moment this article is written 50% of the tunnels have been completed and over 40% handed over for the electromechanical works. Seli Tunnelling Denmark is a Danish company constituted in 2012 as a subsidiary of Seli SpA for this project and subsequently acquired by the Salini Impregilo Group in 2015."

Jan 1, 2016

By Joshua Farmer, Mike Gianforte, Tao Jiang, William Gettings

The Two Rivers Water Reclamation Authority (TRWRA) in Monmouth County, New Jersey, is replacing its aging Pleasure Bay Interceptor (PBI) with a new 54-in interceptor in a 3,250-foot long 8 to 10-foot diameter tunnel and a new 50-mgd main pump station (MPS). A comprehensive phased geotechnical investigation was performed, including SPTs, CPTs and geophysics. A channel filled with soft marine sediments was identified. The tunnel is set in stiff to hard marine soil to enable using a less expensive open-face TBM. The thickness of tunnel cover under the channel is optimized through numerical analyses to avoid a deeper pump station yet maintaining tunnel stability with controlling seepage.

Jun 13, 2021

Modern coal cleaning technologies have allowed coal preparation facilities to become quite efficient at removing sulfur compounds, waste rock and low grade coals from run of mine coal. Up to 50% of the raw mined coal stream may end up as refuse, particularly when the coal originates from longwall mining operations, or is high in partings, rock and impurities. The refuse materials vary from coarse materials removed by physical screening to very fine materials removed by floatation and density separation processes. Coal refuse piles are also known by a variety of other names including "waste dumps", "gob piles" and "slate dumps". The potential hazards of improperly reclaimed refuse include contamination of surface and groundwaters by acidic leachates and runoff, erosion and sedimentation into nearby watersheds, spontaneous combustion, disturbance of topsoil borrow areas, and damage from landslides should large slope failures occur. Many of these problems have been particularly acute for abandoned refuse piles, and modern regulations attempt to minimize the environmental impact of coal refuse disposal operations.

Jan 1, 1993

By D. W. Struhsacker

Mineral exploration has evolved into a sophisticated science which uses powerful scientific tools to make mineral discoveries. In addition to their usefulness in performing mineral exploration, these scientific tools can assist the exploration geologist in assessing environmental conditions at exploration sites. During exploration, environmental data acquisition should focus on data collection efforts which can be easily integrated into exploration activities, and should provide information needed for pre-feasibility and preliminary engineering design studies. Environmental studies performed during exploration should also include an environmental liabilities audit and a fatal flaw analysis to assess whether there are any unresolvable environmental or regulatory issues affecting the project. Performing extensive environmental baseline studies during exploration and project evaluation is neither necessary nor recommended. This paper describes opportunities to integrate environmental data collection with mineral exploration activities. This paper also examines how political and communication issues can affect the outcome of permitting efforts, and recommends a strategy to improve the industry's ability to respond to political challenges and to communicate with the public. This strategy integrates technical and political issues, and implements programs to convince the public of the mining industry's technological achievements and its commitment to resource stewardship and environmental protection.

Jan 1, 1994

By L. A. Clark

Although vein-, syenite-, and pegmatite-type deposits are known in Saskatchewan, recent intense exploration stems from discovery of several exceptionally high grade uranium and uranium-nickel deposits locallized near the basal unconformity of the 1.3-1.4 b.y. Athabasca Sandstone Formation. Graphitic basement rocks and post-Athabasca faulting or brecciation coincident with the unconformity are important in locallizing uranium deposits which form as tabular, shoe lace-like bodies with grades averaging over two percent and containing up to 50,000 tonnes U308. Some deposits have similar nickel contents. A few published sandstone analyses average 0.8 ppm uranium while basement granitoid and meta-sedimentary rocks vary from 0.5 to 20 ppm. In the proposed genetic model, traces of uranium are leached from these rocks by oxidized formation waters sweeping through the sandstone and along faults. Solutions are reduced and uranium is precipitated as basement graphitic meta-pelites are encountered along brecciated fault zones.

Jan 1, 1979

By C. Richard Tinsley

Investment activity in the Pacific Rim of Fire has seen a phenomenal surge from epithermal gold exploration. Individual countries are attractive because of lower up-front minerals lease costs (United States, Canada), better geological prospects (Chile, Indonesia), or cheaper equities (Australia). Since the October 1987 stock market crash, large companies are shedding minority joint venture interests to focus on core businesses. Some vertical integration is evident in Japanese coal investments in the Pacific Rim. This article does not cover the aluminum industry oligopoly, which is multinational in character. Nor does it cover the many Canada to US minerals investments. It will be interesting to see if the new US-Canadian free trade treaty will reverse that investment flow. Cross-border investments The following examples should dispel any doubts about the significance of cross-border investment in the Pacific Rim. BHP, Australia's largest public company, has invested $US 4.5 billion in the JS for the following transactions 1984 $2 billion Utah Minerals 1984 $500 million Energy Resources 1985 $745 million Monsanto Oil 1987 $400 million 50.7% Hamilton Oil 1989 $378 million Pacific Resources Placer Dome, mainly through 76% owned Placer Pacific, has the following gold mine developments in hand including the date the project began, Placer Dome's ownership, project name, its location, and capital expenditures: • 1985, 53.1 %, Kidston, Queensland, $A 139 million; • 1989, 37.9%, Big Bell, Western Australia, $A135 million; • 1989, 60.6%, Misima, Papua New Guinea, $C252 million; • 1990,45.5%, Granny Smith, Western Australia, $A95 million; • 1991, 50%, La Coipa, Chile, $US276 million; and • 1991, 25.3%, Porgera, Papua New Guinea, $C1.1 billion. Australia's Western Mining Corp. (WMC), through a foray of off-market acquisitions in late 1987, acquired con¬trol of five Canadian gold companies for a $A488-million outlay ($C452 million) as follows:

Jan 1, 1990

By M. F. Dibble

Borehole mining, as a viable concept for recovering deep sedimentary mineral resources, historically has been long on promise but short on results. Application of the technology seems best suited for recovery of Miocene phosphate resources on the East Coast of the US. These deposits are potentially enormous in scope and underlie sections of the coastal plain and the near offshore continental shelf. The landside portion of these deposits is generally too deep to mine using conventional open pit methods. Recovery of these minerals requires development of alternative mining systems. A significant proportion of the offshore resources appear to occur at depths below the practical limits of cutter suction dredges and may even exceed the limits of bucket ladder dredges. In most cases, these deposits are covered by overburden that must he removed and redeposited before the mineral section can be mined. The depth, thickness, composition of overburden and environmental sensitivity of a particular location would greatly impact mining system selection. It is probable that dredging would not be an environmentally acceptable mining method in many of the areas underlain by this phosphate rock. In cases such as these, new processes such as borehole mining must be evolved or the resource will remain undeveloped. A borehole mining test program, using an existing prototype borehole system, successfully extracted Miocene phosphate in northeast Florida in 1984-1985. The top of the main mineral zone was 80 m (261 ft) below the surface. Based on the results of this test program. plus subsequent laboratory testing and engineering studies, a new prototype borehole mining system was designed in 1986. This design incorporated several innovations of offering potentially higher productivity and lower power consumption than was achieved with the previous test unit. Economic restraints at that tine prevented the actual construction and testing of this new design.

Jan 1, 1992

By Y. J. Wang

The definitions of system pressure loss (mine head) and system resistance, which are traditionally associated with single-fan net- works, are applied to multiple-fan ventilation networks. The system characteristics -- relations among air power, pressure loss, air quantity and resistance -- are analyzed by introducing the concept of subsystems. These subsystems are associated with the fans located in a cutset of the network. For a multiple-fan network, the resistances for the subsystems and total system are dependent on the quantity ratios of the subsystems. In general the pressure loss of a subsystem or a total system does not vary as the square of the corresponding air quantity. If the quantity ratios of subsystems are all held constant, then the resistances become constant and the pressure losses are predictable from the quantities employing the "square law." The system resistance has a minimum value under the natural- splitting flow pattern. Being independent of the value of system quantity, the minimum system resistance provides a basis for comparing the different networks.

Jan 1, 1983