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By Jr. Smith

Silver-gold ratios were studied at the Tayoltita epithermal vein deposit using channel sample, channel sample line, stope, ore body and vein sample populations. The ratios are highly variable among individual channel samples (25:1 to greater than 500:1) with both high and low values randomly distributed within ore bodies and veins. Whole vein ratios for the fourteen most important ore producing structures range from 44:1 to 105:1, and show zonal distribution relative to two small granitic stocks, low values closest to the intrusives. The zoned nature of the deposit suggests that the stocks, apophyses of an underlying batholith of Late Eocene age, were the heat engines which powered the hydrothermal system responsible for ore deposition.

Jan 1, 1978

By Charles Morris, Patricia Petty

Charles Morris Minerals engineers have a new opportunity to shape their industry's future. They can help secondary school teachers in their own communities improve their scientific knowledge and thus be better prepared to teach their students. Local sections of AIME and other groups are being asked to sponsor expense-aid scholarships for teachers who complete the summer field course A Total Concept of the Mining Industry. Now in its 18th year, the six-week summer course is presented by the Colorado Mining Association Education Foundation Inc., in cooperation with the Colorado School of Mines Office of Special Programs Continuing Education. The course will be held June 9 through July 18. "In the past, we have been successful in soliciting support for teacher-scholars from many organizations, corporations, and individuals within the industry," said John Robertson, Jr., Foundation chairman. "Now we hope to enlist the help of engineers at the grass roots level in identifying qualified local teachers and giving them what it takes to participate in this continuing education program." Robertson said the course provides secondary school teachers, counselors, and administrators with a working knowledge of the mining and metallurgical industries. It also helps teachers recognize career opportunities for their students. "With the industry facing a challenging new era, we must have teachers who can relate the excitement of this challenge to their students. They will inspire future generations of resource finders, developers, and managers," he said. More than 670 teachers in 27 states, including 45 graduates of the "class of '85" have completed the course and gained six semester hours of graduate credit. The Foundation's Planning and Curriculum Committee meets regularly to develop the course outline and recruit the faculty. Lecturers are selected on their ability to communicate with people not familiar with the industry. Last year, 67 faculty members came at their own time and expense to discuss their specialties, ranging from exploration to marketing. Normally, teachers receive scholarship aid in the form of tuition and fees, and transportation and meals while on field trips. Expense-aid scholarships cover room and board on campus for those beyond the Denver-Metro area, and travel to and from Golden. "We hope to broaden the appeal and the geographical range of the program," Robertson said. Inspiration for the field summer program for teachers came in 1967 from a mining engineer, the late C.L. (Lindy) Barker, a 1931 graduate of the Colorado School of Mines. Barker and a group of concerned individuals convinced the Colorado Mining Association to accept sponsorship of the course in 1968. The Colorado School of Mines and its Office of Special Programs and Continuing Education agreed to be a co-sponsor to give it accreditation and provide physical facilities and coordination. The first course was held in 1969. Operating funds were solicited from industry to pay tuition, course material, the cost of a course coordinator, field trips, and overhead. Through the years, personal contact by an industry representative has been the most effective teacher recruiting tool. Through expense-aid scholarships provided by local sections of professional organizations, such as AIME, as well as CSM alumni and other friends, there will now be a greater incentive for more teachers to get to know the minerals industry and pass that knowledge on in the classroom.

Jan 3, 1986

By R. A. Pyper

Laboratory leaching experiments were conducted to ascertain the effectiveness of acidic solutions of thiourea, CS(NH2)2, for dissolving gold from finely disseminated gold ores. The ore tested was from the Chipmunk orebody of the Northumberland mining district in Nye County, Nevada, USA. Extractions of up to 90 percent were attained from the ore. Extraction was shown to be dependent on thiourea concentration, ferric sulfate oxidant concentration, acid concentration, and leaching time. Optimum conditions were an ambient temperature leach near pH 1.0 utilizing 100-200 kg/t thiourea and 50 kg/t ferric sulfate for 8 to 24 hours.

Jan 1, 1981

By Irving D. Cohen

In order to overcome our reliance upon foreign energy sources for both crude supply and finished products, we must realize the goals proposed by Project Independence. In general this involves expanding production of existing and new oil, gas, and coal resources, utilizing and improving nuclear technology and the developing of new energy sources such as solar, geothermal, oil shale, tidal, wind and stimulation techniques. There is a continuing debate, both in the scientific community and the consuming public as to the potentiality of nuclear power generation being cost effective and environmentally and safety conscious. The development of new sources of energy does not occur overnight; it is rather a continuing effort in time and money to achieve the goal of providing energy to an ever increasing demand. The public has been accustomed to the availability of energy whenever and wherever it was needed. The era of "energy gluttony" has begun to fade into the realm of "energy awareness". Unfortunately, it required the action of another country to bring the picture that has been discussed many times in the past by energy suppliers into correct focus. Nevertheless, the public responded by conservation efforts to reduce energy wastefulness. Still, the demand for foreign importation of energy supplies is on the rise. What is our recourse? The largest known unexploited energy resource available in the United States is our coal resources. Moreover, the Department of the Interior has noted that 63 counties in Montana, Wyoming, and the Dakotas hold 60% of the nation's least expensive strip minable coal. This western coal is the most abundant and least costly Fossil Fuel in the United States. It is acknowledged that western coal is an important input in meeting the energy needs of our nation.

Jan 1, 1976

By C. R. DeGennaro, M. R. Girman, J. Bickson, J. P. Homer, C. C. Jobes

Between 2005 and 2021, a NIOSH internal review showed that haul trucks were involved in 54 incidents at surface mines in the United States. Haul truck collision warning and avoidance systems (CXS) can assist in preventing accidents at surface mines. CXS use technologies to detect people or objects and alarm to alert haul truck operators. Robust testing can help ensure that they detect objects without excessive false positive alarms. Testing and validation would increase confidence in and encourage implementation of a CXS. Researchers from the National Institute for Occupational Safety and Health (NIOSH) reviewed documents related to the evaluation and validation of CXS with two objectives: (1) to identify methods and parameters used to evaluate detection performance and (2) to identify gaps in CXS test methods and in detection performance. Stakeholders can use the findings from this research to guide implementation of CXS to improve safety at surface mines.

Mar 2, 2022

Outokumpu Technology’s HSC Chemistry process calculation software enables the user to simulate an entire chemical or physical process. The HSC Chemistry 6.0 contains 21 calculation modules and 11 databases for reaction, equilibrium, heat balance, heat transfer, petrological and simulation applications. Most of the calculation modules automatically utilize the same extensive thermochemical database which contains enthalpy (H), entropy (S) and heat capacity (C) data. This database has been expanded to include more than 20,000 species.

Jan 1, 2007

By James J. Brady, James S. Lewis, Robert B. Gordon, Jimmy W. Honeycutt

INTRODUCTION Tunnel construction has always been an extremely high risk form of contracting primarily due to the inaccessability of information concerning the ground conditions to be encountered during excavation. We certainly make every effort to overcome this problem through borings, geological research, site visits, etc.; but at best owners, engineers and contractors alike are only able to interpolate a relatively small amount of factual data from isolated sections of the project into a forecast of ground conditions for the entire project. In essence this becomes an "educated guessing game" with risk to reward ratios (and subsequently the bid price) in direct relationship to the contractor's confidence in the quality of the guess. In many instances it is economically or physically infeasible to obtain information and of course the total picture is never known until the project is complete. This problem effects the contract format as well as price. The contractor's ability to handle unforseen problems on the project become extremely important as to the project's overall success. The following pages contain an actual case history of a project which affords an excellent example of the entire spectrum of situations resulting from tunnel construction in difficult ground conditions.

Jan 1, 1983

By Dean R. Gehring

Creating projects to reach a goal is not new to American industry. In fact, all major construction projects, from skyscrapers to bridges, are completed using similar project management techniques. However, modern project management is relatively new. It was not formalized until 1962, when NASA and the US Department of Defense recognized the need to develop uniform project management procedures throughout the aerospace industry (Moder, Phillips and Davis, 1983). This management method was not introduced to the mining industry until the early 1970s (Britton, 1983). Project management typically follows an organized, four-stage process —definition, planning, implementation and control.

Jan 1, 1996

By Ellen S. Forbus

Reduction bleaching is used to improve the brightness and color of the kaolin pigments sold to the paper and speciality industries. The bleach re¬duces the iron oxide associated with kaolin deposits to a colorless form by the following reaction: Na2S2O42+ 6Fe+3 + 4 H2O -> 2 NaHSO4 + 6Fe+2 + 6H+ (Conley et al., 1964). At present, sodium hydrosulfite is used by the kaolin industry as the reductive bleach. It is often purchased commercially as a liquid solution and added into an acidified slurry. Before the use of commercial sodium hydrosulfite, kaolin plants manufactured zinc hydrosulfite on site by adding zinc dust to sulfurous acid made by passing SO2 gas into water. This process was abandoned in the 1970s due to environmental concerns about zinc in waste waters. In the 1970s, Engelhard patented a process that made sodium hydrosulfate from an iron hydrosulfate (Tiethof, 1978). Difficulties with separating the iron hydroxide byproduct from the bleach and a decrease in the cost of commercial bleach caused the project to be abandoned.

Jan 1, 1993

By M. R. Grundy

The Robinson project is based on the porphyry copper and gold deposits in the Robinson Mining District, near Ely in Eastern Nevada. The district was mined from the late nineteenth century to 1978 by Kennecott Copper Corporation and its predecessors. Operations ceased when falling copper prices in the late 1970's made their outdated mill and smelter complex at McGill uneconomical. In October 1991, Magma Copper Company (Magma) acquired the many claims that cover the known porphyry copper deposits in the district These occupy a disturbed area about nine miles long and three miles wide between the towns of Ely and Ruth. Magma proposes to build a copper / gold mine and concentrator and expand the existing gold leaching facilities. Several pits, previously mined by Kennecott Copper Corporation, will be enlarged; the use of larger, more modem equipment will result in higher productivity and lower operating costs in general. ICF Kaiser Engineers, of Oakland, California, were awarded the con-tract for detailed design of the process facilities, which was essentially complete by the end of 1993. The project at present is awaiting completion of the environmental permitting process; state air and water permits are in hand, and the Bureau of Land Management's (BLM) current schedule indicates that the final obstacles to construction will be cleared by early fall of this year.

Jan 1, 1994

By Pierre Longtin

"Replacing the aging roadway access to the iconic Golden Gate Bridge, thereby ensuring traffic safety and robustness in case of seismic occurrences, provided an opportunity for major design improvements as well as the development of a parkway that would include the construction of four new tunnels. With an eye to the future, the Doyle Drive replacement project aimed to meet the highest standards for environmental stewardship beyond regulatory requirements. Understanding that lighting equipment is the tunnel‘s subsystem that uses the most energy, the operator was looking for a sustainable solution to light the tunnels. An Intelligent Lighting Control System (ILCS), designed specifically for road tunnels, was acquired to individually control the almost 2000 luminaires lighting the four tunnels. This paper will show the results in terms of energy and operational savings generated over the nine months of operation between the commissioning and the conference in April 2016. INTRODUCTION Electrical & mechanical (E&M) equipment represents an average of 10 % of a tunnel total construction cost. Once the civil infrastructure completed, E&M equipment drives the main part of the expense during a tunnel useful life. Table 1 below describes the impact of various types of energy consumption and their cost impact in tunnels of less than 500 m. It is clear that lighting is the sub-system that requires the most energy. A good lighting strategy is the key to reducing energy consumption due to lighting and a viable solution that will bring important savings in tunnel operations.With a price of $0.14/kWh in California and a planned increase between 3% and 6% per year during the period 2013-2040, the tunnel operators could not afford to overlit the tunnels—particularly when they have to operate it for the next 30 years. However, they also need to maintain the right lighting level to ensure driver safety all the time. The Presidio Parkway project includes the Battery tunnels, which are 240 m (790 feet) and 230 m (750 feet) in length, and the Main Post tunnels, which are 280 m (920 feet) and 315 m (1030 feet) in length."

Jan 1, 2016

By G. M. Wenberg

Bacterial leaching of copper and uranium is practiced in environments containing available sulfur and iron and having a strong acidic reaction. However, many mineral deposits do not have these conditions; the chalcocite and native copper ores in Michigan's Upper Peninsula are examples. Bacterial and fungal populations were observed in samples taken from the White Pine Copper Company tailing pond and mine, and isolates were prepared of the dominant species. The isolates were then screened for solubilization of copper from tailing, ore, and concentrate during incuba¬tion in a carbon and nitrogen supplying medium. Certain Penicillium fungi solubilized significant amounts of copper under neutral to slightly acidic conditions. Leaching apparently was accomplished by release into the medium of metabolites which chelated with the copper.- The process was found to be highly dependent upon the medium and the concentration of copper in the source material. The paper describes sampling and screening techniques, presents the results of experimentation to standardize procedures and maximize the yield of copper, and discusses the nature of the leaching process. This preliminary research reveals a biological process which may find use in mineral extractions but whether it can be applied economically remains to be determined.

Jan 1, 1969

By G. A. Johnson

Basic management principles will be discussed (as they apply to minerals education efforts), especially in light of the changing nature of volunteerism in today’s society. Also, the “minerals education tree” will be presented, along with public opinion / public policy realities.

Jan 1, 2001

By K. L. Lamb

At the Sierrita mine, 40 km (25 miles) south of Tucson, Arizona, Duval Corporation is rapidly gaining operating experience with its new Portable Crushing and Conveying System, (PCCS). As of November 23, 1983, over 4.5 million tons (5.0 million st) of ore have passed through the system. Mining cost per ton for the months of July, August and September was 83% below the average for the first five months of 1983. Although all the cost reductions experienced cannot be attributed to the Portable Crusher, it was a major contributing factor. The Sierrita ore deposit has several natural topographic and geologic conditions which are not favorable to mining. It is not a sidehill deposit and therefore no low-level exit points exist to facilitate truck haulage. The ore is very hard. Quartz diorite, hardest of the three major rock types, averages 172-207 MPa (25-30 000 psi) unconfined compressive strength and may run as high as 345 MPa (50 000 psi). Blasting in this rock produces oversize material which runs approximately 20% 51 centimeters (20 inches). The ore is low grade, averaging slightly better than .30% contained copper and .035% contained molybdenum, with small amounts of silver. These conditions, plus high design production tonnages, make the Portable Crushing and Conveying System (PCCS) practical for Sierrita. Without crushing and conveying, truck haulage would be prohibitively expensive. A typical, October, 1983, ore haul from the bottom of the pit would involve a vertical lift of 260 meters (850 ft) and a horizontal distance of 3 860 meters (12 200 ft) were not in-pit crushing and conveying available. The corresponding cycle time would be nearly 32 minutes.

Jan 1, 1984

By B. V. Cooper

The word "research" has been used in the title of my presentation somewhat against my better judgement. There are many definitions of the word. But the one I like best comes from Webster's New World Dictionary. It reads: "Careful, systematic, patient study and investigation in some field of knowledge, undertaken to discover or establish facts or principles. ..." I like that. In only 9 words, the definition conveys to me the very essence of what should be going on either in or for the coal industry. Unfortunately, not enough coal-related research is going on. And much of what is being done is, in my view, not really as effective as it might be.

Jan 1, 1983

By H. P. van Ormer

The objective of this paper and the developed personal computer program is not to identify or try to identify the actual total drilling cost in any Rotary Drilled Blast Bole Program. The ideas put forth here and in the computer program developed are a very accurate way to measure what is often very hard to identify and interpret -The actual direct operating cost of various drilling package combinations including comparing with available blast hole sizes and patterns

Jan 1, 1988

By J. C. Haptonstall

Stoping methods at the Homestake Gold Mine through 1978 had been traditional overhand cut-and-fill, shrinkage or square set. High costs, low-productivity and safety concerns prompted the mine to search for and adopt a "bulk mining" technique as a primary stoping method. Blasthole stoping had been successful but it is very development intensive, and was not suitable for the mine's accelerated mining program. Vertical Crater Retreat stoping was selected, and today accounts for over 50% of ore production. Case histories representing both the successes and failures of VCR stoping in the mine are discussed.

Jan 1, 1986

By Mark E. Smith

To allow recovery of gold values from ore which cannot be economically processed by the mill, Pinson Mining Company has developed a run-of-mine heap leaching facility. In order to estimate production scale recovery rates, reagent consumption and percolation problems, a series of pilot scale tests were performed. These tests typically consisted of 3,630 metric tons (mt) (4,000 tons) leach ore at a grade of .94 to 1.56 grams per metric ton (g/mt) (.03 to .05 oz.) Au/Ton. Test heaps were loader stacked to approximately 4.3 meters (14 feet) high. Information from these pilot scale tests was employed in the design and construction of the production scale facility. Parameters such as spray rate, leach cycle, sprinkler placement, and barren solution chemistry were determined by the pilot tests.

Jan 1, 1983

By E. A. Rychkun

Mining and environmental objectives have traditionally been in conflict. This conflict reflects a delicate balance between the need to spend money to protect the environment, and the need to save money by extracting minerals efficiently. In an increasing number of cases, profit margins diminish rapidly with new environmental regulations and reactionary measures. Forced cleanups and increasing restrictions are unwelcome expensive processes. A practical solution lies in planning rather than reacting. This requires the ability to precisely quantify and qualify environmentally sensitive problems by providing effective engineering tools to model, visualize and analyze subsurface conditions. Prevention of environmental conflicts, and effective cost control are both rooted in the mining company's ability to construct accurate models, monitor changes, assess contamination risks and to design effective remediation plan. This paper presents a case study where these issues are addresses through the application of a new and innovative technology.

Jan 1, 1993

By S. Hamilton

Borates are essential to life, and to many products that are essential to an acceptable standard of living. They occur naturally in seawater at an average concentration of five milligrams of boron per liter. Fresh water lakes, rivers, streams and ground water generally have concentrations of about one milligram boron per liter. Borates are also present in soil at concentrations ranging from 0.1 to three milligrams of boron per kilogram. Because most of that boron is locked into insoluble minerals, clay or organic matter, boron deficiency is more widespread than boron enrichment. Borates evaporate into the atmosphere from seawater, rain, snow and hot springs. In rain and snow, natural boron concentrations range from 0.002 and 0.1 milligrams boron per liter. All told, boron moves through the atmosphere at a rate of 5 Mt to 7 Mt/a (5.5 million to 7.7 million stpy).

Jan 1, 2005