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By Alexander N. Winchell

The cities of St. Paul and Minneapolis are located side by side on a double loop in the Mississippi River near the eastern boundary of Minnesota. Both cities lie on both sides 'of the Mississippi River, which in this region describes an S-shaped curve. The two cities together have a population of over 600,000 people, gathered in an area which has grown to be a single urban district inasmuch as the two cities have expanded until they occupy all the territory formerly between them, though the business centers are ten miles apart. St. Paul is located at the head of navigation on the Mississippi River and Minneapolis, farther upstream, at the Falls of St. Anthony. A recent water¬power development below the Falls of St. Anthony, constructed by the Federal Government, has at the same time made possible navigation to the foot of St. Anthony Falls through a lock around the dam which replaces the former rapids. Minneapolis, in 1920, had a population of 380,000 people, and St. Paul, 235,000. The two cities occupy land at an elevation of 700 to 900 feet above sea level. The average elevation is slightly less at St. Paul. Minneapolis has nearly 4,000 acres of parks and park¬ways, while St. Paul has nearly 2,000.

Jan 1, 1920

By P. Christmann

The operational paradigm of mining industries is shifting from ?optimal profit for the financial stakeholders? to a new concept compatible with sustainable development ethics: ?maximize economic and social returns at the local, national and global levels, while avoiding negative environmental impacts?. The number of stakeholders concerned by mining companies has grown significantly over the last few decades, and the role of local communities and civil society is now acknowledged by the mining companies adhering to the sustainable development ethics. ?Involve me? is becoming a key to maximize the returns the mining industry can provide to sustainable development. As the world?s major importer of many mineral commodities, several coming from developing countries facing severe short-term problems, the European Union (EU) is an important stakeholder and has a responsibility in supporting actions to strengthen corporate and public governance capacities. The purpose of this paper is to highlight the drivers leading to the development of sustainability indicators and to propose, within the 6th European Framework Programme for Research, Technological Development and Demonstration Activities (FP6), an European-level initiative to develop sustainability indicators adapted to the mining industry and its population with relevant data.

Jan 1, 2003

By Z. Konstantinovic, M. Ahrens

Due to the large installed electrical power and the large number of electric drives in minerals and mining plants power factor compensation and harmonic filtering has always been an important issue. For the design of harmonic filter and power factor compensation installations several approaches can be taken. The paper describes different concepts and their advantages and analyzes special requirements and design considerations for minerals and mining plants. It also highlights areas where problems can occur and which points need to be addressed carefully. Optimized designs and solutions are discussed in case studies and the resulting energy savings and benefits for the plant operation are shown.

Jan 1, 2007

By M. T. Ityokumbul

The liquid phase mixing in Western Research Centre (WRC) pilot plant flotation column with diameter of 0.76 m has been characterized using a salt tracer. The process variables studied were gas and liquid flow rates. The response of the column to a tracer pulse input was monitored at three axial and two radial locations. For all the experimental conditions investigated in the present study, radial and axial concentration gradients were not observed. It is thus concluded that the 2 tph flotation column is behaving as a well mixed tank. This finding is consistent with the observed poor recoveries of coarse fractions in the column flotation circuit. Based on the findings of this report, it is recommended that several schemes of reducing the backmixing be implemented and evaluated for their effectiveness in improving the column recoveries.

Jan 1, 1994

By Nate Ober, Heath Rushing

"Mining companies want to be in a position to move quickly and seize a favorable market or to keep their key staff productively busy. One of the problems for these companies is the time required to compensate for unavoidable impacts that the mine will have on the natural environment and to gain environmental permits. All too often, circumstances that were favorable when the project was proposed have become less favorable by the time all the hurdles have been cleared.Accordingly, many mining companies are interested in ways they can inject more predictability into their timelines for gaining environmental permits, shorten those timelines, and be more certain of getting the permits they need to carry out their next project.One increasingly popular way to do this is through a relatively new kind of service — the mitigation bank.Mitigation banks purchase property or easements through property that has been impacted by agricultural, industrial or resource activity. They then turn it around from an environmental point of view. This might include restoring streams and wetlands so that fish and aquatic organisms can survive, and animals have habitat and food to flourish.Appropriate native species of plants including trees and shrubs are planted, and steps may be taken to introduce wildlife to the new habitat. In some cases, a special focus is placed on creating habitat for rare and endangered species of plants or animals.The property is inspected by regulatory authorities, coordinated through an interagency review team (IRT). If the property is determined to be effective as natural habitat, the mitigation bank is then issued credits that it can then sell to development projects that are creating an unavoidable permitted environmental impact elsewhere. A mining company, for example, would buy credits to offset the aquatic impacts due to construction of a mine, access roads and other infrastructure — as required by the Section 404 Clean Water Act permit that governs those unavoidable aquatic impacts. The mitigation bank used for offset must have an IRT-approved service area that includes the location of the impacts."

Jan 11, 2017

By Robert E. Gray

The vat leaching operation at the Yerington Mine was started in October, 1953. The original plant facilities consisted of primary and secondary crushing, eight leaching vats, precipitation launders, sulfuric acid plant and the necessary maintenance, warehouse and administrative facilities. By 1961, 35,000,000 tons of oxide ore had been removed from the mine exposing the underlying sulfide ore body. A 5,000 ton per day concentrator was constructed and put into operation to treat the sulfide ore in November, 1961. The original crushing plants were used for both oxide and sulfide ores. By adding a third crushing shift for six days per week, the treated ore was increased from 12,000 to 17,000 tons per day. To balance the oxide and sulfide ore reserves, the concentrator was expanded to 13,500 tons per day in 1967. Again, no additional crushing facilities were added. It was anticipated that the treatment rate of oxide ore would be reduced from 12,000 to 9,000 tons per day. Instead, the addition of two crushing shifts per week, and improved operating procedures, increased the treated ore to 26,500 tons per day, 13,000 tons to the vat leaching and 13,500 tons to the concentrator.

Jan 1, 1975

By Richard B. Berg

Chlorite veins in the Silver Star district (40 km southeast of Butte) were of little interest to those who were mining gold and silver in the late 19th century. It wasn't until 1975 that unusually pure magnesian chlorite of the variety clinochlore was identified from a ?talc? claim in this district. In 1977 tests by Cyprus Industrial Minerals showed that this chlorite was suitable for use in ceramics. Mining begun in that year continues. These replacement veins of chlorite in Precambrian quartzofeldspathic gneiss differ from the metalliferous veins to the northwest in both attitude and mineralogy.

Jan 1, 1982

By K. Sasaki, H. Miyakoshi, K. Mashiba

A ventilation analytical system adapting nodal pressure method using skyline modified Choleski's decomposition scheme for network-flow analysis and a new practical system to estimate various thermal air conditions has been developed. The quasi-linear equations for solving steady-state network airflow have been described using the connective function in general forms. The skyline modified decomposition scheme has an advantage on rapid convergence and the sake of computer memory space com- pared with other schemes. The key part of the analysis for climatic conditions through network airways is how to estimate the temperature of the airway rock-surface with partly or full wet condition. A practical and simple solution without any iterative calculations for its estimation has been proposed. This new solution is applicable to practical ranges of airflow temperature, humidity, rock thermal properties and wetness. The present analytical sys- tem have been successfully applied to a ventilation simulator named "M1VENA"developed by authors.

Jan 1, 1996

By R. R. Young

Prior to 1903, the world's supply of sulphur was primarily from surface deposits in Sicily. The discovery of the first salt dome sulphur deposit in 1867 and successful development of the Frasch process for recovering the sulphur resulted in a large part of this essential element being supplied from these mines since 1920. Although the basic process is the same today, engineering and technological developments have evolved to allow its application under many adverse conditions. These and other challenges for the industry in today's environment will be discussed in the paper.

Jan 1, 1979

By T. Janke

When Homestake Mining Company's Mclaughlin Gold Project was being evaluated for development, it was apparent that recovery of gold from mined ore would be difficult and relatively expensive. The ore was refractory, averaging less than 50% recovery in conventional direct cyanidation milling tests. Extensive testing narrowed the processing choices to either autoclave or roaster oxidation before cyanidation. Roasting was ruled out due to higher capital and operating costs --the Mclaughlin mill would be the first large-scale application of autoclave oxidation of a refractory gold ore.

Jan 1, 1989

By G. E. Wasson

Consolidation Coal Co. tested the agglomeration of fine coal using a laboratory pellet mill. The principal operating variables examined were feed coal moisture, coal size distribution, and additives to the feed coal. The moisture of the feed coal was found to be critical to both the pellet mill operability and the product strength. Coals, with feed moistures too high to pelletize, could be pelletized if mixed with lime or a water absorbent material. The addition of dry starch binder improved the product strength.

Jan 1, 1991

By R. Kuhns

The western coast of South Africa hosts a significant diamond resource within gravels associated with paleo-shorelines, channels and transgressive lag deposits. Diamonds were transported from the Kaapvaal Craton to the coast largely during the late Cretaceous via the paleo-Orange river systems. On shore and near shore environments are underlain by Proterozoic metamorphic and granitic rocks which provide gully and pot hole-type traps associated with paleo-channels, basins, bays and beaches. Inner and mid-shelf environments are covered by diamondiferous, poorly lithified upper Cretaceous and Tertiary sediments. The upper Cretaceous gravels were reworked along the sediment-starved coast during much of the Tertiary. Reworking was mainly achieved during marine flooding events which produced lag gravels along the paleo-shorelines. This process reworked the diamonds from low-grade Cretaceous gravels and concentrated them in higher-grade Tertiary gravels.

Jan 1, 1995

In this paper, a mixed integer linear programming (MILP) model for the short-term scheduling of open pit mines is formulated. The proposed model aims at sequencing the blocks extraction over multiple short-term periods. The model takes into account multiple processes, waste dumps, and multiple stockpiles. The short-term scheduler makes a decision on the period, destination, and route that ore and waste are supposed to take to minimize costs while meeting all the mining and processing constraints. The destinations of the extracted materials are also controlled by their rock types. A monthly short-term production scheduling case study of an iron ore deposit is carried out over a year to validate the model.

Jan 1, 2011

By E. Tarshizi

Research was conducted to develop a simulation and animation model for an aggregate (sand and gravel) mine operation. This model can assist the mine engineers to investigate and consider the various options of haulage systems which are critical for the mine operation productivity. Discrete-event system simulation studies can be used for the typical haulage issues that mining engineers are often faced with: using truck fleet haulage, conveyor belts, or a combination of both. The simulation has identified some strengths and weaknesses in the current loading and hauling fleet of the mine, and has resulted in some suggestions for improving the system. The simulation includes animation of the operation. Animation is needed to enhance the benefit of any mine simulation model. By combining the visual power of animation with a mine simulation, a complete picture of the mine system is obtained and displayed. The mine is modeled and animated using GPSS/H® and PROOF Professional®, both of which have shown great applicability in discrete mining simulation projects.

Feb 23, 2014

By Syd S. Peng, C. Y. Chen

Introduction The Surface Mining Control and Reclamation Act was passed in 1977 to put an end to the uneven environmental standards and enforcement established by various coal mining states in the US. One year after passage, the Secretary of Interior was directed to promulgate permanent program regulations implementing Title V provisions of the Act. These regulations were to form the basis for state regulatory programs under the Act and to allow states to assume primary regulatory responsibility. To implement the underground mining provision of the Act, the Secretary is directed in section 516(a) of the Act to promulgate rules. But they must take into consideration the differences between surface and underground coal mining. The regulations developed by the Secretary in 1979, with respect to subsidence control, included: • a subsidence control plan as part of the permitting process; • substantive provisions establishing performance standards for subsidence control; and • provisions providing for the prohibition of mining under perennial streams, impoundments larger than 24.6 dam3 (20 acre ft), and certain public facilities and urban areas. Industry challenged the Secretary's regulations implementing the subsidence control provisions. The litigation was consolidated with all other challenges to the permanent program regulations. (Permanent Surface Mining Regulation Litigation, Civil Action No. 79-1144; D. D.C., May 16, 1980.) In two opinions dealing with the multitude of issues raised by both industry and environmental groups, the US District Court of the District of Columbia ruled against industry. It upheld the promulgated subsidence control provisions. The US Court of Appeals stayed the appeals pending the agency's review and revision of its regulations. The regulatory reform was conducted in accordance with the order from the Secretary of Interior and the President in 1981. As a result, the subsidence control regulation was revised, reproposed, and finalized in June 1983 (Federal Register). This regulation, along with others, was again challenged by environmental groups and industry. On Oct. 1, 1984, the court, after finding the Secretary's reading of the Act reasonable, upheld the 1983 subsidence regulation except for one section. On Feb. 21, 1985, in accordance with the court's ruling, the Office of Surface Mining (OSM) suspended a portion of 30 CFR 817.121 (c)(2) concerning the damage correction requirement for structures or facilities and reproposed it on July 8, 1985 (Federal Register). In conjunction with a request for public comments, OSM now also seeks comments on the omission from the 1983 rule of the requirement in the 1979 rule regarding a presubsidence survey and monitoring of damage to structures. Technical issues related to subsidence regulations The subsidence regulations of June 1, 1983, consist mainly of two parts: a subsidence control plan as part of the permitting process; and substantive provisions establishing performance standards. The latter also includes provisions for prohibiting mining under certain areas. Under subsidence control plan section 784.20, minimum require-

Jan 2, 1986

By G. M. Wali Ullah, Micah Nehring, MEHMET KIZIL, PETER KNIGHTS

In operations that use the sublevel stoping mining method, production scheduling takes into account factors — including ore reserve envelopes, ore grade averages, equipment capacity, feed controls to the mill, and geotechnical restrictions — across the scheduling horizon. Mathematical programming is one of the most effective methods for enhancing the decision-making process in regard to the most viable production schedule in light of a given set of limitations. The majority of research on sublevel stope mining focuses primarily on a single objective of optimization, which is to maximize the net present value (NPV). Environmental, social and governance (ESG) considerations are becoming more prevalent in the mining industry. This includes aspects relating to deforestation, land disturbances, gas emissions, community relations and water usage, among many others. Institutional and other kinds of investors are becoming more interested in the work that resource companies do regarding their ESG obligations. This review article identifies the gap in the existing literature and proposes to simultaneously optimize the production schedule around three objectives. Two of these relate directly to ESG aspects

Jul 1, 2024

By Steven J. Schatzel, Kayode M. Ajayi, Marcia M. Harris, Zoheir Khademian

Predicting rockmass permeability is critical in evaluating various engineering designs, including estimating gas inflow to a longwall mine in the case of a hypothetical breach in the gas well. This study conducted field permeability measurements to validate a geomechanical model capable of predicting rockmass permeability during longwall mining. A series of slug permeability tests were conducted in an active mine in Pennsylvania. A model of the mine was constructed in 3DEC numerical modeling software, and permeabilities were calculated. The modeling results agreed well with the pre- and post-mining permeability measurements, showing the applicability of this tool to evaluate gas well stability near mine workings.

Feb 1, 2024

By L. B. Sand

Zeolite ores and protores occur in extensive deposits in the western United States. A recent paper1 describes the general geology and mineralogy of these deposits and their geographical distribution. The zeolites are alkali-and silica-rich varieties of mordenite, erionite, chabazite, phillipsite, ferrierite, and clinoptilolite. The zeolites were formed primarily by the alteration of Tertiary pyroclastics and in some cases by the alteration of Tertiary siliceous flows. The altered pyroclastics are of principal economic significance. The volcanic ash and tuff were deposited in restricted basins where saline lakes developed. The pyroclastic layers often are of uniform thickness and macrotexture for miles from the center of the basin and interfinger with detritals toward the edge of the basin. Thus, in addition to unaltered volcanic glass, the gangue minerals in these deposits include some combination of primary minerals in the pyroclastics, alteration products of the glass other than the zeolite of interest, and detrital minerals. The gangue minerals include quartz, cristobalite, tridymite, opal, orthoclase, micro cline, montmorillonite, hornblende, calcite, gypsum, thenardite, and iron oxides. The presence of one or two other zeolites in the layer in some cases also is considered as gangue. There are no quantitative mineralogical descriptions of these deposits in the literature; this: study was undertaken to obtain this information. As the zeolites occur as single crystals, crystal aggregates, zeolite-glass particles and in cemented aggregates, a method of study was chosen which would give the size distribution of the zeolite in these types of association. For this reason dispersion of the rock was achieved with a minimum of grinding action. This excluded those zeolite ores, silicified by hydrothermal altera¬tion which require grinding. A relative index of the ease of disaggregation of the zeolite ores thus is obtained, but the technique does not give absolute size distributions of the zeolite crystals. Samples were selected for analysis which do not necessarily represent the best ore horizon, but do represent a spectrum of zeolite occurrences from significant deposits. They are mordenite, erionite, and phillipsite from Rome, Oregon, clinoptilolite and chabazite from Reese River, Nevada, chabazite (and var. herschelite) from Bowie, Arizona, erionite from Jersey Valley, Nevada, and erionite from Pine Valley, Navada.

Jan 1, 1967

By James J. Fallon

Last summer Larry Miller of Roberts & Schaefer told me that his AIME committee would like me to present some thoughts on the marketing of industrial mineral fillers and pigments to this illustrious group in Las Vegas. Shortly after, Brian Coupe of "Industrial Minerals" (the magazine) notified me that I would be presenting a paper to the Fourth International Industrial Minerals Congress in Atlanta this June. It seems to me now it might have been more appropriate to reverse the papers. Las Vegas, a town based on risk, might want to hear what we have to say in Atlanta. The subject for June is "Risk Philosophies of U. S. Industrial Minerals Companies". However, upon reflection, marketing of industrial minerals reflects risk philosophies to a considerable extent, so we'll cut the deck and deal on the subject of marketing.

Jan 1, 1980

By W. G. Lacy

Anticipation of problems and the adoption of corrective measures in the design of engineering structures, establishment of pertinent building codes, and urban planning and zoning to obtain optimum land usage and conservation of natural resources demands a thorough understanding of geological conditions of a developing urban area. In the and to semi-arid southwestern United States erosional and depositional processes result in special situations that require special precautions in building practices. A series of studies currently underway in the Tucson area prompted by foundation failures and breaking, of buried service lines serve to illustrate some of these relationships between the geological environment and history, and engineering problems.

Jan 1, 1963