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By Duluth Engineers' Club, Engineers' Club of Northern Minnesota

"The history of Duluth commences with Daniel de Greysolon du Lhut, one of the explorers of the Upper Mississippi who came to the head of the lakes in the summer of 1679. Radisson and Groseillier, and Claude Allouez, a Jesuit priest, are supposed to have visited the head of the lakes, -but there is no authentic record previous to that of du Lhut.In 1792, the fur traders established a fort at Fond du Lac, fifteen miles up the St. Louis River from Lake Superior, but within the limits of the present city •of Duluth. In the early 50's, there were a few scattering settlers at Oneota and around the George Stuntz trading post on Minnesota point. In 1855-6, the settlement on Minnesota point was called Duluth, commemorating the name du Lhut, and organized as a town in 1857. The first board of trustees and town council consisted of -William Nettleton, J. B. Culver; Robert E. Jefferson, Grin W. Rice and William Old: In 1870, the city of Duluth was incorporated, and five years later a portion of the same territory was incorporated as the village of Duluth, and the two municipal corporations were still in existence on March 1, 1887, when the city and the village of Duluth were incorporated as the present city.The first saw mill in Duluth was erected in 1856-57, on the present site of the ship canal. It cut logs from a virgin forest at the upper end of Minnesota point.The first railroad was built to the head of the lakes in 1870. The charter for this road had been granted in 1861 to the Lake Superior and Mississippi Railroad Company, afterward called the St. Paul and Duluth, and which is now a part of the Northern Pacific Railroad."

Jan 1, 1920

By L. Yuan, A. C. Smith

MFIRE, the mine-fire simulation program of the U.S. National Institute for Occupational Safety and Health (NIOSH), is widely accepted as a standard for assessing and predicting the impact of a fire on the mine ventilation system and the spread of fire contaminants in coal and metal/nonmetal mines. MFIRE has been used by U.S. and international companies to simulate fires for planning and response purposes. It is a dynamic, transient-state, mine ventilation network simulation program that performs normal planning calculations. It can also be used to analyze ventilation networks under thermal and mechanical influence, such as changes in ventilation parameters; external influences, such as changes in temperature; and internal influences, such as a fire. The program output can be used to analyze the effects of these influences on the ventilation system. Since its original development by Michigan Technological University for the former U.S. Bureau of Mines in the 1970s, several updates have been released. In 2012, NIOSH completed a major redesign and restructuring of the program with the release of MFIRE 3.0. MFIRE’s outdated Fortran programming language was replaced with an object-oriented C++ language and packaged into a dynamic-link library. However, the MFIRE 3.0 release included no change or improvement to the fire-modeling algorithms inherited from its previous version, MFIRE 2.20. This paper reports on improvements that have been made to the fire-modeling capabilities of MFIRE 3.0 since its release. These improvements include the addition of the t-squared fire as a new fire-source model and the ability to include available heat-release-rate versus time data, the addition of a moving fire source for conveyor-belt fire simulations, improvement of the fire location algorithm, and the identification and prediction of smoke-rollback phenomena. All of the improvements discussed in this paper will be included in MFIRE 3.1 and released by NIOSH in the near future.

Jun 1, 2016

"INTRODUCTION In recent years, there has been increasing focus on environmental and social impacts of the extractive industries, climate change and resource scarcity. The concept of the circular economy aims to replaces the “take-make-dispose” economic model with one that eliminates waste of all kinds and is restorative by design. Such closed-loop systems implicitly aim to reduce the quantity of primary extracted materials entering the economy, thereby affecting supply and demand dynamics, hence mining industry economics. For the metals industry, the ability to engage in, or adapt to the circular economy can be heavily affected by industry structure and geographical factors. Eco-efficiency initiatives that reduce waste and environmental impact may help the mining and metals industry align with some of the goals of the circular economy. This paper focuses on base metals, and explores case studies in copper, lead and zinc. It analyzes primary and secondary metal production, and recycling. It examines company structures and how these affect engagement with the circular economy. CIRCULAR ECONOMY PRINCIPLES Ellen MacArthur Foundation (2012) describes the circular economy as “an industrial system that is restorative or regenerative by intention and design”, which “replaces the ‘end-of-life’ concept with restoration”, and “aims for the elimination of waste through the superior design of materials, products, systems, and, within this, business models”. The concept is systems focused. For materials such as metals, a series of loops are considered, including maintenance of devices, reuse, refurbishment and recycling. Potential methodologies to achieve circular economy outcomes include disassembly and reassembly of manufactured goods, leasing rather than buying major appliances, and converting to renewable energy sources. The circular economy is partially aligned with the principles of eco-efficiency, which relate to reducing the environmental impact per unit of a material produced. PRIMARY AND SECONDARY METAL PRODUCTION Base metals (copper, lead, zinc and nickel) are essential ingredients in modern economies and are key commodities produced by the global mining industry. Metal production can be categorized as primary or secondary. Primary metal comes from the processing, smelting and refining of metal content extracted from ores, while secondary production comes from metals recovered from recycled streams (e.g. recycled lead-acid batteries, copper wire scrap, etc.). Metals are stored in natural, anthropogenic in-use and anthropogenic waste stocks. An example of the stocks, flows and processes associated with global copper extraction and use is shown in Figure 1."

Jan 1, 2018

By G. F. Joklik

Although the mineral shortages of twelve to eighteen months ago have given way to oversupply, their memory lingers on. These problems were man-made: booming demand throughout the industrial world, political and industrial unrest and the oil embargo all contributed. But in the minds of many, the shortages conjured up visions of the depletion of the world's mineral resources, a disaster that could be staved off only by drastic curbs on consumption and therefore, curbs on economic growth. A little historical research shows that fears such as this are not inventions of the 1970's. A hundred years ago, for example, the imminent exhaustion of the world's coal supplies was being predicted in Great Britain. The English economist, John Stuart Mill, who was usually more perceptive, wrote a few years earlier that "it is only in the backward countries of the world that increased production is still an important object". And later there was Franklin Roosevelt who said in 1932, "Our industrial plant is built; the problem just now is whether under existing conditions, it is not overbuilt". His concern, in other words, was not with the discovery and exploitation of new natural resources, but with the administration of known resources and with seeking foreign markets for surplus production. In light of copper prices at the time -- just under 6¢ a pound -- that was understandable. These instances illustrate how, throughout the world's industrial history, concern about surpluses of raw materials has alternated with alarm about the adequacy of supplies and with calls for restricting growth.

Jan 1, 1975

By Zhenqi Cai, Mike Lichte, Kimberly Kennedy

The Ohio River Tunnel is the first of three combined sewer overflow tunnels to be constructed under Allegheny County Sanitary Authority's Clean Water Plan. The project consists of a total of approximately 5.5 miles of 18-ft and 14-ft finished diameter, segmentally lined deep rock tunnels and smaller diameter dewater and flow connector tunnels, as well as 8 deep flow drop and access shafts varying from 25-ft to 70-ft in finished diameter and 130-ft to 170-ft in depth. This paper describes the project components and the primary engineering challenges faced during design, including tunnel alignments and shaft site optimization with tight right-of-way constraints and multiple railroad and highway crossings. Assessment of tunneling methodology as well as tunnel and shaft designs and constructability included overcoming 5-bar hydrostatic pressure, abrasive bedrock, and the selection of the appropriate support of excavation systems in high-permeability alluvial soils adjacent to the Ohio River.

Jun 23, 2024

By D. M. Davidson

The economics of geologic exploration have changed materially in the past decade primarily due to the change in three basic factors, namely, increased wages and salaries, increased cost of materials, and a greater complexity in methods of exploration. Following the general economic pattern over the past ten years, exploration costs, have, in general, increased, although there is one heartening exception. A comparative picture is complicated because of advances in techniques which ensue from the introduction of new methods and devices largely for aerial exploratory work, Some of these methods were either in their infancy or unknown before World War II. Geological exploration may well be considered as a form of applied research. True, it has peculiarities from this standpoint some advantageous, others disadvantageous, Some of the advantages lie in the fact that exploration success does not involve the production of a new product which necessitates advertising expense and marketing problems. In normal times there is a well established market for the fruits of a successful mineral find. The outstanding disadvantage of exploration lies in the enigma of deciding when to quit if the sought fop prize is elusive. In the search for buried treasure, man?s curiosity is apt to color his judgment. Even the so-called detached scientist may fall 'all too readily into the wishful thinking of the old- time prospector who is lured on by the thought that the next pull from the drill hole, or the next round from the face will reveal a bonanza. It involves mature judgment and experience to ascertain the stage in exploration when further work is not justified.

Jan 1, 1958

By David B. Spencer

This paper describes a process for separating non-ferrous metals such as aluminum, copper and zinc, from other residential and industrial waste by means of permanent magnets. Although the separator may be used in the recovery of non-ferrous metals from auto scrap, most of the testing to date has been aimed at recovery of non-ferrous metals from municipal solid waste, especially recovery of aluminum from the heavy fraction of a resource recovery plant. In most resource recovery plants the incoming solid waste material is first shredded and then air classified into a light and a heavy fraction. The light fraction which contains mostly paper, cardboard, etc., can be used either as a fuel for power generation or in the production of new paper products. The heavy fraction which remains consists mostly of glass, ceramics, wood, ferrous metals and non-ferrous metals. The ferrous metals may be removed from the heavy fraction by conventional magnetic separators. After primary shredding, most of the glass and ceramic is fine in size and may be screened away leaving a residue of wood, cardboard, and non-ferrous metals. This residual heavy fraction is the input material for the separator described in the present paper.

Jan 1, 1975

By Yuting Xue, Khaled Mohamed

Rib control is a critical component of underground coal mining operations, and comprehensive rib support design is essential for ensuring the safety of miners. However, there is currently no standardized approach for rib support design in the United States. To tackle this issue, the National Institute for Occupational Safety and Health (NIOSH) has developed a standalone application, Design of Rib Support (DORS), for rib stability assessment and rib support design under development load. The rib support design in DORS starts with the rib support density, which is determined from the unsupported rib factor of safety (RibFOS). The relationship between rib support density and unsupported RibFOS was obtained from the collected field data. The objective of this research is to validate DORS rib support design by analyzing the extent to which the proposed design capability was utilized to support the coal ribs using numerical simulations. A series of numerical models with varying overburden depth and rib height were built and the ribs were supported with the DORS-recommended rib support design. The bolt load was analyzed under different conditions and the results show that bolt load varies with the overburden depth, the location of the bolt and bolt length. The load in the bolt(s) increases with the reduction in unsupported RibFOS. The bolt(s) start to yield when the unsupported RibFOS falls below a threshold value of 0.8 and secondary support is necessary.

Jun 25, 2024

By Lake H. E.

The request to participate on your theme panel was accepted with some reluctance but indeed as an honor. My subject was outlined to cover 'Energy Resources - both nuclear and conventional' as related to your theme 'Minerals - Treasure Trove of the West'. This is indeed quite an order and I hope you will forgive me for concentrating mainly on the nuclear-uranium portion with brief references only to conventional fuels some of which will be covered in detail later in your conference. In regard to Uranium, I am speaking on the fringe of the area containing half the uranium reserves in your country and no doubt to many who are very conversant with knowledge of these resources. Nevertheless since our two countries have been very closely allied in both nuclear developments and uranium supplies I hope an exchange of information may be mutually beneficial. Concentration on the nuclear fuel resources is I hope understandable as nuclear energy is the coming source of power which will augment the rapid demand in the industrialized countries and provides hope for economic power in many of the more underdeveloped countries. The situation regarding conventional fuel resources is more widely known and their expanding future revolves around production cost reductions, research into diversified uses, plus more assurance of imports from countries less effected by international controversies determining export policies.

Jan 1, 1967

By T. Panhorst

Evaluation of through-deck blasthole sample reliability at the Lone Tree gold mine revealed a non-systematic bias in the sampling system. Ore is primarily hosted within the Powerline fault zone. Clay gouge, present in the fault zone and typically enriched in gold content, forms agglomerates during blasthole drilling leading to a segregation error during sampling. Replicated samples split from blasthole cuttings piles show through-deck samples to be either significantly enriched or depleted by 1.5 standard deviations or more from the mean gold content of their respective cuttings pile quality of through-deck samples correlates strongly with quantity of clay present.

Jan 1, 1999

By D. T. Kirkwood

The practice of impounding mine water and liquid fine waste in underground mines is increasing. Often these underground impoundments are created by constructing seals or bulkheads designed to withstand the expected hydraulic pressures. Occasionally seals are built for another purpose, usually to act as explosion-resistant ventilation barriers. Due to factors such as clogged drain pipes or unexpectedly high inflow rates, these explosion-resistant seals sometimes become subjected to hydraulic pressures. The incidence of seal failures due to inadequate design and/or construction is also on the increase. Fortunately, to date, no lives have been lost by water seal failures, but a clearer understanding of the design and construction considerations specific to water seals is vital to keep this from occurring in the future. This paper presents technical considerations for the design and construction of seals which will specifically be required to withstand hydraulic pressures in underground mines.

Jan 1, 1995

By J. A. Barrera-Godinez

Traditional batch flotation tests produce a limited number of data points from which to evaluate the kinetics of the process. In this research, continuous weighing of froth, from a modified circular flotation cell, using a computer/data acquisition system., has been coupled with chemical analyses from intermittent froth sampling. This combination has permitted the experimental data to be smoothed such that the flotation kinetic parameters could be determined with enhanced confidence. To demonstrate the procedure, a galena ore was floated to permit flotation kinetics to be investigated as a function of cell parameters. It was shown that the kinetic data of this lead flotation most closely correlated with the Huber-Panu three parameter model. In addition the results illustrated the effect of froth thickness, froth scraper rate and air flow rate on the cell performance, in terms of mass flow, grade and recovery.

Jan 1, 1990

By W. D. Bachman

A study has been made of wet, autogenous grinding of disseminated copper ores, including testing of a large number of samples from Kennecott Copper Corporation's Chino mine. The efficiency with which the various samples could be ground was found to vary over an extremely wide range, even among samples taken from different locations within the same ore body. These variations in grindability can be qualitatively correlated with the composition of the rock and the fracturing and alteration that had occurred. Because of the large-scale non-homogeneity of disseminated copper ore bodies, extensive and careful testing of autogenous grinding is needed. An accurate correlation of the grinding data from various samples with the geology of the ore body and with mining plans will indicate if variations in grinding mill throughput can be avoided in practice by mixing or blending of mill feed and if, therefore, autogenous grinding can be applied successfully.

Jan 1, 1970

By G. Paul Anderson

Personnel at Utah Copper Division's Bingham Canyon Mine use current computing technology to compile pertinent production statistics and mining plans. Within hours after the day's work has been completed, concise reports summarizing the previous day's production statistics, actual production vs. budget statistics, the location of shovels relevant to the mining plan, the performance of equipment, equipment next scheduled for maintenance, etc. are available at the terminals located throughout the mine. Also, engineering personnel us e computerized systems, directly from their offices, to assist them in the timely development of mining plans. Timely and concise reporting and planning capabilities such as these assist mine personnel in their efforts to review mining progress and equipment performance, and as such they are in a better position to detect adverse trends early and to seek appropriate resources or make changes in plans or practices.

Jan 1, 1977

By G. A. Rosario, G. Peach

Twin 8.5 m diameter, 10 km long headrace tunnels under overburdens of up to 1870 m were excavated for the neelum jhelum hydroelectric project in north-eastern pakistan using two main beam gripper tunnel boring machines (tbms). Rock bursts were encountered and presented a significant danger to personnel and equipment. Micro seismic monitoring was installed to analyze rock burst characteristics and to create a database for future reference. Correlation of rock burst characteristics improved the ability to predict the likelihood, location, severity, and number of rock burst events. This paper presents the analysis of the micro seismic data

Dec 1, 2022

By Rajendra K. Devala, Sukumar Bandopadhyay

In order to be able to design an adequate mine ventilation system it is necessary to understand how pollutant masses disperse into turbulent ventilation air streams. The mixing of gases and dusts with ventilating air, and dispersion of these pollutants in mine airways, are important flow or transfer problems. For the solution of such problems, the finite difference technique is often used. In this paper, numerical approximation schemes for the solution of the mass transfer problem have been developed using several explicit finite difference schemes. Results from these schemes have been compared with the analytical solution for spatial and time increments using the concept of Root Mean Square error. The comparison of various schemes reveals that the explicit finite difference schemes analyzed here give more accurate results at lower velocities, though the results are dependent on the spatial and time steps considered. At higher velocities the schemes tends to oscillate about the analytical solution. INTRODUCTION In mining, most of the mine air pollutants, such as respirable dust, methane, blasting fumes and diesel exhaust, are produced at the mine face and in haulageways. Injection of any of these pollutants in the mine ventilating air causes disturbances of the equilibrium state of the pollutant concentration of the ventilating air. The mixing of these gases and dusts with the ventilating air are typical examples of mass transfer processes. Pollutants are diluted by the stream of ventilating air flow along airways and discharged into the outside atmosphere of the mine through a return shaft. The dispersions of these pollutants in mine airways are important flow or transfer problems. Knowledge about pollutant sources, emission and transport of these pollutants are essential for ventilation planning and design to ensure good engineering control over air quality, quantity, and environmental conditions. Modeling of mass transfer phenomena in mine ventilation is largely based on extensive studies of turbulent dispersion in wind tunnels and the lower atmosphere of the earth. The general approach in the formulation of models lies in the recognition that these mass transfer phenomena can be conceptualized as a flow problem that can be solved by the general application of Taylor's theory (1954) of turbulent flow and diffusion with modification appropriate static and dynamic parameters. If the face zone is initially contaminated by a pollutant over a long section (e.g. instantaneous exposure of large gas accumulation, rapid methane release etc.), the process of decontaminating the mine workings can be regarded as displacement and diffusion of the tailing edge of the cloud of contaminates in the form of a semi-infinite gas body, for which a one-dimensional mass transfer equation is represented by: [at + u • ax = Ex ex2 + f (x,t)(1.1)] In Eq. (1.1), the term [~~] is the rate of growth of the concentration in the differential element, while a [(5xx )] is the net gain of material due to convective transfer. The two terms balance the total loss of material due to turbulent dispersion that is represented by [Ex . 21] and f(x,t), the source term for the pollutant in the roadway. Several cases of mass transfer that occur in mining can be identified and modelled using the conservative volume element method. The governing equation, along with the associated boundary and initial conditions, source terms and their solutions are detailed elsewhere (Bandopadhyay and Ramani, 1988, Devala, 1989). Only one mass transfer situation is presented (Figure 1) here for the present analysis. Mixed Evolution of Pollutant (multiple pulses) Typical examples of these situations are emission of pollutants from multiple diesel vehicles in the face area, and gas emission from standing pillars as well as from broken coal seam during coal cutting with a continuous miner. The mathematical statement of the problem along with the initial and boundary conditions are given below, Governing Equation: [do+u- =E d2c(1.2) ataxx dx2] Initial conditions:

Jan 1, 1993

By Ari Jokilaakso, Junjie Shi, Zhuo Chen, Pekka Taskinen, Xiang Gao

The amount of copper flash smelting slag has increased during the recent years along with an increasing slag-to-metal ratio. During slag tapping, some copper sulfide is mechanically entrained. As a result, it is necessary to recover copper matte from the slag by suitable methods. At present, the most common way is slow, controlled cooling in a transfer ladle. However, research on the detailed effects of slow cooling and the function of slag modification is rare. This paper described experiments that were performed at different cooling rates (0.5, 1.5, 3, and 7 °C/min), with and without additive. A detailed characterization of the copper-rich phase and its particle size was subsequentlymade using SEM-EDSmicrographs and image analysis software.With a decrease in cooling rate, the particle size of the copper-rich matte phase became larger. The addition of gypsum and carbon as a slag modifier affected the size of the copper-rich phase slightly, and its chemical composition was modified compared with the experiments without additive.

Jul 31, 2020

By Robin Dill, Julian Prada, Kathryn Kelly, Brian Hann, Todd Moline

Narragansett Bay Commission’s (NBC) Pawtucket Tunnel Project includes construction of the 11,600-ft long, 30-ft ID, deep rock tunnel. This paper presents insight into the features and benefits of lump-sum, design-build that led NBC to select it as the project delivery method. The use of a design-build contracting process that included proprietary meetings to discuss and obtain feedback on Alternative Technical Concepts as well as to facilitate reaching consensus on modifications to the GBR-B is also described. The discussion includes features and benefits of design-build process that not only addressed NBC’s desired outcomes, but also allowed the Design-Builder to propose several innovative changes to the Base Technical Concepts included in the bid documents, and to develop a GBR-C that was compatible with their proposed means and methods of construction and addressed what they believed to be the more significant subsurface risks on the project.

Jun 13, 2023

By William R. Bush

This paper is a presentation of findings based upon an econometric model of the world zinc industry. The model was developed as a simple but useful aid for long-run forecasting and planning purposes. A structure was developed for both simulating real zinc price effects on production and consumption, and for forecasting long-run annual zinc prices and supply/ demand levels. Moreover, a methodology is provided to incorporate the effects of: (1) historic technological advances in zinc supply, and (2) the development of the competitive plastics industry. Finally, reduced form equations are used to generate ex post forecasts to evaluate the model's performance.

Jan 1, 1979

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