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By Anthony M. Opyrchal

This Bureau of Mines study assesses the economic significance of the Florida phosphate industry to selected counties in Florida, the State of Florida, and the Nation: it also includes a brief survey of the industry's international impact. Based on forecasts of Florida phosphate production in 1981, and using constant 1977 dollars. estimates are given for 1981 for regional and national output the value of this output, income, and employment created by the phosphate industry in Florida, Federal, Stale, and county tax revenues generated by the State's phosphate industry are also estimated for 1981. The concentrated impact of the phosphate industry on certain areas of Florida and on the State?s regional industries is examined using economic base analysis complimented by an industrial complex approach. The industry's impact at the Stare and national levels is examined through input- output analysis. In addition, an attempt to forecast for 1990 the effects of constraints on phosphate rock mining as a result of economic conditions and other factors is included as an appendix to the report. Also discussed is the phosphate industry's importance to the U.S. balance of trade: U.S. agricultural production. Including forward linkages; the U.S. sulfur industry; and the phosphate industry's importance to the production of fluorine and uranium by- products from fertilizer manufacturing.

Jan 1, 1981

By John Greenhalgh, Benoit De Rivaz

"1.INTRODUCTIONThis paper is based on the Lee Tunnel project, which is part of the Thames Water’s Tideway Project.The client Thames Water has employed a Joint Venture of Morgan Sindall/Vinci Grand Projets and Bachy Soletanche to undertake the design and construction of the project under the management of CH2M Hill at a value in excess of £635 million ($990 million). The 3 main elements of the tunnel project are the permanent lining to the shafts, the precast segmental lining, and the secondary tunnel lining. All 3 are reinforced with different types of Dramix steel wire fibers and each element will be described in this paper. This paper will explain the basic structural design of FRC (Fiber reinforced concrete) based on the post cracking residual strength and will describe all the steps of this project, the testing program realized to support innovative design and the main technical learning point. 2.BASIC CONCEPT OF STRUCTURAL DESIGN OF FRCStructural design of FRC elements is based on the post-cracking residual strength provided by fiberreinforcement. Other cases, like early age crack-control or fire resistance, are considered non-structural use of FRC. For structural use, a minimum mechanical performance of FRC must be guaranteed. Fibers can be used to improve the behavior at SLS (Service Limit State) since they can reduce crack spacing and crack width, thereby improving durability and they can be used to improve the behavior at ULS (Ultimate Limit State) where they can partially or totally substitute conventional reinforcement in most conditions. In the design process, the definition of the performance expected from the material is a key factor and the mix-design of the material has to be optimized for the required structural performance.2.1 Testing Method In order to ascertain the structural requirements requested for the FRC segments, preliminary testing on samples will be required and the effectiveness of the proposed solution will also be assured by the testing of full scale specimens. Structural design of FRC elements is based on the post-cracking residual strength provided by fiber reinforcement. For structural use, a minimum mechanical performance of FRC must be guaranteed. Nominal values of the material properties can be determined by performing a 3-point bending test on a notched beam according to EN14651 (figure 1) or by performing the ASTM C1609 beam test:"

Jan 1, 2016

By Charles L. Harness

The barite industry has made notable progress since the days when barite was used only as an adulterant in white-lead paints and the only method of mining it was with pick and shovel. The following chronological record may serve to show how this heavy white mineral has grown in importance in the national exonomy and at the same time to indicate development of methods for obtaining it. 1845. - Barite first, mined in Fauquier County, Va., for use as an adulterant in white-lead paints. 1850 (approx.). - French settlers 60 miles southwest of St Louis, Mo., discovered barite; called it "'tiff;' meaning white. It was mined and shipped to St. Louis for use in paint.

Jan 1, 1946

By Robert D. Pehlke

"Current continuous casting processes are going through a rapid evolution of advances and new developments. At the same time, intense efforts are being directed to the development of radical new technologies such as continuous casting of thin slabs and strip steel.Traditionally, the casting processes for steel have been anticipated by the development and implementation of processes in the non-ferrous industry. This trend is reviewed and what it may portend for steel is described.IntroductionThe continuous casting of steel has been a widely adopted process in the production of steel. The concepts for this processing go back into the early and mid 1800's; however, commerical development was delayed for a variety of reasons until the mid twentieth century.Beginning in the early 1960's, adoption of continuous casting was initiated and continues at this point in time to be accelerated. In Japan, more than 90% of the steel produced is continuously cast (1). More than 50% of the steel produced in the United States is continuously cast and this fraction continues to rise (2). Numerous examples can be cited of installations costing well over $200,000,000 which have provided a payoff in less than a year and a half. As this process has continued to be applied and its technology to increase, computer control systems have been installed. In particular, in the larger plants producing slabs, sophisticated computer systems involving the integration and networking of mini-computers, micro-computers, and mainframe including back-up systems at all levels are being utilized. Pehlke (3), and Harabuchi and Pehlke (4) have described the structure of these systems."

Jan 1, 1988

By Robert M. Lewis

Chemically, mica is a complex silicate of sodium, potassium and aluminum. There are no important uses of mica where the chemical analysis is important, except that in some uses of ground mica, the content of iron oxide present as an impurity must be kept to a very low limit. Muscovite mica is frequently found containing black and red "stain" as a homogeneous part of the books or sheets. In most cases this stain or impurity is magnetite or hematite. Some mica contains impurities deposited by infiltration. This is commonly a red stain, less often brown or white. The best mica is free from all such impurities, and the greater their content, the less value does the mica have.(1) It is because of these undesirable impurities that a large segment of the fine ground mica industry relies on weathered pegmatites and alaskite ores as a source of raw material. The mica concentrates obtained from these ores are relatively clean and require moderate beneficiation to meet color and density specifications. One need only to observe the stained and decrepitated condition of the mica recovered from mica schist to appreciate the challenge that processing this material presents. Despite these adversities there are several advantages to be gained by mining and processing mica schist ores. The mica content of these ores are considerably higher than the pegmatites and alaskite ores now being mined, often containing in excess of forty percent mica. This-higher grade mica feed should promote a lower mining and milling cost with its resulting competative advantage. With more rigid government

Jan 1, 1969

The Sage Mill Project w approved by Santa Fe Pacific Gold Corporation's Board of Directors in October 1994. The Sage Mill Project included a pressure oxidation plant designed and constructed to process refractory carbonaceous ore using fine grinding/autoclaving technology developed specifically to treat Twin Creeks ore. The project was constructed in two phases. The first phase was put into operation on May 5, 1997, just hours before the transfer of ownership to Newmont Gold Company occurred. The second phase started in October 1997. This paper reviews schedule, costs, scope changes, and methodology used on the project that spanned almost five years from project definition through commercial operation.

Jan 1, 1999

By J. A. M. Cano

An extensive research work was developed by Samarco Mineracao S/A to study the quality characteristics of blast furnace pellets produced with high content of MgO. Comparative blast furnace simulation tests were conducted both in Samarco and foreign laboratories. The objective was to evaluate the behavior of high MgO and normal Samarco pellets in the blast furnace operation. Additives such as dolomitic hydrated lime, dunite and magnesite were used for increasing pellet MgO content. The test results showed that pellets produced with high MgO content are similar in quality to normal Samarco Pellets.

Jan 1, 1991

Numerical models play a significant role in the design of safe underground mining excavations and support systems. Advances in the capabilities of numerical modeling software, together with ever increasing computational speeds, have made it possible to investigate the very nature of the large-scale rock mass and its response to mining excavations. The improved understanding of the rock response obtained from modeling enhances our designs, resulting in greater stability and safety of the mining excavations. To help advance the state of the art in this field, the National Institute for Occupational Safety and Health organized the International Workshop on Numerical Modeling for Underground Mine Excavation Design. The workshop was held in Asheville, NC, on June 28, 2009, in association with the 43rd U.S. Rock Mechanics Symposium. The proceedings include 10 papers from leading rock mechanics and numerical modeling experts in the United States, Canada, Australia, and Germany. The papers address a wide range of issues, including various numerical modeling approaches, rock mass modeling, and applications in coal and metal mines.

Jun 1, 2009

By John W. Taber

The Bohemia mining district is a small but intensely mineralized area in western Oregon . For its size , it has made a substantial although somewhat sporadic production of gold throughout a long period of years . The veins also contain lead, zinc , and copper, but in the past these metals have not been recovered in important amounts . In reviewing the progress of mining activity in the district , an effort has been made to gather under one cover all available information on former operations , including methods of mining , production, and geology pertinent to the ore deposits , problems encountered, and other factual data that may affect future mining in the district . A special effort has been made to assemble as many maps of former workings as possible in order that these may be preserved and readily available to assist in future exploration. The data presented herein are based on brief reconnaissance examinations made during several weeks spent in the field in September 1946. These are supplemented by information obtained from various individuals actively or formerly connected with operations in the district . Only the principal properties and several of the more outstanding prospects were actually examined. Many of the older workings were inaccessible.

Aug 1, 1949

By Jesús Contreras

Since the commencement of its activities in Huelva in 1970, Atlantic Copper has maintained a course of action that has been more demanding than the successive environmental legislations current at different times. As its primary objective it has sought compatibility between the protection of the environment and both its industrial activity and the social and economic development of the area in which its Metallurgical Complex is located. For this reason, since the seventies it has maintained a continuous programme of investments which have allowed it to attain its present environmental situation. As a consequence of the Environmental Policy of Atlantic Copper, in April 1998 it obtained certification for its Integrated System of Environmental Management (SIGMA) according to international standard IS0-14001, and under European Community Regulation 1836/93 (replaced by the 76112001) for the Eco-Management and Eco-Audit System (EMAS). The SIGMA formalises the environmental management practices of Atlantic Copper and engages it to have available a system that can be fully audited. Atlantic Copper was the first European Company in the non-ferrous metallurgical sector to obtain both the UNE-EN-ISO 14001 certification and the EMAS registration. The present paper reviews the actions by Atlantic Copper in environmental matters that have allowed it to achieve its present position. It also describes the coming stages of improvement planned and the modifications to be carried out in the near future, in particular the criteria for the selection of technologies on the basis of the concept of BAT (Best Available Techniques) introduced by the European Union, and always guided by the final objective of converting Atlantic Copper into a reference within the sector, comparable to the best designed and operated installations in the world.

Jan 1, 2003

By F. William Bloecher, William B. Plank

CURRENTLY 12,892 students are enrolled in the mineral engineering schools of the United States and Canada, marking an all-time record high for these schools. It shows a remarkably rapid recovery from the effects of World War II. Enrollment in all the other engineering branches has also increased but not so rapidly as in the mineral engineering branch. Almost all the data in this report are from the eighth questionnaire study of the mineral engineering schools made, as formerly, under the auspices of the Mineral Industry Education Division of the AIME. Every school is represented in the data, for which the authors thank the deans and professors who supplied the information. For this reason, the data of all the studies are comparable, an achievement not always possible in endeavors of this kind. For comparison with the general engineering enrollment situation, data are included from the January 1947 issue of the Journal of Engineering Education.

Jan 1, 1947

By J. Paraszczak

ABSTRACT Diesel-powered loaders are a pillar of modern underground metal mining. As these mines are getting deeper and hotter and the emission regulations stricter, ventilation costs are soaring, affecting production cost. Also, the cost of diesel fuel is expected to rise. These may make the use of diesel engines more problematic. Electric load-haul-dump machines (LHDs) are an interesting alternative. This paper compares features and performance of diesel and electric, cable-powered LHDs. It overviews equipment offerings, and compares, analyzes and discusses technical parameters, operational problems and cost issues. The paper gives some conclusions about electric LHD applicability and performance, indicates possible applications, and suggests further research work.

Jan 1, 2013

By Milton Gomez, Nico Sutmoller

Low-density cellular concrete (LDCC) was first introduced to the market in the early 1900s and since then has made continuous technological advances. There are two primary types of LDCC: permeable and non-permeable. Both types of cellular concrete offer advantages in different types of geotechnical engineering applications. Because of its unique characteristics of low density, high compressive strength, and high fluidity during placement, LDCC offers an effective solution for a wide variety of engineering applications, and in many cases provides a more cost-effective, labor saving alternative to traditional fill materials. This paper will review the history, characteristics, and technological advances of LDCC, highlighting multiple real-world case studies that showcase the high-performance capabilities of both permeable and non-permeable LDCC.

Dec 1, 2022

This summary of State laws or explosives was compiled primarily to ascertain what subjects relating to their control have been acted upon by each State legislature and, in general, how they have been treated. It does not include any legislation passed after 1942, or any proclamations, regulations, or administrative orders. It does not purport or attempt to be authoritative. If any problem arises involving interpretation of the statutes of any particular State, the original source must be consulted for the exact words used by the legislature. This summary, however, will be useful In determining whether relevant statutes exist, and In locating them quickly,-with a minimum of effort. It will be of value also in comparing statutes in one State with similar statutes in other States to determine what construction has been placed upon them by the courts of those jurisdictions or to contrast the varying provisions of many States upon a similar subject. To make these comparisons easier, the statutory provisions for each State have been grouped under several major topics in outline form. Although this sometimes has resulted in disruption of the continuity of individual acts, the increased general clarity and availability of comparable sections have more than justified the procedure followed.

Jan 1, 1943

By Edward Hall Smith

The E1 Indio Mine is located in the Andes mountains about 180 kilometers East of La Serena, capital of the Fourth Region of Chile. It is reached by an international highway running up the Elqui Valley as far as Juntas from where the last 42 kilometers is on a road constructed by the Company. The plant is located at 3.900 meters above sea level among extremely rugged terrain with nearby mountains rising about 5.500 meters. Climatic conditions at these altitudes are severe with winter temperatures down to -20°C. Snow storms lasting several days and leaving up to two meters of snow have been experienced, while fierce winds are corm=.

Jan 1, 1984

By H. M. Ray

The discovery of the New Lead Belt in the mid-'50s began a search for mill design criteria that is continuously updated. The opportunity to design, construct, and operate four new mills in the span of 20 years provided fertile areas for new concepts. The central theme for design parameters encompassed simplicity, functional, and economic consideration. Ore characteristics for each plant remained relatively constant, providing stable criteria for grinding circuits. Bond index nominally 10-12. Flotation circuit parameters were based upon power application with 10-20% excess capacity built-in to protect recovery. Newer equipment exhibits greater power application efficiency lowering horsepower requirements per ton. Instrumentation was installed to stabilize circuits, protect equipment, and improve products. With ever increasing requirements of higher quality products, environmental considerations, and operating cost pressures, the upgrading of operating procedures is in a constant state of flux. Installation of more efficient equipment, chemical processing, or any other technique would be considered as feasible. Current practice is for St. Joe to design and engineer in-house its own plant design. The exception being detailing of structural steel. It is felt that familiarity with past design criteria serves as a valuable foundation to incorporate changes. Also, direct contact with operator provides specific data, and feedback for constructive criticism that is utilized for defining and correcting problems. The results are in reality an operator's plant with the benefit of advancing technology that meets the demands for improved products without sacrificing the economies of throughput or recovery.

Jan 1, 1977

By Carrie Smith

The Society for Mining, Metallurgy & Exploration’s annual conference and expo, MINEXCHANGE 2026, will take place Feb. 22–25, 2026, at the Salt Palace Convention Center in Salt Lake City, UT. The event will foster a hub for innovation, technical exchange and policy discussion for the global mining industry. Over four days, attendees will take part in short courses, technical sessions, field trips and networking events that highlight the advancement of the mining industry. The conference’s keynote session, titled “Regaining America’s Mineral Dominance,” will start at 8:30 a.m. on Feb. 23 in the Grand Ballroom E–J. The speaker will address the sweeping policy actions now shaping the nation’s mineral future, following a series of executive orders issued by the Trump administration designed to bolster domestic mineral production and energy security. These directives, including Immediate Measures to Increase Domestic Mineral Production (EO 14241) and Establishing the National Energy Dominance Council (EO 14213), have set in motion a coordinated effort across the Departments of Interior, Energy, Defense and Commerce to enhance the United States’ position as a global leader in critical minerals. The invited speakers include Utah Governor Spencer J. Cox and Nate Foster, managing director of Rio Tinto Kennecott, who will examine how policy and industry are converging to meet surging demand for minerals essential to modern technology. Governor Cox is expected to highlight Utah’s long-standing role in American mining, from the early development of Kennecott Copper to its current position as a producer of 40 of the nation’s 50 identified critical minerals. Foster, meanwhile, will offer insights into Rio Tinto’s extensive operations in Utah, including the Kennecott Copper Mine — one of only two operating copper smelters in the United States — and the company’s ongoing efforts to build more resilient, sustainable supply chains. Rio Tinto’s work in critical mineral production, from copper and tellurium in Utah to new operations in Arizona, has made it a fundamental figure in the U.S. mineral economy. Projects such as the Resolution Copper development and the revival of Gunnison Copper using Rio Tinto’s innovative Nuton technology illustrate how private-sector leadership is driving sustainability in domestic mining. These advancements come at a critical moment for the industry, as copper prices remain near historic highs. The keynote session will emphasize that meeting future mineral demand will require a concerted effort between government, industry and technology partners to secure responsible, domestic production. Immediately following the keynote, the Robert E. Murray Innovation Award Lecture will start at 10 a.m. as part of the same session. Lucy England, managing director at FLSmidth, will present on “Sustainable Copper Mining Flowsheets and the MissionZero Mine.” England, who has spent more than 25 years in mineral processing and innovation, will discuss how FLSmidth’s MissionZero initiative aims to develop the world’s most efficient

Feb 1, 2026

By CIM Mineral Resource, Mineral Reserve Committee

The CIM Estimation of Mineral Resources and Mineral Reserves Best Practice Guidelines (MRMR Best Practice Guidelines) were prepared by the Canadian Institute of Mining, Metallurgy and Petroleum's (CIM) Mineral Resources and Mineral Reserves Committee (CIM MRMR Committee) to update an earlier version that was accepted by CIM Council on November 23, 2003 (CIM, 2003). These 2019 MRMR Best Practice Guidelines supersede and replace the November 23, 2003 version of the MRMR Guidelines. These 2019 MRMR Guidelines are not intended to be prescriptive and are not intended to provide detailed and exhaustive instructions for preparation of Mineral Resource and/or Mineral Reserve (MRMR) estimates. Rather, they are intended as general guidance to assist professional geoscientists (or equivalent) and engineers (or equivalent) in preparing high quality estimates of MRMR that incorporate sound geoscientific, engineering, evaluation and design practices. They are based on well-established estimation and mine planning principles and are designed to provide general guidelines of best professional practices employed in the preparation of MRMR estimates. Although the 2019 MRMR Best Practice Guidelines are intended for use by Canadian-based mining/exploration practitioners, many of the concepts and practices presented herein are in general agreement with current industry practices in jurisdictions with membership in the Committee for Mineral Reserves International Reporting Standards (CRIRSCO). For this document, persons preparing MRMR estimates are called Practitioners. Preparation of MRMR estimates should be carried out by Practitioners who either hold the status of Professional Geoscientist (or equivalent) or Professional Engineer (or equivalent), or who prepare the estimates under the supervision of a Professional Geoscientist (or equivalent) or Professional Engineer (or equivalent). For the purposes of this document, all references to reporting describe such necessary reports and related documentation that are created as part of the normal-course work flow of preparing MRMR estimates for internal purposes. For clarity, all public disclosure of MRMR estimates made by, or on behalf of, an issuer and intended to be, or reasonably likely to be, made available to the public in a jurisdiction of Canada must comply with the requirements of National Instrument 43-101 Standards of Disclosure for Mineral Projects (NI 43-101), as amended from time to time. At least one Qualified Person (QP) must take responsibility for each part of the estimation process when publicly disclosing the results of MRMR estimates. The intended audience for these 2019 MRMR Best Practice Guidelines includes Practitioners at all levels of skill and experience, government agencies, academic institutions, and the public.

Nov 29, 2019

By Thierry Lavoie, Mark K. Larson

"Engineers at the National Institute for Occupational Safety and Health (NIOSH) and Itasca Consulting Group, Inc., conducted a study to determine the procedure for calibrating a caving model implemented in FLAC3D. The model is calibrated to measured surface subsidence. This sedimentary caving model was developed by Itasca for NIOSH for the purpose of more closely simulating mechanical processes during caving. When a model is considered calibrated to surface subsidence, the load between the extracted panel's roof and floor is a reasonable estimate of gob loading. Such information can also provide an estimate of the amount of overpanel weight that is transferred to the abutment. This load distribution is a parameter needed, for example, to estimate loading of pillars in longwall gate roads. For the current case, a calibrated model resulted in a calculated abutment angle of 30.6°considerably higher than the assumed value used in empirical methods, but reasonable considering the presence of massive stratigraphic members in the overburden. Because of additional information available after this study that the extracted seam height was actually greater in the first panel, a corrected range of abutment angle was estimated to be from 27.7° to 30.6°, still significantly higher than the empirical assumption. The expectation is that better estimates of abutment loading profiles will result in improved evaluations of mine layout design and, therefore, reduce the number of fatalities and injuries resulting from falls of ground.INTRODUCTIONThe safety of miners in underground coal mines depends on careful consideration of the mechanisms involved in failure and transfer of load. The successful design of pillars and panels in longwall and room-and-pillar coal mining requires thorough attention to any information and measurements available that help understand these mechanisms. Although empirical methods, such as Analysis of Pillar Stability (ALPS) Mark (1987); (Mark, 1992) or Analysis of Retreat Mining Pillar Stability (ARMPS) (Mark and Chase, 1997), can provide a sense of success or failure, complex geology and failure in the roof or floor material or complex material behavior of the coal can make evaluation by an appropriate numerical modeling tool necessary. The numerical tool must simulate important mechanisms and appropriate detail that underlie the mechanism. For example, Starfield and Cundall (1988) advised using ""the simplest model that will allow the important mechanisms to occur, and could serve as a laboratory for the experiments you have in mind."" To that end, data gathering about the geology, geometry, and material behavior is very valuable. Such data facilitate selection of an appropriate model and model inputs. Moreover, this data facilitate improved assessment of risk to miners and how to minimize that risk."

Jan 1, 2016

By William P. Harris

The Lincoln Terminal System is described as a device with the capability to deliver technical information, monitor student performance, and assure learning in industrial training. An experimental unit, the LTS-3S, was constructed and delivered to the Bureau of Mines with appropriate lesson material for a test of feasibility and acceptability of this form of training in the mining environment. Operations were conducted at two mine maintenance schools. The overall results were that (1) there was a substantial improvement between tests before and after self-training on the LTS, (2) students found this an acceptable way to learn, and (3) reaction by training personnel and supervisors was favorable toward the feasibility and advantages of using the LTS in the mining environment. Transfer of the LTS to industry depends on availability of reliable units and adequate lesson material. The requirements for authors of training materials were established based on advice from mine training experts, formal analysis of lesson development procedures, and experience from efforts in lesson development at Lincoln Laboratory-It was concluded that experienced mine training instructors were best qualified to proceed effectively and economically to format instructional material for the LTS, if supported by well-designed facilities and services. Discussion with mining experts confirmed the desirability of generating training materials and delivering instruction at distributed locations to meet local training needs and in direct support of industrial operations.

Jan 1, 1975