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By Peter Hornby, Maurice Craig, Franklin G. Horowitz, Don Bone

We have developed a high-performance, flexible scheme for interpolating multi-dimensional data. The technique can reproduce exactly the results obtained, for example, from Ordinary Kriging and related techniques in 3D, or from Thin-Plate Splines (Briggs' minimum-cuwature algorithm) in 2D. Moreover, com- pared to traditional implementations of these algorithms, our method enjoys large computational-cost savings. The new approach produces an interpolation that obeys a Partial Differential Equation (PDE). The PDE may arise from physically based arguments, but its form can vary widely. It might be specified only implicitly (as through a Model Variogram), or be nonlinear (although a performance penalty could then apply). While a formal equivalence between Kriging and Splines has been known for some time (Matheron, 1980), the present derivation, from radial basis functions, further illuminates this connection. Thus, for example, we can make explicit the PDEs that underlie some of the Model Variograms most often used in Geostatistics. Besides its practical utility, the work thereby ac- quires a theoretical interest.

Jan 1, 1996

By Shu Fan Chau, Innes Duncan, Harry Asche, Bill Newns

The North Auckland Line (NAL) in Northland, New Zealand, is being upgraded to pass Hi-Cube containers. The line includes many tunnels and bridges which need to be refurbished to improve structural clearances and line capacity. Tunnel 2 along the line, the Makarau Tunnel, has posed special challenges. Opened in 1898, the tunnel suffered multiple collapses during construction and has shown significant distortion during operation. The tunnel has been repaired many times since opening. Successfully enlarging this delicate and distressed structure has involved historical research, advanced analysis and design, and careful construction. The results provide lessons for dealing with brick lined tunnels and poor ground conditions

Jun 13, 2021

By George R. Stephans

The Climax Mine is a panel caving mine which has had a long history of incidents of severe ground control problems. The nature of the ore deposit, which lends itself to the caving meth- of of production, a1 so makes the mine susceptible to large scale stress concentrations which are referred to as ?weight? problems. These problems have increased with increased production and also with expansion to deeper mine levels. During the past twenty years the mine has had to learn to cope with these problems in order to remain in operation. A number of practical guidelines and useful techniques have emerged from these efforts. The purpose of this paper is to share a few of these ideas. The Mine is located near Leadville, Colorado on the continental divide at an elevation of 3450 meters. The ore body is a large low grade deposit of disseminated molybdenum sulfide. It measures about 1200 to 1600 meters in diameter and it had an original depth of about 660 mters. The Mine has been in operation since 1918 and the massive nature of the ore body together with its blocky, highly fractured condition made it natural for the caving system to have been adopted for production at an early date. Open pit mining was started in 1973. The total plant has a capacity of more than 50 thousand tons per day, and more than 400 million tons of reserves at an average grade of 0.310 percent molybdenum disulfide remain to be produced.

Jan 1, 1982

By H. -S. Yoon, C. -J. Kim, K. W. Chung

"With the final goal of ultrasonic application to ion exchange in a resin-in-pulp (RIP) system, the feasibility of an indirect ultrasonic application with a submersed ultrasonic probe was investigated first for the enhancement of ion exchange in the following resin-in-solution (RIS) system: Lewatit MonoPlus MP 600XL in an artificial solution with 106 ppm uranium. Ultrasonic radiation enhanced the ion exchange efficiency without mechanical degradation of resin. For 3.6 g/L of resin, the enhancement was 79 percent after 10 min of ion exchange and it gradually decreased to 11 percent at 60 min. In addition, a preliminary test of the mechanical stability of the resin in the RIP system showed little mechanical fracture of the resin due to ultrasound, which indicates that indirect ultrasonic application by a submersed ultrasonic probe is applicable for RIP systems. IntroductionIn uranium ore processing, the ion exchange process has been used on a commercial scale for preconcentration and purification (Gonzalez-Luque and Streat, 1984). The ion exchange process is divided into two processes: (1) a resin-in-column process with the uranium-bearing solutions passed through columns containing resins and (2) a resin-in-pulp (RIP) process with the leached ore pulp exposed to resins. The latter does not require the separation process of leach liquor and ore solids, which reduces process costs. This process, which has been developed commercially since 1955, has a certain drawback. The adsorption rate and efficiency in the RIP process are relatively low, so numerous contacts between resins and leached ore pulp are needed, which adds to the cost (Merritt, 1971). It is necessary to study methods to reduce process costs.Ultrasound can intensify mass transfer, increase the rate of chemical reactions, and change reaction pathways (Thompson and Doraiswamy, 1999; Luque de Castro and Priego-Capotem, 2007; Adewuyi, 2001; Luque-Garcia and Luque de Castro, 2003). It has great potential in chemistry and is especially considered to be a promising method for enhancing mass-transfer-limited processes, such as ion exchange. Enterzari and Tahmasbi (2009) reported the effect of ultrasound on water softening by ion exchange. Band et al. (1997) proposed a modulated ultrasound application to water desalination with ion-exchange hollow fibers. These reports revealed that ion exchange kinetics could be enhanced by the application of ultrasound. As for hydrometallurgy, Feng and Aldrich (2000) reported that the elution of an ion exchange resin was enhanced by the use of ultrasonication."

Jan 1, 2015

By J. Armstrong, J. Bourgeois, S. Warren

The application of statistical analysis software programs has proven useful for investigation of rockfall runout distance along a designed slope. Rockfall modeling programs are continually being upgraded with more sophisticated analysis tools, such as the use of the rigid body versus lump mass models. Engineers at mine sites utilizing the software may have varied experience related to these models, their associated input parameters, and how to interpret the generated results. To address this concern, researchers at the Spokane Mining Research Division (SMRD) of the U.S. National Institute for Occupational Safety and Health (NIOSH) investigated the influence of slope height, slope angle, slope material, and rock size for both rigid body and lump mass models in a 2-D statistical analysis program. Based on a literature search and industry input, specific ranges common to that of an open pit mining environment were chosen for each of the input parameters to determine 90% rock runout distance as well as their sensitivity to change. Data collected from this numerical analysis and simulation will be compared to empirical rockfall data gathered through the duration of the Highwall Safety project conducted by NIOSH from 2022–2026.

Mar 2, 2022

By Carl R. Peterson

The Rapidex continuous drill and blast tunneling concept utilizes a unique spiral blasting pattern that permits efficient performance with relatively small single shots, while at the same time directing major blast fragments at right angles to the tunnel axis. The concept's self-shielding geometry permits the design of a lightly shielded machine that can stay at the tunnel face firing frequent small blasts to provide rapid, virtually continuous advance. This paper describes Phase III of the development program (supported under Bureau of Mines contract H0252047) in which the "front end" of the machine?drilling loading, and shooting components, together with the shield--was fabricated and field tested underground at the White Pine Copper mine, Michigan. One of the major accomplishments of the Phase III effort was to develop a fully remote controlled loading and initiation system in which explosive slurry is pushed, through a hose into the blasthole by a small water-driven piston carrying the blasting cap. The cap is ignited via an induction coil just prior to entry into the borehole, after which a delay permits complete -withdrawal and shielding of the loading hose. The ultimate objective of the present Bureau-sponsored program is to evaluate the feasibility of mechanizing hard rock mining operations, such as development to a point where drilling, loading, shooting, and mucking can proceed simultaneously and result in increased productivity.

Jan 1, 1977

By Brian W. Mackenzie

The mine development decision is made on completion of exploration to determine whether or not a mineral deposit should be developed to production and, if so, how. This involves the selection of an optimum mine development alternative from a number of technically feasible alternatives and the comparison of this optimum with those of other available investment opportunities. If the optimum is sufficiently attractive, the deposit is developed to production. The selection process is carried out within a framework of corporate objectives and resources. The mine development decision is based on the balancing of two parameters - - rate of production as reflected in plant capacity and cut-off grade. On the basis of available information and experience, detailed revenue and cost 'estimates are made for each feasible combination of plant capacity and cut-off grade. What economic evaluation techniques should be applied to these estimates to reduce each alternative to economic indicators that will enable meaningful comparisons and an informed investment decision? This is the essence of the paper. The determination of optimum plant capacity and cut-off grade has been the subject of intensive research efforts by economists and mining engineers (1-7). Their studies are based on marginal analysis and assume that, at the time of decision, certainty conditions prevail with respect to ore reserves, mining costs and mineral markets. The optimum mine development alternative is defined as that which maximizes profitability.

Jan 1, 1969

By William Gleason

"Speakers and attendees of the 2016 Cutting Edge Conference could not be faulted for keeping one eye on the presentations taking place at the Hyatt Regency at LAX in Los Angeles, CA on Nov. 7 and 8 and another on the results of the historic election in the United States that took place on Nov 8. While there was certainly interest in the presidential campaign, there was also a great deal of interest in Measure M on the California ballot. Measure M, which passed easily, is a half-cent sales tax increase that will fund the most ambitious transit expansion in Los Angeles County history.In the coming years, the ballot measure will transform a traffic-choked region by funding the construction of nearly a dozen new rail lines with an estimated $120 billion raised in four decades. Among the projects that could come to fruition are a twin-rail tunnels project through the Sepulveda Pass and new connections in the city.During the update on West Coast projects, Bill Hansmire summed things up with a slide asking “How much work is there on the West Coast,” and his answer was “Billions.”From Seattle, WA south to Los Angeles, there is already a lot of work for tunneling and underground construction experts, and Measure M ensures that there will be plenty of work for decades to come.Currently, The Los Angeles County Metropolitan Transportation Authority (Metro) has three rail projects underway that were funded by Measure R in 2008 — the Regional Connector, the Purple Line subway extension and the Crenshaw/LAX Line that are designed to alleviate the traffic pressure with an eye to more solutions.Measure M is the fourth sales tax increase to fund transportation in L.A. County, bringing the base sales tax rate to 9.25 percent. In some cities, which already levy their own sales tax, the rate would be higher, The Los Angeles Times reported.About 35 percent of the revenue will fund major new transit projects, such as the subway under the Sepulveda Pass, extension of the Gold Line to Claremont, extension of the Crenshaw Line to West Hollywood and acceleration of the Purple Line Subway construction along Wilshire Boulevard to finish in 2024, 10 years earlier than scheduled.About 17 percent would fund a dozen highway improvement projects, such as widening parts of I-5 in the Antelope Valley and southeastern county, adding bus lanes to the Sepulveda Pass section of the 405 freeway and adding truck-only lanes to a section of the 710 freeway."

Dec 1, 2016

By J. R. Sims

Gold assays from production blastholes in the Mercur Hill Pit were used to delineate known ore zones and to determine how well previous exploration drilling defined these zones. The most important factors causing inadequate ore zone definition were: 1) inappropriate location of drill holes relative to the ore zones, 2) presence of stopes from previous mining, 3) sampling and assaying errors, and 4) smoothing of the ore zone boundaries during ore reserve estimation. Infill drilling strategies were evaluated to determine the efficiency with which a given drill pattern defined the known ore zones. A drilling strategy was developed which improved ore zone delineation when compared to techniques which maintained uniform drill spacing.

Jan 1, 1992

By P. M. Soupios

A near geophysical surface investigation of a landfill area close to the Hania city, in Crete Island, Greece, was conducted as inextricable phase of a preliminary geotechnical, geological and hydrogeological study of the area under investigation. Electrical Resistivity Tomography (ERT), one of the most promising prospecting techniques mainly concerning its effective contribution to resolve several environmental problems, was applied for the geophysical modelling. ERT is a robust imaging method the theory and implementation of which are well documented in geophysical research literature. The survey site is located in Akrotirion Peninsula, about 7km east of Hania city in Crete I. The geological setting comprises Trypalion limestones, marly limestones and a clayed weathered layer. Cavities are also identified at various scales which are recent tectono-karstic voids resulted from the combined actions of karstic erosion and tectonic stress on the Trypalion limestones where they are located. Due to the above-mentioned geological singularity and in the light of the requirement for an environmentally safe construction of the landfill, an ERT survey was carried out by deploying the dipole?dipole electrode configuration. Specifically, seven geoelectrical tomographies were conducted reaching the prospecting depth of 36m. The resulted images conduced, a) to overcome geotechnical problems, b) to plan the future sites for waste disposal and c) to reliably estimate the thickness of the already deposited wastes.

Jan 1, 2005

By Jon Bowler

Daw Mill Colliery, UK Coal, near Coventry in England, mines the Warwickshire Thick Seam at 800 m/2500 ft depth using longwall retreat with gateroads supported by rockbolts. Over the last eight years the mine has worked longer and wider panels with extraction heights of over 5 m. Recently the mine has experienced high deformation conditions principally from the rib sides resulting in operational issues and production delays. Investigation of rib deformation was undertaken using new inspection and measurement techniques, including systematic laser surveying, and improved rib support consumables were developed and introduced. A new rib trussing system using textile webbing has proved very successful.. A rib support management system was also developed and introduced for face retreat. This allowed rib support to be more effectively managed both for production and safety. For the current developments, new 28-mm-diameter roof and rib bolt systems have been introduced and rib bolt length has been increased to 3 m, with the aim of achieving gateroad stability over the life of the panel. Significant reductions in roof and rib deformation have been confirmed by the latest monitoring results. These ground control innovations are allowing Daw Mill?s potential to be realised. Production from 302?s face in 2008 set new UK and European records. However the support enhancement process continues and further innovations are planned.

Jan 1, 2009

By Anil K. Ray

Roof falls are one of the greatest hazards in underground coal mines worldwide. Due to stringent safety measures and extensive support system development, roof falls have been reduced significantly but they still persist in many underground coal mines. Some of the roof falls initiate with cutter roof or guttering. In the past, many factors have been identified as being responsible for the development of cutters and roof fall. These responsible factors can be broadly classified as stress related or non-stress related. In this paper the finer details of mining technique have been taken into consideration for better understanding of cutter roof and roof fall problems. Three dimensional finite difference modeling has been used to explain the mechanism of cutter development. Strain softening material behavior has been used to realistically simulate the cutter formation, and common cutting sequences as implemented in the field have been simulated. This was done with an objective to determine whether the cutting sequence has really any significant control over cutter formation or not. In addition to cutting sequences, the effect of cut length is also studied. The effect of step cutting and turning of crosscut into and away from major and minor horizontal stresses is also examined to see its influence on cutter development.

Jan 1, 2009

By J. Stachulak

This paper deals with theoretical considerations and practical applications of ventilation network calculations, based on mass flow rates and performed by computer simulation in our deepest operating mine - Creighton. The paper also deals with natural ventilation. In the usually accepted air-flow theory, the air is assumed to behave like an incompresssible medium. This introduces considerable error where temperature and pressure changes are great. Therefore, any study of the air flow in deep mines, must take into account compressibility. Basing ventilation calculations on mass flow allows a distinction to be made between air leakage and such quantity changes which occur due to air density changes. The energy which is required to convey one pound of air through a mine can be obtained by adding all head losses hL (ft-lb) of the ventilation paths through which the air flows. However, this total energy will not be correctly expressed in a compressible fluid by summing all pressure losses PL = hL x d (ft-lb/ft3 = lb/ft2) d = density. There is a law of mass conservation, but no law of volume conservation. Natural ventilation is caused by the conversion of heat into mechanical energy and not by the difference in upcast and downcast densities, as often believed. In an existing mine natural ventilation can be determined correctly by plotting a pressure volume diagram and measuring the area ? [ ] vdP = hN, where v = specific volume, or by measuring the sum of all friction losses and work provided by a fan. These procedures are tedious. The natural ventilation head (hN) can be approximated by the equaticn hN =[ ] tdZ. Where T is the average absolute temperature, t air temperature and Z elevation. In Prof. R. Greuer's computer program this determination of hN is automatically done for every mesh of the network.

Jan 1, 1980

By A. A. Compoli

Injecting water under pressure to wet the coalbed in advance of mining reduces mining-generated respirable dust. Owing to economic and geological barriers, water infusion for longwall dust control in the United States is currently limited to the Pocahontas No.3 Coalbed in Virginia. Water is pumped into the coalbed through underground boreholes drilled horizontally from the headgate toward the tailgate side of retreat longwall panels. This paper theorizes that the barriers to widespread utilization of water infusion for longwall dust control could be overcome by long-duration, low-pressure water infusion through vertical gob gas boreholes. Currently, 43% of the 72longwall mines in the United States employ vertical gob gas boreholes. Computer coalbed reservoir simulation suggests that one vertical surface borehole could infuse the same longwall panel area as four horizontal boreholes in the current water infusion system for longwall dust control in the Pocahontas No.3 Coalbed.

Jan 1, 1995

By William V. Robinson

The Iron Ore Company of Canada mines, processes and ships crude iron ore, concentrate and pellets from the rich ore bodies of the Labrador Trough area in the extreme north-eastern part of Canada, some five hundred miles from Montreal (see figure 1). There are three main sites of activity. At Schefferville, approximately 12 million tons a year of crude ore (chiefly limonite) are mined, crushed, screened and shipped to Sept-Iles. At Labrador City, 40 million tons of specular hematite are mined annually for processing into 17 million tons of concentrate. Of this, 9 million tons are converted into pellets. All product 1s shipped to Sept-Iles. At Sept-Iles, on the north coast of the St. Lawrence, a six million ton per year concentrator and pellet plant process much of the Scheffervllle ore into high-grade pellets. Also at Sept-Iles are the company's administration offices stockpiles and shipping facilities. The Terminal facilities can berth and load a 250,000 ton bulk carrier at 19,000 tons per hour.

Jan 1, 1975

By Leena Suopajärvi, Karin Käär, Marcin Szumny, Jari Joutsenvaara, Md Ariful Islam, Helmut Mischo, Georg Meissner, Ossi Kotavaara, Catalina Vrabie

This study outlines implemented tactics and results for community empowerment through participation in questionnaire surveys, educational programs, and discussion on sustainable sourcing from new critical raw materials (CRMs) projects. Utilising questionnaire surveys, including the Public Participation Geographic Information System (PPGIS), the research gathered public opinions from Estonia, Germany, Poland, and Zambia, receiving 1,068 responses. These responses addressed various social, economic, and environmental issues related to CRM projects. Feedback from educational courses with participants from over 25 nations and public events provided additional insights. The collected data and feedback offer crucial input for advancing sustainable and responsible CRM sourcing strategies in these regions.

Feb 1, 2025

By H. Colijn

Vibratory or oscillatory conveyors can be found in all types of industry, handling virtually any granular bulk material, often at elevated temperatures. These conveyors can be combined with other process functions, such as screening, cooling, drying and dewatering, while conveying. Although construction and installation is relatively simple, the engineering and design analysis of the vibratory mechanics is fairly complex. This paper will discuss the basic types of vibratory conveyors and the analysis of the material movement along the carrying trough.

Jan 1, 1985

By T. Gupta, T. Ghosh

Rare earth elements (REEs) and their compounds are essential in a multitude of mundane and sophisticated applications such as renewable energy technologies, catalysts, medicine, and defense applications. The global supply deficit could be attributed to the destabilization of REE market that has, as a result, incentivized indigenous production of REEs. Cost-effective and environmentally benign opportunities are being explored for the production of REEs from non-conventional mineral sources including coal and coal by-products to stabilize the supply chain. Coal from Healy coal mine and Wishbone Hill deposits in Alaska have been quantified for REEs and were found to possess elevated total REE concentrations as compared to world average levels (60– 70 ppm). The objective of the study was to concentrate the REEs in the froth phase by froth-flotation of the fine size fraction (< 75 μm). A Box-Behnken design of experiment was employed to ascertain the main and interaction effects of operational parameters on response variable by analyzing 3D response surfaces. Experiments were carried out to maximize REE recovery and concentration by modeling and optimization of three operating variables (frother dosage, pulp density (% solids), and collector dosage). Based on the results, the optimum flotation conditions for maximum recovery at an elevated concentration of REEs in the froth fraction was obtained at 4.2% solids and 32.7 ppm of frother dosage for Healy sample and 10% solids and 37.9 ppm of frother dosage for Wishbone Hill coal sample. The quadratic relationship between the input and response variable was found to be independent of collector dosage suggesting good surface hydrophobicity and floatability of the two coal samples.

By Walter von der Linden

On April 14, 1975, Consolidation Coal Company began to operate a longwall face in their Shoemaker Mine using shield supports. This was the first time that shield supports were used in the United States (1) 1/. Shortly thereafter, Kaiser Steel Corporation started a shield longwall face at their York Canyon Mine (2). From October 1975 through May 1976, three more longwall faces were commissioned in mines located in south-western Pennsylvania and northern West Virginia. In June 1976, four installations had completed their first panel and two installations had completed the subsequent move to the second panel where coal production is now well under way. During this time (April 75 to June 76) the total number of shield support face operating months, including moving time, was 40 and the combined face advance was approx. 17, 000 feet (5200 m) with face lengths varying from 450 - 550 feet (137 - 168 m). While the shield support experience in the U.S. is still limited on the basis of time and mining parameters, the operating results of all faces have been very satisfactory. New record 24 hr production figures were set and - far more important - long term production figures could be sustained on an impressively high level even when taking face moving time into account. The purpose of this paper is to review the performance of shield type supports in the U.S. and to assess their value as longwall supports for U.S. underground mining conditions with regard to roof control, maintenance, operator convenience, safety and productivity.

Jan 1, 1976

By Werner Bilfinger, Claudio Nahas, Marcelo Waimberg

"INTRODUCTION The so called Porto Maravilha Project consists of the re-urbanization of a 500 ha area in the Rio de Janeiro port region. Several changes in local infrastructure are being implemented, including a significant change in the road system, with the demolition of the former “Via Perimetral” viaduct and construction of 4 new tunnels: • Saúde tunnel - 35 m long (Waimberg et al, 2014); • “Binária tunnel” - 1012 m long; • “Via Expressa” twin tunnels - 1850 m long each way. The tunnels were excavated almost completely in rock using conventional drill and blast methodology and only some short stretches in weathered rock, associated to faults zones, residual soils and marine sediments close to the tunnel portals. During excavation of access shaft and “Via Expressa” and “Binária” tunnels significant ground settlements as well as settlements of buildings founded both on shallow and deep foundations were measured. These values could not be associated to conventional tunneling induced settlement troughs. This paper focuses on the “Via Expressa” tunnels, presenting a brief description of the project as a whole, its geological and geotechnical background, monitoring results, and a discussion of possible causes of the measured settlements. PROJECT DESCRIPTION The Porto Maravilha Project is an integrated multidisciplinary action on behalf of the Rio de Janeiro city council with support from the State and Federal Governments. In addition to creating new conditions for working, housing, transport, culture and leisure for the resident population, it also promotes expressive economic development in the region (Portonovo, 2015). Porto Maravilha Project is carrying out actions for the recovery of the region’s historical heritage, as well as promoting the population´s social and economic development. One of the main benefits of the Porto Maravilha Project is the construction of the new traffic system in the port area, consisting of the Express and Binário roadways. The new project, which will replace the current Perimetral Rodrigues Alves viaduct system, will increase traffic flow capacity by 27%."

Jan 1, 2016