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By Fred T. Towne

There are a number of air classifiers manufactured throughout the United States and the rest of the world. The classifiers manufactured by Alpine, A. G. of Augsburg, Germany, are unique in their abilities. It is this uniqueness that I wish to delve into and in this respect we will limit this discussion primarily to the classifiers as manufactured by Alpine. It has been reported in the past that these classifiers were introduced into the. United States in the late 50's. Until the introduction of the Alpine Classifiers, air classification seldom produced a satisfactory fractionation of a product below 45 microns (325 mesh) or above approximately 22 mesh. It has been a common practice to classify fine materials which used water as a carrier medium The use of centrifuges are today producing thousands of tons of finely partitive powders in the very small particle size range. The use of centrifuges in connection with wet grinding mills has increased the rates of production of these mills considerably.

Jan 1, 1965

By J. M. Applegate

In the same way that a blueprint communicates information about a structure, a useful systems architecture should provide information that guides the construction and implementation of computing systems. Taking the blueprint analogy a step further, a plot plan can also show where in the "bigger picture" a particular design fits (if in fact it does) and what a builder needs to know about the environment in which he or she will operate. In the context of business systems, a meaningful architecture should convey the following: 1. The primary purpose of computer based systems relative to particular task or operation. 2. The relationship of systems to each other and an indication of their interaction and dependencies. 3. The relationship of systems relative to the organization and its objectives. 4. Indications of where IS/IT resources can best be allocated to support the organization. 5. The overall context in which new systems and technologies can be assessed for both their impact on current system and on the organization itself.

Jan 1, 1998

By J. H. Daniel

Dust-related respiratory disease remains the major health concern in mining, and health agencies are proposing more stringent standards. The U.S. Bureau of Mines (USBM) is investigating techniques to continuously monitor respirable dust in real-time during the coal or ore extraction process. Continuous monitoring will allow mine operators to evaluate hazardous dust concentrations and adjust the operations to produce less dust. Mine instrumentation applications include machine-mounted and hand-held monitors, personal monitors, and area/environmental monitors. Six dust detection methods have been considered to meet application requirements. These are: light-scattering instruments, a smoke-particle detection technique, correlation of pressure drop across the collection filter with amount of dust deposited, the Tapered-Element Oscillating Microbalance (TEOM) instrument, a method that relates the amount of dust collected on a filter with the vibration of the filter, and beta attenuation measurement of dust. Studies to date have identified the TEOM instrument and the technique of correlating the amount of dust collected with the vibration ofthe filter as having the most promise for success. Development of the machine-mounted monitor is the highest research priority. The application options and progress to date in developing continuous monitoring instrumentation are presented.

Jan 1, 1995

By David I. Smith, Kenneth Arnold, Bryan Aweh, Vincent Falkowsk, Brian Lakin, Andy Fer

Nassau County, New York, is undertaking several projects to improve the water quality in the Western Bays of Long Island. A major step forward will be the completion of the Bay Park Conveyance Project, which will divert most treated effluent away from the Western Bays to an existing ocean outfall at the Cedar Creek Water Pollution Control Plant. The ongoing works include 3.6 miles of microtunneling, 7 miles of sliplining, 14 shafts, and a 75 MGD pump station. This paper provides an overview of the design and an update on construction progress through December 2022. The project is a collaborative effort between Nassau County, New York State Department of Environmental Conservation, the design-builder, and various consultants.

Jun 13, 2023

By James F. Albus, Vincent C. Grimshaw

High pressure fluid energy grinding, or jet milling, is a versatile method of continuously fracturing solids into fine particles to gain substantial increases in exposed surface area Applications in industrial minerals grinding include calcium carbonate, talc, barytes, mica, diatomaceous earth, bauxite, rutile, coal, kaolin, sepiolite, diamonds, etc The basic principles can be extended to provide continuous drying and delivery of discrete par¬ticles from a wet process slurry The main design and operational features of jet mills and dryers are described, relating energy consumption for both air and steam milling and hot air drying techniques Mean particle sizes in the order of 1 micron are achievable from pre-milled feeds, or maintained from similar slurries in the drying mode Aspects of feed preparation and multi-stage processing are discussed

Jan 1, 1983

The methods used by Newmont Gold Company for deposit modeling are illustrated by examples taken from current operations and advanced projects. These methods vary depending on a number of factors, including geology, mining and processing methods, economic feasibility, and availability of historical information. It is argued that successful modeling requires understanding these factors, knowing the strengths and weaknesses of the various modeling techniques, and being flexible in selecting the appropriate methods.

Jan 1, 1997

By Jackson G. Jenkins

Magma Copper Company's San Manuel SX-EW facility has operated since May, 1986. The original facility had a design capacity of 25,000 tons per year of electrowon copper cathode produced by processing pregnant leach solution from an open pit/heap leach operation. In 1988, the plant was expanded to 50,000 tons per year to incorporate processing in-situ leach solutions. This paper focuses primarily on the heap leaching area with regard to exploration, testing, feasibility, permitting, design and construction, and operating practices. Research utilizing surfactant leaching aids to enhance copper recovery is also discussed.

Jan 1, 1993

By Mike Hall, Tim Kelly, Mohammad Reza Jafari, Ulf Georg Gwildis

"Qatar’s capital Doha is undergoing major infrastructure improvements including a multiphase stormwater management program. Although located in an arid climate, Doha experiences flooding during rainfall events. Dewatering operations and rising groundwater levels add to the management needs. To address those needs, construction of the Musaimeer collection tunnel along Doha’s southern rim is being followed by a marine outfall tunnel connecting a pump station to a dispersion field 10 km offshore. Qatar’s geology is characterized by sabkha deposits, a series of predominantly weak and karstic rock strata that creates challenging conditions for mechanized tunneling, as highlighted by the uncontrolled flooding of a tunnel boring machine (TBM) used on the Doha Metro tunnels. Risk associated with these challenges is magnified for the outfall tunnel by drive length, sub-sea elevation, and a single access point. This paper describes the outfall exploration strategy and design decisions made in light of experience gained during the collection tunnel construction. CONTEXT – STORMWATER MANAGEMENT PROGRAM Qatar has an arid climate with an average annual precipitation of less than 100 mm. Precipitation is mostly confined to the winter months when rare, but occasionally heavy rainfall events easily lead to flooding in Doha’s metropolitan area. Its coastal location and flat topography a few meters above the sea level mean that the depth to the groundwater table is generally shallow. The karstic aquifers in the regional dolomite and limestone series contain groundwater of high salinity, which is not suitable as a potable water source. For supplying Doha’s population of more than 900,000 (2014) with potable water, the Ras Abu Fontas seawater desalination plant is operated about 10 km south of the city. This potable water production capacity is crucial for Doha’s development and – in conjunction with overirrigation and leaking sewage tanks – is also the root cause for rising groundwater tables that have been observed over the past years."

Jan 1, 2016

By David J. Barr

Public Law 91-190 - January I, 1970 states that, "The purposes of this Act are: To declare a national policy which will encourage productive and enjoyable harmony between man and his environment; to promote efforts which will prevent or eliminate damage to the environment and biosphere and stimulate the health and welfare of man; to enrich the understanding of the ecological systems and natural resources important to the Nation; and to establish a Council on Environmental Duality." The administrative aspects of this National Environmental Policy Act of 1969 have in essence established the requirement that all agencies of the Federal government assess the consequence of their actions with an Environmental Impact Statement. Furthermore, five states have already enacted environmental legislation, and others will surely follow. The Environmental Services Project Director for Dames and Moore has stated in the June issue of that company's publication, "Elements," that, "The nuclear power industry has perhaps been most affected to date by the Act [NEPAL but recent court decisions, legislative trends and general public concern will accelerate the spread of the Act's impact on other industries. Mining and petroleum are already involved in environmental affairs." There can be little doubt that within a very short time all environmental aspects of the minerals industry will be strictly regulated and monitored by some agency of Federal and/or state government. Indeed, it is probable that any future effort to extract natural resources will be contingent upon a favorable review of an Environmental Impact Statement. It is also quite possible that continuation of present operations will have to be justified on the basis of proof of an acceptable environmental impact. It is the objective of this paper to present some ways in which remote sensing technology can be applied toward an efficient collection of environmental data necessary for the preparation of an Environmental Impact Statement.

Jan 1, 1972

By D. W. Park

Longwall mining is popular in underground coal production in the United States due to higher production rates and safety concerns. Because of the extreme complexity, it is necessary to plan an adequate design to achieve a safe and efficient working place. The proper sizes of yield and abutment pillars and panels can be determined by simulation using numerical modeling techniques. By means of three-dimensional modeling, stresses to be imposed on the pillars, panels, gob, and powered supports can be analyzed. In this study, an initial three-dimensional finite element model was developed and then modified into four different models. Using these models, the numerical outputs of distributed stresses on three different sizes of yield pillars, three different sizes of panels, and two different sizes of abutment pillars were compared and analyzed to determine the most adequate pillar and panel sizes. Progressive failure theory based on the Hoek and Brown failure criterion was used to determine redistribution of stresses in the yielded and failed areas in the longwall mine.

Jan 1, 1992

By H. V. Scotland III

Lafarge Corporation's Texas Quarry, in Baltimore MD, achieved a substantial expansion of pit reserves by removing an inactive underground mine. The day lighting program, designed, and completed in 1997, open pit mined more than 400 meters of room and pillar workings which were originally developed to recover high brightness Calcium Carbonate. The project proved to be a challenge throughout its course as the pit plan was modified and successful daylighting techniques were developed to remove the mine without adversely affecting the safety of the operation, quality of the stone recovered, or negatively impacting the surrounding community. The design parameters and techniques developed and implemented at Texas may prove of interest to other operators as they are faced with daylighting opportunities. This article will detail the challenges we faced and the solutions which made the project a success.

Jan 1, 1999

By Thomas R. Kuesel, Harvey W. Parker

INTRODUCTION This paper describes the use of a shield and compressed air for construction of a short section of a pair of twin single-track tunnels for the Metropolitan Atlanta Rapid Transit Authority (MARTA) transit system. Although only two blocks long, this section posed the greatest difficulties to both engineers and contractors, and is the most expensive section of line construction on the MARTA system. All this derives directly from its setting--these tunnels had to be constructed through mixed-face conditions. SETTING The Broad Street tunnels form a link between the Peachtree Center and Five Points Stations, in the heart of Atlanta's central business district (Figure 1). Peachtree Center sits atop a solid rock ridge, which inspired the design of a deep rock-mined station, as described in the 1979 RETC. Five Points Station is MARTA's hub--the intersection of the system's two main branches. It is located in the old railroad gulch, a filled-in erosional valley at the base of Peachtree Ridge, and was constructed by open-cut methods. The alignment and profile of the Broad Street tunnels were closely constrained by these two adjacent anchors, and in the six-block stretch between them there was very little room for maneuvering. Since the rock ridge petered out about in the middle of the section, it was evident at the outset that there would be about two blocks of rock tunneling at the north end, two blocks of soft ground construction at the south, and two blocks of mixed-face in between. It is this central two-block section that is the focus of this paper.

Jan 1, 1981

By Allegra Yeley, Ted Klemetti, Gamal Rashed, Tim Miller, Nicole Evanek

In 2015, the Subtropolis Mine in Petersburg, OH, experienced a massive ground collapse that continues to grow over time. Horizontal stress effects have affected the roof at this operation in the past and may have played a large role in this collapse. Horizontal stress can impact the roof and floor stability and endanger the health and safety of underground stone miners. Mines experiencing damaging effects from horizontal stress typically find that the principal stress direction is the same throughout the mine and the region. At the Subtropolis Mine the principal horizontal stress direction appears to change as conditions change and differs from the regional horizontal stress, particularly near the collapse or other roof fall areas. The growth over time of this collapse and other roof falls have been captured and analyzed using geologic mapping, 3D LiDAR scanning, numerical modeling and geographic information systems like ArcGIS. Utilizing these tools to better understand sitespecific conditions can be critical to reducing the potential of massive ground collapses in the underground limestone industry.

Feb 1, 2024

By L. Boyd, T. Martin, V. Gall

Water infiltration into subgrade infrastructure can cause major impacts on their performance. In addition to damaging the structure, water intrusion leads to deterioration of installations including electrical and mechanical components and in patron discomfort. To remedy these impacts, leak remediation is often carried out to halt water infiltration. Remediation methods include coatings, drainage, injection/stitch grouting, curtain (backside) grouting, and/or internal umbrella systems. Selection of the rehabilitation method depends on the structure’s use, owners’ priorities, its installations, structural conditions, surrounding ground, and hydrogeologic conditions. Since many factors influence the rehabilitation method chosen, a novel holistic approach is undertaken to understand leakage causes and consequences to develop the most appropriate, efficient, and reliable solution to extend the structure’s life. A reconnaissance phase combines geologic, hydrogeologic, and as-built information with detailed digital scans and visual observations to develop a database of existing conditions. This database, called a tunnelband, is used to develop the rehabilitation solution and made part of the contract documents, allowing for an informed bid by specialty contractors. Tunnelband and the preferred rehabilitation system are portrayed in contract documents, which are procured in various contract types depending on the owner’s preference and project characteristics. The pool of contractors are required to submit their understanding of this holistic approach by developing and supplying the owner with a detailed workplan. The completed rehabilitation is portrayed in detailed as-built drawings which also provide the owner with an operation and maintenance manual outlining for periodic observation of the structure and checking of its performance. Ultimately, this information is implemented into a “BIM Digital Twin” that is used by the operations and maintenance staff for long-term observations. This proposed novel framework for leak rehabilitation is currently being used successfully in a number of projects throughout the United States.

Jun 13, 2023

By Ricky Chipka, Roshan Thapa, Richard Yovichin, Greg Rogoff, Patrick Niemuth

A 4.5-mile-long, 96-inch-diameter outfall pipeline was constructed between North Texas Municipal Water District’s proposed Sister Grove Regional Water Resource Recovery Facility and the Stiff Creek Discharge Structure. Two TBM-mined tunnel segments were excavated for the outfall pipeline through rock and mixed-face conditions within the Austin Chalk Formation. The TBM mining performance was tracked in detail and evaluated during mining. This paper discusses the TBM configuration, TBM utilization, advance rates, and challenges of both tunnel segments.

Jun 13, 2023

By Haydn H. Murray

Kaolins and bentonites of economic importance in Australia and New Zealand are described. Clays that are used for structural clay products are not discussed. Residual, hydrothermal, and sedimentary kaolins are utilized including clays associated with coal measures. Bentonites are sedimentary and residual. Very little kaolin and no bentonite is exported presently, but this will change in the near future as transportation costs continue to escalate. Many areas of Australia, in particular, where kaolins are known to occur have not been investigated to determine the quality and quantity of the deposit.

Jan 1, 1982

By Steve Kral

The list of environmental issues facing industry in general, and the mining industry in particular, has placed greater emphasis on the concept of risk assessment and risk management. In informal terms, risk can be defined as the chance of injury, loss or damage. More formally, it is defined as the probability of an occurrence and its consequences. In simple terms, risk assessment involves three questions: What can go wrong? How probable is it to go wrong? If it goes wrong, what are the consequences? Experts on the subject of risk assess¬ment and management met in St. Louis, MO in October 1992 to discuss the extensive and innovative technology that has been developed in this arena. Each agreed that a consistent framework can be used to approach risk assessment/ management considerations in siting and design alternatives, as well as when considering financial aspects of mine development. And the environmental planning process for mines, as well as planning for operation through closures, will rely more heavily on risk assessment and management techniques. Risk assessment is a tool to assist engineers, scientists and managers make better, defensible operational decisions. A realistic and probabilistic risk analysis, coupled with a sound financial model, can combine a large set of alternatives and criteria to arrive at a defensible decision. Organizers of this regional SME conference believe that mining professionals should become fully conversant with risk assessment techniques and approaches because this arena provides opportunities to develop more rational decision-making techniques. Current health risk assessments rely heavily on Environmental Protection Agency (EPA) approaches. Several speakers and papers show how this approach has been applied to a variety of topics. Two major advantages come forward when applying risk assessment techniques to environmental clean-up options for contaminated sites. They are the selection of practical options and cost-effective alternatives. A probabilistic risk assessment provides results that can be directly related to clean-up costs. It has been shown that small reductions in risk are obtained for large increases in cost after a certain threshold value is reached. A preferred, practical clean-up alternative that provides permanent solutions can be selected based on a probabilistic assessment. Here are summaries of some of the papers presented at the meeting.

Jan 1, 1993

By E. B. Kroeger

One of the problems encountered when constructing a roadway is the planned route often needs to cross soils that are soft and highly compressible. An approach to dealing with soft and compressible soils is to construct the fill from lightweight materials, thereby reducing the stresses on underlying soils. Most lightweight fills have approximately the same cost, so the most important consideration when choosing a lightweight fill is that the material properties of the lightweight fill match the conditions existing at the site. Expanded polystyrene (EPS) has been used as a lightweight fill material for more than 30 years. The EPS used for road fills is typically in the range of 0.5 to 2 lb/ft3, and has a compressive strength of in the range of 10 to 30 lb/in2. If a higher strength material is needed, then the material density is increased, which also adds to the cost of the material. Another type of lightweight fill material that is commonly being used is lightweight aggregate (LWA). LWA can be created by passing slate or shale through a rotary kiln or reheating coal fly ash with other materials to form pellets or aggregate. Several companies throughout the U.S market these materials under a variety of names. LWA can have a unit weight from 45-80 lb/ft3. For sites where trucking granular fill does not pose a problem, this material may be an alternative to EPS. One of the drawbacks to using LWA is the availability of the material. Only a few companies are manufacturing LWA, so it may not be available or may be cost prohibitive in certain areas of the country. Lightweight flyash blocks have been produced which may fill the gap in unit weight between the EPS and LWA. Blocks have been produced with a unit weight as low as 30 lb/ft3. They are relatively inexpensive, easy to handle, and have a moderate compressive strength. Although the unit weight is dramatically higher than EPS, the strength is also higher. If lateral stabilization of the fill is a problem, then geofabrics or grids can be incorporated into the design to add lateral strength.

Jan 1, 2003

By Frank Hagar, George M. L. Robinson

INTRODUCTION Mine waste monitoring and management is essential when the industry is being required to accept the environmental liability for all generated, stored and disposed solid and hazardous waste. Environmental regulations mandate the operator to minimize waste production while requiring the operator to cleanup existing contamination. Since these requirements are being enforced, many operators do not have a clear under- standing, whether their existing operation will or could be required to adopt remedial plans to mitigate off-site contamination impacts. The following methods, using conventional and advanced geostatistical methods, provide a tool to make appropriate assessments whether existing or potential contaminant issues are present. BACKGROUND Generated solid wastes from mining operations are currently exempt from Solid Waste Disposal Act (SWDA) Sub- title C (RCRA), statutes and promulgated regulations, however, compliance with SWDA Subtitle D statutes and regulations is required. In order for the mining operator to be exempt from hazardous waste regulations, the operator must demonstrate that generated waste does not have hazardous waste characteristics. In many instances the operator will be able to use statistical tools and their existing data to determine whether their site could be a potential hazardous waste liability. METHODS The following statistical and geostatistical methods can be used to determine whether existing wastes could be a regulatory concern. The following presents a brief discussion of standard statistical methods and discusses, in greater detail, how advanced geostatistical tools can be used to define potential waste issues. The following will discuss how data can be screened, "Data Filtering and Reporting"; how data can be evaluated using "Conventional Statistics"; followed by a detailed discussion o f "Geostatistical and Estimation Techniques" and "Statistical Modeling". Data Filtering and Reporting Data filtering is the simplest, but potentially the most powerful statistical tool because data can be easily sorted to meet regulatory reporting requirements. Filtering includes unions and intersections of data such as date, maximum and minimum values of one or several variables. Using the data base presented in "Mine Waste Data Base Management Procedures", Robinson and Hagar, 1987, an example of a filter group is presented.

Jan 1, 1987

By David B. McWhorter, John D. Nelson

INTRODUCTION The quantity of seepage that will be released from a tailings impoundment depends not only on the characteristics of the seepage control system, but also on the properties of the foundation soil or rock beneath the impoundment and the nature of the groundwater in the area. The interaction between various elements of the seepage control system and the influence the various characteristics of the site and impoundment have on seepage are the subject of this paper. The results of analyses are presented herein to indicate the nature and magnitude of the effect that the various factors will have on seep¬age losses. Analyses were conducted for a uranium mill tailings impoundment located in an area characteristic of many found in the western United States or Canada. A typical seepage control system consists of placement of either a clay or synthetic liner beneath the impoundment. In some cases an underdrain system may be placed on top of the liner to collect drainage from the tailings. The parameters that were varied in the analyses included those pertaining to the liner, underdrains and foundation strata. In general, it is shown that the seepage losses will vary in a complex manner depending on the interaction of the elements of the site and the seepage control system. As may be expected, the liner and underdrain systems have the most pronounced effect on controlling seepage. This paper deals with the quantity of seepage released from an impoundment However, the impact that seepage losses from an impoundment will have on the surrounding environment will depend on the rate at which contaminants will enter the groundwater and the nature of the groundwater flow itself. Consequently, when considering these results with regard to environmental impact they must be interpreted along with considerations of geochemical factors. MECHANICS OF SEEPAGE The mechanics of seepage and methods of analysis that were used will be discussed briefly herein. For a more detailed discussion the reader is referred elsewhere (McWhorter and Nelson, 1978, 1979, 1980). A general column through the impoundment was considered to be as shown in Fig. 1.

Jan 1, 1980