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By Henning E. Soderberg

Yesterday, air pollution was somebody else's problem -- today, it is everybody's problem. The coal industry with thermal coal drying, is aware of their problem and the necessity of doing an acceptable job; however, there is much to be said as to how good a job is required and what performance limits should be set up. American Air Filter Company has been one of the pioneers in the solution of the thermal coal dryer dust problems, Because of high moisture content, products of combustion and occasional temperature surges, only wet collection has been considered as the practical approach. Our first installation goes back some 12 years with a total to date of 29 Individual wet collectors, each, fabricated of suitable corrosion-resistant material, at 14 operating plants. To eliminate a potential air pollution problem, a performance requirement of not more than approximately one-quarter (1/4) grains per cubic foot in the dust collector discharge was used. In nearly all installations, operating performance surpassed requirements, but discharge stacks were not entirely free of discoloration. However, plant nuisance and air pollution complaints were eliminated. This satisfactory performance was accomplished by medium priced wet dust collectors operating at a 4-6" W.G. pressure drop with cater drain requirements of about 1 gallon of drain water per 1000 cubic feet of air exhausted.

Jan 1, 1962

By L. Gutierrez, S. Gering, C. Calderon-Arteaga

"INTRODUCTION Drill and blast (DnB) represents the most important, and sometimes the most costly processes in a mine.. The cost of drilling and blasting operations greatly contributes to the “high cost trends of the overall mining operations” (Afum B. O. and Temeng V. A. 2015). The use of available information to improve the DnB processes can be the difference between a highly expensive process and an optimized one. Mining operations have access to several types of data sets and key information from a wide variety of different systems. This information is normally used to improve, evaluate and apply processes for drilling and blasting. This may include different types of data from the different stages of the process (before, during, and after the drilling and blasting operations), such as hole locations (planned and actual), penetration rates, drill operators, fragmentation (expected and resulting), explosive (design and usage), geology, vibration, and others. This information can be used on its own or combined for further analysis to reduce costs, improve safety, and evaluate results. Fortunately, due to advances in mining software, drill and blast engineers can exploit this data and create reports to evaluate results and improve the DnB process. However, as users start combining information from multiple datasets and establishing standard operating procedures for reporting this data across multiple sites, it becomes valuable to create auditable, automated, and sustainable processes for handling the information. In many cases the task of aggregating and standardizing the data formats has already been completed and is available to consumers via the Enterprise Data Warehouse (EDW). A data warehouse team extracts data from the source systems and transforms it so that it is meaningful for decision support (Barbara H. Wixom, Hugh J. Watson, 2007). Our initial implementation plan for the DnB solution included using data stored at the sites; however we learned early on in the process that much of the work for aggregating and supplying the required data was already completed. The goal for this case study is two-fold: to show how information can be used to make decisions and improve processes, highlighting the value of using an EDW for managing Drill&Blast information; and to discuss how technical challenges encountered during the implementations were resolved. This paper is targeted at users that want to better manage their DnB data or try to set up standardized workflows for using this information. This case study will discuss the process of implementing a DnB workflow at multiple sites within Freeport McMoRan Inc (FMI) using both data at the sites and information available using the EDW. The paper will begin with an overview of the project. The discussion will then describe how DnB processes were used to set up daily workflows in order to provide information for evaluating process and making decisions. The final section will discuss some of the technical challenges and how they were solved, as well as possible next steps for further improving the workflow."

Jan 1, 2017

By Robert C. Sutter

In 1958, it became obvious to some of us in the solution mining business that there were certain problems in connection with our sodium chloride brining operations which were industry- wide. These were the types of problems which, while they were important to the safe and economical operation of our salt brining operations, were not such that their solutions would give an individual company a great competitive advantage over his competitor; and since they involve the safe and efficient mining of a natural resource, it was obvious that the answers would, in any event, be shared industry-wide. Since we were dealing with underground solution mining and, consequently, unseen and remotely controlled operations, the problems are formidable and the solutions difficult. While all of us were doing work to improve our operations, none of us could justify the expenditures necessary for basic research in these areas. Consequently, the idea was conceived of research sponsored by many companies with the same problems. In 1960, 11 companies entered into a' formal agreement to jointly support research on a specific problem of sodium chloride solution mining. The project to be undertaken was the development of a method for measuring the size and extent of underground solution cavities in sedimentary salt beds. It was agreed that all research was to be performed by independent research organizations. A part-time consultant or administrator was retained to administer the research contracts and to provide technical advice.

Jan 1, 1966

By J. R. Gump

The term "rare earths" is used to designate a group of elements, Numbers 57-71 which are closely related chemically. They were called "earths" because their oxides resemble those of the alkaline earths, and the designation "rare" was originally applied because of their scarcity. Now many of these elements are known to exist in considerable quantities, and the term "Lanthanide" is applied to this group of elements, because of their similarities to lanthanum, the first element in the group. Many authorities insist on including yttrium, element Number 39, because of its extremely close association with the members of the group in nature and because of its similarity in chemical properties. It has been estimated that the combined rare earth group makes up about five-thousandth. of one percent of the Earth's crust, a higher percent than the common elements, lead, tin, zinc, arsenic, mercury, silver and gold. Cerium is by far the most abundant member comprising about half of the total amount. Yttrium, neodymium, and lanthanum are next in order; samarium, gadolinium, praseodymium, dysprosium, erbium, holmium, and ytterbium are increasingly scarce; while the elements lutetium, thulium, terbium, and europium are extremely rare. The rare earths as a group are metals, usually trivalent, forming basic oxides, and insoluble oxalates in dilute mineral acids. Their fluorides are also difficultly soluble; hence the rare earths or lanthanides may be separated, in general, from other elements by adding oxalic or hydrofluoric acid to a dilute mineral acid solution containing them. The most striking fact which characterizes these elements is the remarkable .similarity in both the physical and chemical properties of their compounds. Their main differences are in the solubilities of their salts and the basicity of their oxides, which vary between that of the alkaline earths and that of aluminum.

Jan 1, 1960

By James Douglas

For the past several years, inflation has placed increasing pressure on our economic system. The total effect of inflation is complex when combined with other factors which affect the economics of equipment. A mathematical model is described herein which can be programmed on a computer to determine the effect of inflation on economic life and profits after taxes. The computer output results in graphic plots which clearly show the relation of various percentages of inflation to life and profits. Inflation has become a common topic of conversation in the recent past. What is it and how can it be measured? What effect does increased inflation have on equipment policy? Research now in progress at the Construction Institute at Stanford University is beginning to unravel some of the mystery of inflation. As a start, let us answer the first question by defining the word inflation. The dictionary says that inflation is "an increase in the volume of money and credit relative to available goods resulting in a substantial and continuing rise in the general price level. It appears, in fact, that we are in an inflationary spiral which is "a continuous rise in prices that is sustained by the tendency of wage increases and cost increases to act on each other." 3 Inflation behaves just like compound interest. It takes more dollars of future years to buy an equal amount of a given commodity, be it a material or a service. Let us assume an annual inflation rate of 5 percent. Assume that 1Associate Professor of Civil Engineering, Stanford University, Stanford, California. 2Webster's Seventh New Collegiate Dictionary, Springfield, Mass., G. and C. Merriam Co., 1969. 3Ibid.

Jan 1, 1972

By R. E. Coleman

Infrared spectroscopy, employing the internal reflection method in conjunction with solvent extraction techniques, was used to study surface reactions between aqueous potassium ethyl xanthate and both sphalerite and precipitated zinc sulfide each activated with aqueous copper sulfate. It was determined that reactions occurring on the sphalerite and zinc sulfide surfaces produce the reaction products ethyl dixanthogen and cuprous ethyl xanthate, some of which are ad¬sorbed on the mineral surfaces. According to infrared spectra showing the reaction to form these compounds, the ratio of cuprous ethyl xanthate to ethyl dixanthogen adsorbed is directly related to pH of the flotation solution.

Jan 1, 1967

By Ian M. Loomis, Keith G. Wallace

The Waste Isolation Pilot Plant (WIPP) is a U.S. Department of Energy research and development facility designed to demonstrate the permanent, safe disposal of U.S. defense-generated transuranic waste. The waste storage horizon is 655 m (2150 ft) below surface in bedded salt. To date the WIPP project has not emplaced any waste. There are three intake shafts used to supply air to the underground. All air is exhausted though a single return shaft. The total design airflow during normal operations is 200 m3/s (424,000 cfm). The ventilation system is designed to provide separate air splits to construction, experimental, and storage activities. Separation is achieved by isolating the storage circuit from the construction or experimental circuits with bulkheads. Any air leakage must be towards the storage area of the facility. Field studies have shown that the pressure differential necessary to maintain the correct leakage direction is susceptible to the effects of natural ventilation; therefore, extensive studies and analyses have been conducted to quantity the natural ventilation effects on the WIPP underground airflow system. A component of this work is a monitoring system designed to measure the air properties necessary for calculation of the natural ventilation pressure (NVP). This monitoring system consists of measuring dry bulb temperature, relative humidity, and barometric pressure at strategic locations on surface and underground. The psychrometric parameters of the air are measured every fifteen minutes. From these data, trends can be determined showing the impact of NVP on the ventilation system during diurnal variations in surface climate. Both summer and winter conditions have been studied. To the author's knowledge this is the first reported instance of automatic and continuous production of time and temperature variant NVPs. This paper describes the results of the initial monitoring study. INTRODUCTION The ventilation system at the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico, is designed to perform two distinct functions. First, it supports normal mine ventilation requirements complying with all state and federal mine regulations. Second, the system is designed to prevent an uncontrolled release of radioactive contaminants from the storage and transportation areas of the facility. Although a nuclear radiation release in the facility is considered unlikely, many special features are implemented in the ventilation system to prevent the possible spread of contamination. The facility is constructed with the waste transportation and storage areas separated from the mining and non-radioactive experimental areas. The ventilation system is designed such that air leakage is from the mining and experimental areas to the storage areas. Furthermore, radiation detectors are located throughout the storage and waste transportation areas underground and an exhaust filtration building is installed on surface to prevent the possible release of radiation to the environment. For over two years the underground ventilation system has been rigorously tested and balanced. It was during this period that the adverse effects of NVP were noticed and subsequently quantified. From extensive field studies and computer models, several mitigating features were designed and constructed and special operational procedures were implemented to control the impacts of NVP. To quantify more accurately the NVP at the WIPP, a continuous monitoring system was installed. This monitoring system consists of measuring dry bulb temperature, relative humidity, and barometric pressure every fifteen minutes at strategic locations on surface and underground. From this psychrometric data, the NVP is calculated. Fan operating pressures and flows and strategic differential pressures are recorded from the site Continuous Monitoring System (CMS). The monitoring system provides a means of evaluating how the ventilation system behaves in regard to climatic conditions and to judge the efficacy of the mitigating features and operational procedures. To the author's knowledge, continuous calculation of NVP as a function of time and surface temperature has not been previously reported. Overview of the Waste Isolation Pilot Plant The U.S. Department of Energy determined that the plastic nature of bedded salt may provide the best solution to isolate transuranic (TRU) waste from the biosphere. Initial evaluations at the WIPP site began in 1974. In 1979, the United States Congress enacted Public Law 96-164 for the construction and development of the WIPP project. The mission of the WIPP is to demonstrate the safe, long-term disposal of TRU waste generated by the national defense programs of the United States. TRU waste is classified as a low to medium level waste. The waste is stored in drums and does not produce significant heat (not greater than 1 W per drum). The WIPP site is located approximately 47 km (29 miles) east of Carlsbad, New Mexico in the Chihuahuan Desert. The repository is located in the 630 m (2000 ft) thick Salado Formation. This Permian Basin salt deposit is about 225 million years old and appears to have been minimally disturbed by earthquake, faulting, and ground water activity since it was deposited. The underground facility is 660 m

Jan 1, 1993

By Ulrich Maidl

The use of EPB shields in the so-called mixed face conditions has set new demands to man and machine in EPB shield tunneling. EPB shields were initially conceived to drive in the pressurized closed mode in soft ground, whereas hard rock TBMs were designed to work in the unpressurized open mode. The present use of EPB shields in hard rock and mixed face conditions requires the combination of both technologies by finding best compromise solutions. This paper deals firstly with the geotechnical and mechanical interactions between machine and ground. Further on the critical points such as tool wear and tool replacement are exposed, together with a proposal of best solutions.

Jan 1, 2003

By G. R. Struble, J. R. Marks, A. B. Brown

The center of mining at the Homestake gold mine in Lead, SD, is moving deeper every year. As a result, it has become necessary to upgrade the ventilation system. This paper describes the first phase of a scheduled two-phase upgrade - installation of a 2.2-MW (3000-hp) centrifugal fan. The higher pressure fan is required to route larger airflows into the deeper production levels. Selection of the fan began by specifying the necessary operating point to provide these larger airflows. Special site work had to be done on the surface to accommodate the new fan structure as well as underground to reroute airflows.

Jan 1, 1987

By Stanley R. Riggs

Extensive phosphate resources occur within the Miocene Hawthorn and Pungo River Formations which have not been considered in the past since they were poorly known and were not available to conventional mining. These resources include 1) deep phosphates that occur below 75 meters of overburden within major sediment basins throughout the southeastern coastal plain, and 2) offshore phosphates that occur on the continental shelf and within the U.S. Exclusive Economic Zone (EEZ). The future potential of these two vast resources will be realized with development of new mining technologies such as hydraulic slurry mining and integrated with advanced technolgy already being utilized in the offshore petroleum industry.

Jan 1, 1986

By A. I. Makhin, S. M. Sablukov, V. K. Sobolev, V. A. Larchenko, V. S. Shchukin

The kimberlites of northern Europe are related with a large crustal block having a northwest-southeast orientation. Kimberlites penetrate the Archean formations of crystalline basement, Late Proterozoic rocks, which are overlapped by Middle Carboniferous and younger deposits. The kimberlites bodies include pipes, dikes and sills of Upper Devonian age. Within the region, rocks of two magmatic series form diamond-bearing kimberlites. Aluminum rocks form a new type of diamond-bearing rock that is not found in other diamond provinces. Kimberlites of this region are characterized by highly developed deuteric alterations, a low content of associate minerals, the presence of two diamond generations and an increased content of jewelry-grade diamonds.

Jan 1, 1997

By Allen Pratt, Guy Deschênes, Mike Fulton, Hai Guo

Calaverite is a gold telluride species, with the composition, AuTe2. Calaverite is usually characterized by an exceedingly slow dissolution rate in a cyanide solution. Cyanidation of a slurry containing synthetic calaverite (P90 of 10 microns) was studied to determine the leaching kinetics and surface reactions. Alkalinity, dissolved oxygen, lead nitrate and sulphide minerals (pyrite and chalcopyrite) were among the parameters evaluated. The reaction products at the surface of calaverite were documented using X-ray photoelectron spectroscopy. High lime concentration with lead nitrate and injection of oxygen produced the fastest leaching rates. New gold leaching mechanisms were identified which appeared to be related to the parameters selected.

Jan 1, 2005

By P. M. Brown

The Bureau of Mines, U. S. Department of the Interior, has developed a method of dewatering clay slurries based on flocculation by high-molecular-weight polymers and water removal from the formed flocs using a trommel or hydrosieve. The exchange ion on the clays affects their dewaterability. Metal ions in solution and on the exchange sites of smectite clays are known to act as Lewis acids. Recent work has determined that these ions can be titrated with high-molecular-weight polymers. The relative acidity of the exchange ion and the basicity of the polymer determined by the new method give insight into the dewatering mechanism.

Jan 1, 1988

By Arun Patel, Diane Hirsch, Pamela Moran

The Metropolitan Washington Airports Authority (Authority) has undertaken a tremendous expansion of Washington Dulles International Airport in Fairfax, Virginia, including upgrading passenger transportation between concourses. The first stage of this expansion envisioned a shallow cut-and-cover pedestrian tunnel between the Main Terminal and Concourse B with associated vertical circulation structures. At the beginning of the design contract, the Authority’s consulting team of Earth Tech, formerly Kaiser Engineers, and the Dr. G. Sauer Corporation compared the cost and disruption of constructing the tunnel as a cut-and-cover structure to mining the tunnel using the New Austrian Tunneling Method (NATM). Upon review, the Authority endorsed the latter method.

Jan 1, 2003

By J. Harrison Daniel

Increasing concerns of industrial hygiene and worker health issues and resulting regulatory actions, coupled with continuing advances in mining systems, are placing new burdens on the industry and Federal Government; particularly, mine ventilation departments. More encompassing worker health programs are required to respond to Federal promulgation of regulations and to keep abreast of techno- logical advances in the mining industry. The relationship between the mining industry and Federal agencies involved in rulemaking is presented, along with the rationale of an Industrial Hygiene Management Plan. This plan or strategy focuses on developing partnerships and collaborative research groups to address the controversial health issues facing not only the mining workforce, but our society.

Jan 1, 1993

By Chris Chmura, Ketut Karmawan, Ian J. Duckworth

P.T. Freeport Indonesia operates a mining complex located in the highlands of West Papua, Indonesia. Present production from PTFI’s DOZ Underground Block Cave Mine is approximately 40 thousand tonnes per day (ktpd). This paper describes the design process and recommended ventilation infrastructure necessary to expand the DOZ Mine reserves and to increase sustained daily production above 50 ktpd. The enlarged footprint will feature longer production panels of up to 650 m in length, more active draw points, a second large gyratory crusher, and additional men and mobile equipment. The increased ventilation capacity will be achieved through the development of new, dedicated ventilation drifts, and primary Underground exhaust fans.

Jan 1, 2005

By D. A. Stanley, B. J. Scheiner, P. M. Brown

The Bureau of Mines (USBM), US Department of the Interior, has developed a method of dewatering clay slurries based on flocculation by high-molecular-weight polymers and water removal from the formed flocs using a trommel or hydrosieve. The exchange ion on the clays affects their dewaterability. Metal ions in solution and on the exchange sites of smectite clays are known to act as Lewis acids. Recent work has determined that these ions can be titrated with high-molecular-weight polymers. The relative acidity of the exchange ion and the basicity of the polymer determined by the new method give insight into the dewatering mechanism.

Jan 1, 1990

By J. A. Lombardi

"EXECUTIVE SUMMARY The use of membranes for the treatment of Acid-Mine-Drainage (AMD) water has been a 35 year mining industry quest that has only recently produced commercial scale Zero-Liquid-Discharge (ZLD) plants. The process of development of the membrane treatment of AMD has been defined by the water treatment industry’s efforts to control gypsum scaling of the membranes, an artifact of the concentration of calcium and sulfate ions on the concentrate or “brine” side of the membranes. Improved anti-scalants, changes to membrane surface geometry and a lowered permeate flux rate were all part of solving the calcium sulfate (gypsum) scale formation problem. Whether used singly or as part of a multi-stage membrane treatment process, the production of “left over” membrane concentrate or brine, in any volume large or small, was a second barrier to adoption of the method by the mining industry. The two identified “final brine” treatments were a) solar evaporation ponds and b) mechanical evaporators. Brine disposal by solar means is typically site limited to flat terrains or high net evaporation locations. Mechanical evaporation-crystallization is applicable at all sites but, typically, at onerously high ownership and operating costs. Miwatek, a South African water treatment start-up, has entered the mining AMD ZLD marketplace with two new, pilot-scale tested, processes, both of which are predicated on the innovative treatment of a reasonably concentrated AMD and neither of which produces a final brine that requires disposal. In the Miwatek Brine Treatment, MBT, method the membrane brine is caustic pH adjusted and de-calcified precedent to passage through a second membrane plant. The caustic is generated on-site by a lime treatment of the second-membrane concentrate. The first- and second-stage permeates are blended for discharge. The process usually yields no “final brine” for disposal. In the Miwatek Ettringite Treatment, MET, method a low pH first-stage membrane brine is lime treated in two or three steps in the presence of aluminum in a way that metal hydroxide and calcium sulfate solids are formed and purged from the system. Sufficient aluminum is often present in the feed water to, with judicious recycling, enable operation of the lime-aluminum treatment without the purchase of outside aluminum reagent. The first-stage membrane permeate is blended with the lime-aluminum treated membrane concentrate for discharge. The indications are that the method can comfortably meet the low 250 -500 ppm SO4 discharge water quality standards that have most recently been proposed in South America. The process yields no “final brine” that requires disposal. Projected own-operate costs for the MBT and MET systems are less than the estimated costs for all identified alternative treatments."

Jan 1, 2015

By J. W. Craven, M. Katom, K. M. McCaffery

At Ok Tedi, ore type and SAG feed size distribution vary widely and frequently. This makes control of the SAG mills by application of the power/pressure relationship difficult. Power logic has traditionally been conservative due to power spikes associated with rapid size-distribution changes. A new expert system was installed in early 2000. The system incorporates multiple state fuzzy logic to deal with frequent and radical ore type and size variations, along with monitoring of motor temperatures. A short-term power spike no longer warrants immediate radical action. This has resulted in increased mill throughput and improved circuit stability. Key words: SAG mills, Mill control, Fuzzy logic

Jan 1, 2003

By Daniel Tempelis, Tom Freeman, Eric Fordham, John Shamma, Steven Duke

The Arrowhead Tunnels in southern California are being completed by MWD under stringent groundwater in?ow limits established by the U.S. Forest Service. Pre-excavation grouting, new TBMs and a bolted, gasketed, pre-cast concrete segment initial lining are employed to control water in?ows. The effectiveness of prescribed water control measures was analyzed using conservative assumptions with the analytical techniques described by Goodman (1964), Heuer (1995), and numerical modeling. Analyses results suggest groundwater in?ows to the tunnels can be maintained well below the limits with aggressive pre-excavation grouting balanced against a reasonable rate of advance and quality erection of the initial lining system.

Jan 1, 2003