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By Emily Sarver, Cigdem Keles, Jonathan Gonzalez

The study re-examines respirable coal mine dust samples using scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). It finds that SEM tends to overpredict the abundance of dust from rock strata and underpredict coal content, possibly due to coal-mineral microagglomerates (MAGs). The findings suggest that MAGs could be valuable in improving dust controls in mines.

Feb 10, 2022

By Otis M. Clarke

The purpose of geochemical research in the Alabama copper belt is to re-evaluate geochemical prospecting methods as related to igneous and metamorphic rocks in a humid climate. It is also a correlation of laboratory research on copper mineral solubility with geochemical anomalies over known mineral deposits. Geochemical prospecting in warm humid climates involves different problems and conditions than geochemical prospecting in semiarid areas. Stems and others (1972) reported soil surveys in a humid tropical environment in Bahia, Brazil, were not effective in outlining areas of copper mineralization. Clarke (1971) reported false anomalies in lateritic soils in Alabama over mafic rocks. Bjorklund (1971) reported biogeochemical sampling in Finland was ineffective in detailed work outlining potential mineralized areas, although it may serve to indicate regional areas of high mineral potential. During this investigation, water, stream sediments, residual soil, and organic matter, mainly twigs, were collected from three known copper-mineralized areas. Samples were selected so as to cross mineralized outcrops and results were correlated with copper stability charts as reported by Silman (1958) and Schmitt (1962). The geochemical research performed in Alabama should be applicable to other humid areas. Geologic, Climatic, and Pedologic Setting The area of investigation is in the southern end of the Appalachian eugosyncline in eastern Alabama. It includes the Hatchet Creek prospect, Pyriton mining district, and Stone Hill copper mine. The copper mineralization is in calcium-rich metasediments that lie along the western flank of a high rank metamorphic belt. All three deposits are in the uplands of the Ashland Plateau section of the Piedmont physiographic province. The Hatchet Creek copper prospect (Clarke, 1963; 1971) consists of three mineralized areas that contain pyrrhotite, pyrite, and chalcopyrite in small crisscrossing veinlets.

Jan 1, 1972

By Stefan Medel

As a pioneer Herrenknecht started in 2018 to automate the production of tunnel lining segments. Since then, many automation processes became state of the art. Robots cleaning and oiling the moulds, hydraulic units opening and closing them fully independently. Artificial Intelligence (AI) controls the works and ensures the quality requirements. Data management has become a massive tool from a simple data collector towards a control and optimization tool. Sensors controlling concrete maturity and supporting the precast team to optimize the concrete mix. These state of the art and new innovations will be presented in this paper.

Jun 23, 2024

By Hal McVey

"Philosophy" addresses the definition and assigning of importance to the marketing of by-products. Two examples, one in metals and the other in industrial minerals, explore prime product to by-product relationships. Relative revenues from all products illustrate the importance of by-products to economic feasibility. "Mechanics" takes a broad view of the types of marketing organizations that are applicable to individual circumstances in the marketplace. In-house marketing as well as agents, merchants and trading companies are outlined and discussed. Philosophy Definition Of Terms Philosophy Definition Of Terms The definition of terns for a paper such as this is generally a necessary but not-very-interesting exercise. However, in simply trying to clearly define the term "by-product" some interesting relationships between products arise and the line of demarcation between "product" and "by-product" often becomes obscure. The search for that distinction represents the philosophy portion of the title. A couple of definitions of philosophy can even help to set the tone for what follows. According to Webster, philosophy is : 1 Pursuit of wisdom. 2. A search for a general understanding of values and reality.

Jan 1, 1983

By Hojong Kim, Isehaq Al-Nafai, Kwadwo Osseo-Asare

The standard Gibbs free energy of formation (ΔGo f, 298) of bastnasite, (Ce, La, Nd, Pr)FCO3, was estimated using four different methods. The obtained average values were − 1589.5 kJ/mol for CeFCO3, − 1599.5 kJ/mol for LaFCO3, − 1589.1 kJ/mol for NdFCO3, and − 1595.4 kJ/mol for PrFCO3. The value for cerium bastnasite, CeFCO3, was used to construct a potential vs. pH (Eh-pH) diagram to investigate the stability relations of cerium bastnasite. The diagram shows that CeFCO3 is stable in neutral to basic conditions (pH ~ 6.5–11).

By Derek J. McCracken, William G. Holroyd

Emery is a rock that at one time held a large share of the abrasives market. The introduction of synthetic abrasives, however has forced it to settle for only certain niches in the marketplace. This loss of market share is due mainly to the higher amounts of impurities and weaker internal structure that naturally occurring minerals have compared to manmade materials. The use of rocks and minerals as abrasives dates back to early man, who used flint, quartz, and other natural materials to fabricate various tools. During the 19th century, with the Industrial Revolution imminent, the character of the abrasives industry was changed forever as synthetics were introduced. Frank B. Norton is credited with producing the first manmade abrasive when, in 1855, he manufactured a vitrified grinding wheel using emery grit and clay. Before Norton's accomplishment emery had been the only commercially available abrasive. The latter part of the 20th century has seen synthetics capture an increasing share of the abrasives market from natural materials. The term emery is believed to have been derived from the words emeri (French), smeriglio (Italian), and smiris (Greek). The term corundum, for the principal mineral of emery, seems to have originated from kauruntaka, the Indian name for the mineral. GEOLOGY Emery is a gray to black, granular rock comprised of various minerals including corundum (A1,0,), an iron-bearing mineral (usually magnetite-Fe,O,, hematite-Fe,O,, or hercynite- FeAI,O,), and several trace impurities such as mullite, titania, silica, and magnesia. The hardness of emery normally ranges between 7 and 9 on the Mohs scale, depending on its mineral com- position and level of impurities. Corundum, the hardest mineral in emery, typically has a hardness of 9. The specific gravity of emery ranges from 3.2 to 4.5, also depending on mineral composition and purity. The crystallography of each mineral contained in emery differs somewhat. Corundum exhibits an hexagonal crystal structure, whereas magnetite forms within the isometric system, frequently as octahedral crystals. Hercynite, an iron spinel, is also isometric. Hematite has an hexagonal structure but often is found as botryoidal and reniform masses. Principal deposits of commerical emery are found in the United States, Turkey, and Greece. In the United States two emery producers in the Westchester County-Peekskill area and one in the Cortlandt County area of New York closed their mines in the late 1980s. Commercial production in the United States now comes only from the western Cascade Range in Oregon. The emery in New York has a typical A1,0, content of 41.5%. Most of the rock is not true emery because it contains a mixture of spinel and magnetite but very little corundum. The deposits are of Late Ordovician-Early Silurian age and consist of veins in which emery is mixed with olivine, pyroxene, and hornblende. The veins evidently were formed by contact metamorphism and are surrounded by Precambrian schists that contain mica, sillimanite, cordierite, garnet, and quartz. The deposits in Oregon were formed during Miocene time by the contact metamorphism of ferrunginous bauxite by intrusive lamprophyric dikes and plugs. Emery is found in thin layers bordering these tabular dikes, which are usually oriented perpendicular to bedding, and in "surficial placer deposits. The emery deposits in Turkey occur as small, massive, lens- shaped bodies and as surficial placers. They are believed to have formed during Permian and Triassic times. In Greece the principal site of emery production is at Cape Emeri on the Island of Naxos. These deposits consist of lenticular masses of emery surrounded by marble. They originated during Mesozoic time, evidently by metasomatic replacement. Smaller deposits on several other Aegean islands were formed by the metamorphism of bauxite or other alumina-rich materials.

Jan 1, 1994

By G. Bylapudi, A. Spearing, J. Weber, K. Mondal

U.S. National Institute for Occupational Safety and Health (NIOSH) reports state that about 100 million rock anchors are installed annually in U.S. coal mines (Tadolini et al., 2006), and rock-related safety remains an issue. The majority of these coal mines have conditions that make corrosion probable in the longer term. Despite this, very little research has been performed to analyze corrosion and its effects on rock anchors in coal mines. To further evaluate the effects of corrosive conditions in coal mines on rock anchors, three different experiments were conducted during an initial Illinois Clean Coal Institute (ICCI)-funded project from 2008-2009. The results of these experiments were further studied, with additional tests, in the extended ICCI-funded project during 2011-2012. The experiments were destructive testing, electrochemical testing (potentiodynamic polarization tests) and open circuit potential (OCP) testing, conducted in order to study corrosion in environments similar to those found in Illinois coal mines with a focus on major rock anchor types typically installed underground. Destructive test results showed highest reduction in peak strength at higher pH and temperature. From the destructive test results, epoxy-coated and galvanized anchors were observed to be better when compared to uncoated. Electrochemical testing was performed to find the corrosion potential and corrosion rates of ASTM A615 steel grades 40, 60 and 75 in four different solutions of varying sulfur content at ambient temperature. The effect of temperature and pH levels on corrosion potential and corrosion rates of steel grades were also evaluated with additional electrochemical testing, where an increase in temperature with all other constant conditions caused a significant increase in the corrosion penetration rate. OCP data indicated higher corrosion potential values (-mV) for rock anchors in wet areas, when compared to those from the dry areas. OCP test results of the rock anchors from the laboratory corrosion chambers were similar to those measured in the sampled coal mines.

Jan 1, 2013

By D. A. Rice

In pelletizing magnetic iron ore concentrates, about 6 to 18 lb of bentonite binder are added per ton of concentrate during balling to give green and dry strengths to the unfired pellets. The dry bentonite is mixed into the filtercake following the magnetic concentration circuit of the plant. The filtercake contains about 10% moisture, and the water may be of highly variable composition, depending on the particular concentration circuit, its source, and the ore being treated. A knowledge of the parameters that influence the balling operation is essential for optimal efficiency in producing balls strong enough to survive the treatment during transportation from the balling device to the furnace and during the firing operation. Furthermore, very weak unfired pellets probably contribute to high dust losses and poor furnace control. The factors that determine the strength of unfired pellets have received considerable study (1,2,3,4). Tigerschiold and Ilmoni(l) pointed out the significance of the surface area of the particles being pelletized. Merklin and Childs(2) reported on the effect of material size consist, chemical additives such as soda ash, lime, balling time, ball size, and the moisture content of green balls. Iwasaki and Zetterstrom(3) examined the detrimental effects of fatty acids on the pelletizing process. Stone(4) correlated the zeta potential of bentonites with the strength of unfired pellets. He found that, in general, a high negative charge on the bentonite is conducive to good balling. Although studies of pelletizing in the iron ore industry deal with a complex multicomponent system consisting mainly of the iron mineral, bentonite, and water, the last of these has received little attention, particularly with regard to the possible effects of mill water chemistry on the pelletizing process and the strength of unfired pellets. It is widely known that the composition of mill process water is an important variable in unit operations such as flotation, thickening, and filtering and that impure water can lead to poor metallurgical results. The results of the present study indicate that the chemistry of the mill water may be an important variable in the balling operation as well. Knowledge about this variable should contribute to lowering bentonite and oil consumption and to improving furnace performance. Such knowledge can also assist those who use balling in evaluating commercial bentonites for plant use as well as those investigating balling from a more fundamental point of view In this study we have examined 1) the effects of replacing mill process water in the magnetic concentrate filtercake with pure water, and 2) the effects of several chemical impurities that are commonly found in mill process waters upon the strength of unfired pellets. The results are interpreted in terms of the zeta potential of the bentonite and magnetite particles. The data lend support to a suggested mechanism whereby the electrostatic attraction of oppositely charged particle surfaces causes bentonite-bentonite and magnetite-bentonite bonding. This mechanism would also explain why several chemical additives e.g., sodium carbonates and phosphates, have such marked effects on increasing the strength of unfired pellets.

Jan 1, 1971

By S. S. Peng

A well designed mining plan is one which minimizes the cost and the mining induced problems and maximizes the recovery of the coal reserve. In order to minimize the negative effects on surface structures caused by ground subsidence process due to underground mining activities, two kinds of practices are commonly employed by the mine operators. One is the support techniques which leaves an area of coal un-mined or partially mined beneath the structure to be supported. The other is the protection techniques which protect the structure when it is subsiding with ground taking advantage of the ground subsidence process (Luo et al., 1992). In designing the supporting techniques, the only currently available method in the U.S. is the one stated in the Pennsylvania Underground Coal Mining Rules (1985). However; The size of the support area designed by this method will be excessively large resulting in wasteful use of coal reserve when the overburden depth is more than 350 ft. A more scientific method is proposed in this paper for de-signing the support area. This method is based on a large amount of subsidence data collected throughout a number of major U.S. coal fields and the authors' experience with monitoring and protecting surface structures undermined by longwall panels. It considers the critical deformation in-dices that a structure can tolerate, and depth and height of underground extraction. The support area designed by this new method will not only assure the safety of the structure to be supported but also maximize the extraction of the coal reserve.

Jan 1, 1993

By W. Nazarewicz

The introduction of continuous papermaking in the early 1800's was the beginning of the industry as we know it today. Since that time, the majority of the paper produced has employed an acid process. However, in the mid 1960?s, European producers began a transition to an alkaline papermaking process. Early European mill conversions to alkaline papermaking begun in the 601s, accelerated during the 1970's influenced by the dramatically higher cost for OPEC energy as well as the high cost of fiber and imported filler clay.

Jan 1, 1986

By E. H. Boswell

The Mississippi embayment east of the Mississippi River is part of a vast geologic and hydrologic province. The abundance of water available is largely responsible for the agricultural history of the area and is perhaps the key factor in the rapidly accelerating trend toward industrialization. The multiple artesian aquifer systems that underlie the region, and the alluvial aquifer along the Mississippi River are virtually undeveloped sources of fresh water in that they are yielding only a fraction of the water available. The potential yield of the 12 aquifer systems is estimated to be about 25,000 mgd (million gallons per day), of which only about 600 mgd is presently being withdrawn. The amount of water in storage in these systems is about 1,600 trillion gallons. Ground water having a dissolved-solids content of less than 500 parts per million is generally available at depths of less than 1,000 feet, and water having a dissolved-solids content of less than 1,000 parts per million is available in some places to depths of more than 3,000 feet. Iron is the most common troublesome chemical constituent in the ground water. Water in varying amounts is also available from streams within the region. The amount of water which originates within the region and which leaves it as streamflow during a year averages about 50 million acre-feet (about 45,000 mgd). An additional 375 million acre-feet (about 340,000 mgd) leaves the region as streamflow during an average year, this amount having originated outside of the region. Some streams have considerable flow during periods of no precipitation, and the water during these periods generally has a low dissolved-solids content.

Jan 1, 1966

By Zhen-xing Diao, Feng Zhao, Ya-dong Xue

"Two important aspects of excavation performance of TBM are advance rate and cutter replacement/ring consumption, which is closed to the cost and construction duration of the project. To achieve this, a database of TBM parameters and the geological-geotechnical conditions during the excavation of Yinhanjiwei was compiled and analyzed. Relationships between different geological and TBM operational parameters were investigated. Results of analyzes show that there are qualitative correlation between Field Penetration Index (FPI) and rock geological parameters. And strong relationships between FPI and operational parameters are suggested. In this study, the cutter replacement and ring consumption were analyzed using statistical method for preliminary estimation in similar conditions. 1. ITRODUCTION Hard rock TBM is widely used in tunneling project nowadays because of its advantages to conventional drilling and blasting, especially in long tunnels. The biggest advantage is its high advance rate. However, rock conditions of tunnels are complicated. So TBM performance becomes a primary topic in tunneling engineering, which includes of rate of penetration, utilization, daily advancement, cutter consumption and so on. Many prediction models have been developed to estimate the TBM performance in the project planning phase. The most widely accepted and used models around the world are semi theoretical CSM model (Rostami and Ozdemir, 1993; Rostami, 1997) and the empirical NTNU model (Blindheim, 1979, Bruland, 1998).With increasing uses of TBMs in different ground conditions, an increasing number of researchers have developed new models in order to predict the performance of TBM more accurately in similar geological conditions.(Gong and Zhao, 2009; Hassanpour et al.,2009, 2010, 2011, 2014; Delisio et al., 2013; Delisio and Zhao, 2014)"

Jan 1, 2016

By Yinan Zhang, Y. Luo

Most of the reported coal spontaneous combustion events occur in surface and underground mines where low rank coals (i.e., subbituminous and lower for this particular studies) are extracted indicating their high propensities for spontaneous combustion. Low rank coals have high moisture content (15 to 45%) and are capable of absorbing more moisture in dried condition. However, it is hard to induce the initial stage of self-heating process for the low rank coal using the current laboratory R70 testing method — a method widely used in the coal industry. Like a sponge, dry low rank coals can absorb water vapor in the air while the heat contained in the moist air is transferred to coal and served as the required activation energy to initiate the coal self-heating process. In order to prove this theorem and quantify the effects, the R70 adiabatic oxidation testing method has been improved to introduce a controlled moist flow into the coal reaction vessel. Tests using the new method and its setup on low rank coals showed that the initial self-heating process of coal sample can be greatly accelerated by the added water vapor — impossible with the regular R70 method. Once the self-heating is sustained, the removal of air moisture can further accelerate the process.

Sep 17, 2021

By L. Alagha, M. Khodakarami

"This work focuses on the extraction of rare earth metals (REE) from aqueous solutions using stimuli-responsive polymers. Various parameters affecting the adsorption capacity of the polymer, including pH, polymer concentration and REE concentration were studied. The interfacial behavior of REE in aqueous phase before and after polymer addition and the mechanism of the formation of metal-polymer complexes and their properties were investigated using UV/VIS spectroscopy. Results obtained would help to test the feasibility of employing stimuli responsive polymers in pre-concentration of rare earth elements associated with other elements in mineral aqueous streams prior to solvent extraction. The pre-concentration step would reduce the amount of organic solvents used for extraction and striping compared to conventional extraction processes. INTRODUCTION Rare earth elements (REEs) have become the foundation for several technologies and have been used extensively in many industries such as modern electronics, green energy, health care and transportation and defense [1-4]. As these industry sectors are growing, the global consumption of REEs is going to increase dramatically. The current global REEs demand is estimated to be 105,000 tons of rare earth oxides per annum with an expected annual growth of 5.6% [5-6]. Rare earth elements are produced from different sources (primary and secondary). China is considered as the largest producer of REE in the world, providing about 90% of the world’s mine production while the United States is second with 4% of the mine production [7]. High global demand for rare earth materials results in shortage of such materials in the near future. It should be considered that the term ‘‘rare’’ earth is not an accurate term, since they are abundant in some extent in the Earth’s crust, but are typically finely dispersed. Thus, nowadays looking for more efficient and cheaper methods for extraction, separation and purification of low concentrated REE ores and exploring secondary sources are essential. Rare earth materials are found in raw condition and require treatment that involves several processes, which can consume money and time. Recent improvements in extraction and recycling technology have made the extraction of rare earth elements from rare earth sources more feasible in terms of cost and time [8-10]. Physical and pyrometallurgical methods require high-energy and thus high costs. Moreover, due to environmental problems, environmental protection systems are required, and they are not as adaptable as chemical processes [11, 12]."

Jan 1, 2016

By Oscar Cabello, Luis Mendieta, Maribel Guzman

Mineral flotation processes generate large volumes of tailings, which must be disposed of efficiently and safely. In addition to dry stack disposal, the possibility of reusing these tailings as aggregates in shotcrete is an interesting alternative. Tailings samples from a mining operation in southern Peru were characterized by granulometric analysis, X-ray diffraction and Scanning Electron Microscopy. Concrete samples were obtained with different tailings formulations. The samples were subsequently subjected to geomechanical testing. The results showed that replacing 20% to 30% of the tailings with aggregates in shotcrete production achieved compressive strengths exceeding 30 MPa after 28 days of curing, with an energy absorption capacity of 500 joules. Results show that this shotcrete can be used in the support stage of the mining cycle in underground mining.

Feb 22, 2026

By John W. Leonard

The typical tunnel boring machine in use on today's tunnel project uses 15'2-inch diameter cutters at a nominal load of 45 kips per cutter. The cutterhead rotates at a speed of 120 over D revolutions per minute where D is the cutterhead diameter in feet. The typical machine operates about 50 percent of the time. Delivery of a new machine takes 12 to 15 months. The TBM is a specialized tool and not applicable to all jobs. There is a range of job conditions that limit the economic use of a TBM. The machine should provide a thrust per cutter at least twice the compressive strength of rock in psi and up to three times the rock strength is required if in "granitic rocks." The rock strength in psi must be at least three times the cover above the tunnel in feet or the machine may stick. For example, 2,500 feet of cover requires at least 7,500 psi rock to avoid problems. When the RQD's over a significant distance of the project are less than 50, the TBM becomes support-bound. When a large percentage of the time is spent waiting while the ground is supported, the TBM cannot perform well (See Figure 1). This problem increased inversely with tunnel diameter. We are finding that increasing the RPM's does not significantly increase progress. The increased RPM results in a substantial decrease in cutter penetration. The explanation for this decrease appears to be vibration, cutterhead drag, or lack of stiffness in the cutterhead (See Figure 2).

Jan 1, 1981

By Fred Delabbio, Sverker Hartwig

As openpit copper operations transition from surface mines to underground, the speed of underground infrastructure construction prior to production is critical for maximizing the value of the project. Typically, the preferred underground bulk mining method is block caving. In preparation for future underground projects, Rio Tinto made the strategic decision to invest in a step-change program that would develop system solutions to reduce the construction time of block caves. The program focused on improving safety and doubling or more the construction speed of both vertical shafts and horizontal infrastructure compared to existing drill-and-blast rates. After an extensive selection process, Rio Tinto selected the Atlas Copco mobile miner machine as one of the concepts to proceed with for construction of horizontal infrastructure for access and footprint. In addition to un-derground drilling and hauling equipment, Atlas Copco?s Robbins mobile miner concept (a previous attempt at horizontal mechanical excavation) completed trials at Mount Isa, Pasminco and Taisei. Rio Tinto selected the new Atlas Copco mobile miner machine concept for a number of reasons including the use of proven technology from the three previous mobile miner machines and other commercial products, as well as the ability to install complete ground support typical with high rock stress conditions at approximately 1,500 to 2,000 m (4,900 to 6,500 ft) depth. Atlas Copco, with support from Rowa, the Swiss company that specializes in back up systems for tunnel boring machines (TBM), is advancing the detail design of the access version of a tunneling system on behalf of Rio Tinto. Because of the different requirements between an excavation system for access tunnels and that for tunnels on the footprint, two different versions of the mobile miner machine technology were envisioned. The access and the footprint versions of the Atlas Copco mobile miner machine share a majority of key technologies and systems. Therefore, it was possible to conduct a performance conformation test using a full-scale version of the access machine that would also mitigate the technical risks for the footprint version. To alleviate confusion, this article focuses on the access version of the Atlas

Jul 1, 2010

By J. Andrew McGlenn, Greg Emslie, Murray Gant

The Second Narrows Water Supply Tunnel will ensure system reliability in the event of a major earthquake and increase the Greater Vancouver Water District’s capacity to meet a growing population’s longterm needs. It includes a bored tunnel between two deep shafts located in North Vancouver and Burnaby, BC, Canada. The support of excavation for the 16-meter-diameter (52.5 ft) TBM launch shaft consists of 83-meter-deep (272 ft) unreinforced concrete slurry walls. This paper discusses challenges encountered during construction of the launch shaft slurry walls, namely excavation methods and slurry loss, and mitigative solutions implemented to successfully complete the shaft with minimal impact to project schedule.

Dec 1, 2022

By F. Calizaya

This study summarizes the results of various numerical and laboratory experiments per-formed to study the effect of airflow recirculation on gas concentration. The numerical exercises were carried out on a simulated mine ventilation net-work. The laboratory experiments were conducted at the Mackay School of Mines' airflow monitoring system in Reno, Nevada. In both cases, the airflow was recirculated through the system by means of a main fan and a set of booster fans. The booster fans were positioned to produce two types of recirculation: In line and Cross-cut. For each type, various recirculation conditions were generated by changing the booster fan pressure. During each test, the gas emission rate at the simulated working face was kept constant. The study illustrates the conditions under which controlled airflow recirculation may be used to solve a district ventilation problem.

Jan 1, 1991

By William E. Mead

Although this paper has been entitled "Design of Embankments for Tailings Ponds and Waste Dumps," a better title might have been "Site Selection and Design Planning for Tailings Ponds and Waste Dumps," The procedures normally followed in performing the engineering calculations based upon the measured soil properties will not be detailed. Instead, we shall look at the subject in broader perspective which considers the environmental factors and the fundamental design principles. Disposal of waste materials left from the extraction and processing of mineral deposits has become, in recent years, an important engineering consideration for mine and mill operators. Land occupancy and land values almost everywhere are increasing at a rapid rate. So is the size of mine and mill waste dumps, thanks to our advancing technology in mineral beneficiation. Mining companies are being pressured to "clean up" their operations, both literally and in a safety hazard sense. Once, long ago, the miner could use any convenient location to get rid of his mine waste and mill tailings without being concerned over possible infringement on the rights and well-being of the public. Today, however, he must pay close attention to these matters if he wishes to avoid liability suits and the unfavorable reaction of civic groups as well as local and regional government. Most operators keenly sense their increased responsibility, not only because they are legally vulnerable, but because they realize the necessity for sharing space harmoniously with the rest of society.

Jan 1, 1967