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By Alexander N. Winchell

"The waters of Lake Superior flow into those of Lake Huron through the St. Mary's river. The rapids in this river are about half a mile wide and three-quarters of a mile long, in which distance the fall amounts to about twenty feet. Since this was the only obstacle to navigation between the west end of Lake Superior and ports on any of the other Great Lakes except Ontario, attempts were made many years ago to permit the passage of small boats from Lake Huron to Lake Superior by means of canals and locks. The first canal was built on the Canadian side of the river by the Northwest Fur Company in 1797-98. The lock was 38 feet long, 8 feet 9 inches wide and had a lift of 9 feet. A tow path was made along the shores for oxen to track the bateaux and canoes through the upper part of the rapids., The lock was destroyed during the war of 1812 by United States troops from Mackinac Island.The first ship canal, known as the State Canal, was built on the American side of the river in 1853-55, about 750,000 acres of land in Michigan having been granted by congress to a private company as a 'concession for its construction. This canal was more than a mile long, 65 feet wide at the bottom and 100 feet wide at the water's surface. It had two locks, each 350 feet long by 70 feet wide, with a lift of about 9 feet. The depth of water in the canal was about 13 feet and in the locks about 11 1/2 feet."

Jan 1, 1920

By Phillip J. Maddex

After the presentation of a co-authored paper, "The Cost of Transporting Ores and Raw Materials in World Markets", at the February SME meeting, one questioner commented, "You have been talking about the large shipper and ship loads. What does the small shipper do?" This paper will attempt to answer that question, at least in part. Probably the questioner hoped to hear about specific new tools and new techniques that he could apply. But one paper could only scratch the surface of the vast fund of information available; so rather than talk specifics we should take basics, that is, people, management and technology.

Jan 1, 1967

By G. W. Leney

Introduction and Historical Background The office and mining operations of Pacific Asbestos Corporation are located near Copperopolis, California in the foothills of the Sierras about fifty miles east of Stockton. This is historic country in the heart of the old Mother Lode gold district. Mark Twain's famous story of the jumping frog, written here, is still commemorated in an annual contest in Calaveras County,' and the camp at Poker Flats, described by Bret Harte, was only a few miles from the present mine.2 Joaquin Murrieta, the famous Mexican bandit started his three year reign of terror in this vicinity,3 and Black Bart, the P08 laureate of the stagecoach robbers, held up his first stage at Funk Hill, just three miles north of the mine. His last robbery was at almost the place, on the top of the hill overlooking the Stanislaus River ferry crossing. Although this was his favorite country, and he traveled extensively through it, he was not a credit to his acclaimed profession of Mining Engineer because there is no evidence that he ever recognized the asbestos, and he was finally caught as a consequence of the robbery at the ferry.4 One of the old stagecoach roads crossed the Stanislaus River at the mine site, and the ferry landing may still be seen from the main haul road into the pit. The road itself is partly buried under the rock dumps. In spite of its location and apparently prominent exposure, the first work on the asbestos deposit was not recorded until 1904.5 Development of the present operations was started in 1959 by Jefferson Lake Asbestos Corporation, a subsidiary of Jefferson Lake Sulphur Company. Management control of the company changed hands several times and it was later reorganized under the name of Pacific Asbestos Corporation. In December, 1968, a controlling interest was acquired by H. K. Porter Company, Inc. Figure (1) shows the mill and office buildings as seen from a site near the entry road. The offices are at the left with the mill warehouse in the foreground. The conveyor at left center carrys mine concentrates up the hill from the crusher. In the background are the dry rock storage building and mill tailings piles. Since the beginning of mining operations in 1962, seven and three-quarter million tons of ore and fifteen million tons of waste have been removed from the open pit which now measures about 1400 x 1800 feet at its widest points. The lowest operating level is at an elevation of 726 feet about 325 feet below the original surface. Figure (2) shows the open pit looking toward the west end. The main haul road can be seen along the side of the pit. A shovel is operating at the bottom of the pit while a front end loader on the level above provides ore for blending. In the background are rock dumps for waste stripping. The company markets an annual production of 30-35,000 tons of chrysotile fibre in groups 4 through 7, under the Mother Lode Brand

Jan 1, 1972

By D. Bradbury

Sufco coal mine, a subsidiary of Arch Western Bituminous Group, recently purchased a reverse osmosis (RO) system. The systems intent was to remove impurities in the water being mixed with the hydraulic oil to maintain the viability of critical longwall hydraulic systems and to prevent degradation. This project not only ensured hydraulic components from corrosion, but also revealed a cost savings by reducing the percentage of hydraulic oil mixed with the RO water. SUFCO WATER TREATMENT HISTORY Sufco coal mine has been in operation for approximately 70 years. Old works extend up to 15 miles one way, not including adjacent mined out longwall panels. Due to the geologic conditions and strata, water treatment has been as simple as putting water in at a high point of a mined out area and recovering it at a low point to discharge. Doing this reduces the total suspended solids (TSS) to less than 25 parts per million (ppm) and the total dissolved solids (TDS) less than 1,200 ppm which complies with Sufco?s water discharge permit. Even though the requirements for the permit were met, the water is still corrosive in nature. A portion of this water is piped back into the fireline (makeup) water system. It is then boosted to pressures of up to 500 psi to support mining sections, belt systems, equipment, fire fighting systems and the longwall.

Jan 1, 2011

By William R. Beloff, Franklin M. Grynkewicz, Puza

Construction of the MBTA Red Line Extension through Somerville, MA, called for driving twin tube tunnels through a zone of approximately 83m (273 ft) with mixed face conditions. While the majority of the tunnels were driven through competent hard rock using drill and blast techniques, the mixed face zone was advanced using floating crown bars for primary support. The overburden consisted of medium clay, underlain by water bearing glacial till, over a sloping bedrock surface. Due to the unusual nature of the construction techniques, a program was undertaken by the Contractor to monitor ground movement and stresses in the temporary steel supports. This paper presents a description of the instrumentation employed, as well as the measured ground movements and support stresses. Additionally, the tunneling techniques are briefly presented and commented upon. PROJECT DESCRIPTION The Davis Square to Porter Square Tunnel Contract is part of the Massachusetts Bay Transportation Authorities (MBTA) Red Line Extension from Harvard Square in Cambridge to the Alewife Brook Parkway via Somerville. The 5.1km (17,000 ft) Red Line Extension consists of four major new stations, three of which will be interlinked via tunnel construction, and the remaining station will be the last link of an open cut portion, and a terminal point for this phase of the extension. This 866m (2,790 ft) portion began at Porter Square in Cambridge and rose at a 4% slope through Somerville, terminating at the new Davis Square Station. Twin tube tunnels were constructed through 763m (2,517 ft) of rock and 83m (273 ft) of mixed face conditions at the Davis Square end. Figure 1 presents a plan view of the entire contract.

Jan 1, 1981

By Eduardo Velasco, Paz Navarro, Alfonso Navarro, Claudio Cimiotti, Alejandro Sanz, Nick Karlin

The LA Effluent Outfall tunnel is a 7-mile long, 18' internal diameter, secondary treated effluent discharge tunnel currently under construction by Dragados USA for the Los Angeles County Sanitation District No. 2 (LACSD). The purpose of this tunnel is to add redundancy and increased capacity for discharge of secondary treated effluent from the LACSD’s Joint Water Pollution Control Plant, located in Wilmington, California within Southern Los Angeles County. Current discharge from this facility flows through two existing tunnels of 8' and 12' horseshoe profile, constructed in 1937 and 1958, respectively. When the new tunnel is complete, it will add an additional capacity of 670MGD in peak wet weather flow conditions. Geology of the roughly 7 mile long tunnel was divided into six reaches by the contract documents. Tunnel Reaches (TR) 1 to 3, comprising 19,550' will be excavated in alluvial sands of the San Pedro and Lakewood formations, with cover ranging from 45 to 90 feet. In this reach the tunnel intersects the seismically active Palos Verdes fault Zone. TR 4 is a 1,600' transitional zone between alluvium and the rock formations of the Palos Verdes (PV) Hills, comprised mostly of Malaga Mudstone. TR’s 5 and 6 total 15,591', and are within the rock formations of the PV Hills with overburden ranging from 315' to 475'. The primary constituent of the PV Hills is Altamira

Jun 13, 2021

By John M. Moore

Within the Pofadder district of Namaqualand, South Africa, economically exploited deposits of bedded barite and zinc-lead-silver-copper sulfides occur in close proximity within highly metamorphosed mid-Proterozoic pre-tectonic para¬gneisses of the Namaqualand Metamorphic Complex (NMC) (figure i). The paragneisses belong to the Bushmanland Group (SACS, 1980) that comprises a relatively straight-forward regional sequence of basal leucogneisses, intermediate mica-sillimanite schists and glassy quartzites, and a mixed upper zone of banded iron formations (BIF), minor marbles, quartz muscovite schists and localised uppermost quartz-pebble conglomerates and amygdaloidal mafic gneisses (Joubert, 1974) (figure ii). The base metal and barite mineralisation occurs in close association with BIFs, generally above the glassy quartzites, although in some cases possibly below them. In the regional context, the Bushmanland Group paragneisses are, to the north, intercalated with and ultimately replaced by meta-volcanic sequences of talc-alkaline affinity (Reid, 1977) belonging to the Orange River Group (SACS, 1980). The metavolcanics are generally of acidic to intermediate composition and show evidence of subaerial formation from 'high altitude shield volcanism' with many acidic ashflow and welded tuff bands, mesocratic and lesser melanocratic lavas and some fanglomerates (Ritter, 1980). To the south and east, the schist/quartzite associations are initially intercalated with and eventually replaced by cordierite gneiss/metacarbonate/biotite gneiss associations of shallow marine affinity (Moore, 1980a). The Bushmanland Group paragneisses appear to represent sedimentary material in the extreme distal portions of a talc-alkaline volcanic environment adjacent to a shallow platform sea.

Jan 1, 1983

By Z. Sample

"INTRODUCTION This past year commodity prices continued their dip with increased volatility causing market values to slide another 16% putting increased pressure on even the largest companies to improve their free cash flow.[1] Without a recovery in commodity prices in sight, companies must find a sustainable method to improve returns in the current economic climate. In an effort to improve plant sustainability, the mineral processing industry is investing in advanced automation technologies and innovative processing methods that are both more reliable and more efficient than ever before. One such breakthrough technology is Heap Leaching (HL). This method of extraction has certain advantages over traditional metallurgical methods making previously unsustainable operations economically feasible. While HL is already seeing use in the gold and copper industries among others, recent developments may allow for the use of HL to process primary sulfide ores which make up about 80% of today’s ores.[2] For this reason, this emerging technology is poised for exciting growth. Unfortunately, as with any process change, the implementation of HL projects requires significant training on both the control system as well as the underlying process, and further, due to the complex nature of the HL process, this can be a particularly difficult task. DEMOGRAPHIC TIME BOMB Even before the implementation of these new technologies, the availability of the skilled workforce has already become a significant problem for the mining and mineral processing industries. From a survey of 912 mining professionals, Stratum International found that a mere 0.4% of senior level candidates were between the ages of 25 and 34 and a similar proportion aged over 75 years.[3] This indicates that there is both a deficiency of young skilled workers and a skilled workforce that is retiring earlier than the previous generation. Combined with data published by the US Department of Labor stating that the median age of the mining workforce is approaching 50 years old, research suggests that up to 50% of skilled mining and mineral process professionals are expected to retire in the next 5 years, leaving with their irreplaceable knowledge and experience.[4] While it is projected that the labor pool will be sufficient to fill open positions, the real question is if this young workforce will have necessary skill sets and experiences. In addition to a rapidly aging workforce and an inexperienced labor pool, a study done by the Oil and Gas Journal showed that it takes about 7 years, on average, for new workers to achieve a level of competency that permits them to assess risks and appropriately make decisions.[5] Not only is this figure is in direct conflict with the typical tenure of 5 years in one position meaning that the thinly spread skilled labor will be required to become senior staff before they are able to achieve competency in their current role, this also means that these millennials are not given the opportunity to become competent in their role before the retirement of the more experienced workforce."

Jan 1, 2016

By L. E. Murr

Solution flow in leach dumps and heaps or in columns of representative rock has been the subject of only limited studies. This is a regime involving unsaturated flow in semiconsolidated rock with a wide size distribution. Even the concepts of continuous flow systems are fairly recent, and have evolved from the search for better methods of operating industrial chemical reactors. (1-3) Waste rock consolidation and permeability play a key role in solution flow characteristics. Harris (4) suggested that bulk density variations in a leach dump could alter the particle-to-particle contact, and that large particle aggregates could act like single, large particles . In the limiting case where the bulk density approaches that of the undisturbed, consolidated rock, the entire waste unit would behave as a single particle. Roman (5) treated the phenomenon of bulk density and its effect on consolidation in terms of lixiviant flow paths or solution channeling in leach dumps. Like Harris, he assumed that no solution moved through particles or particle aggregates associated with zones of high bulk density. Solution flow paths are thus effectively separated by particle regimes, creating solution channels in the waste body. While some attempts have been made to describe solution flow in leach dumps and related systems by utilizing computer model approaches and laboratory- scale simulations (5,6), there have been no direct, large-scale observations of solution movement in channels or of the actual channel sizes and distributions within a waste body. This paper describes a series of experiments involving large-scale, controlled waste leaching tests, conducted over a period of several years, and aimed at providing some direct observation of the changes in waste consolidation and permeability, the size and distribution of solution channels, the movement of such channels with continued solution application, and other features relating to solution flow during the leaching of low-grade waste. These results are then combined with mineralogical information to explain observed leach behavior.

Jan 1, 1981

By James J. Fallon

The industrial minerals industry is defined loosely and a specific list is presented. Criteria by which to judge prospects and examples are provided. General trends of the industry are observed.

Jan 1, 1984

By Camillo Premoli

Namibia is one of Africa's newest nations. A German colony until 1915, it then became a South African protectorate until 1990, when it gained independence after an armed struggle that lasted more than two decades. However, no trace of past bitterness can be found today in the capital, Windhoek, or in the countryside. Namibia is now one of the safest parts of Africa. Namibia's industrial base and infrastructure have been untouched by war. Swapo, the ruling party, has embarked on a successful policy of reconciliation and economic development. The GNP per capita is a surprising $1500 (from the World Bank), one of the highest in Africa. Namibia's population stands at 1.3 million, including about 100,000 whites. Namibia is a very sparsely populated country (1.7 inhabitants per km2). About 70% of the people are farmers. Namibia has a surface area of 824,232 km2 (318,261 sq miles), about the size of France and Germany combined. The semi-arid climate and generally flat morphology make the country well suited to mineral exploration. About 40% of the country presents abundant rock outcrops. The rest is buried under the Kalahari sands. However, this cover in most of the country hardly exceeds 200 m (655 ft), and Australian technology has shown that large mineral deposits (Roxby Downs) can nowadays be found at even greater depths. Mining is Namibia's largest industry. In 1991, it accounted for 22% of the country's GDP, about 70% to 80% of its exports by value and 25% of internally generated government revenues. The Ministry of Mines and Energy (MME) is responsible for formulating and implementing national mineral policies. This agency has recently introduced legislation aimed at encouraging new and long-term investment in the mineral sector. The variety of Namibian mineral resources, both metallic and nonmetallic, is rivaled by few countries worldwide.

Jan 1, 1994

By Brian E. McGee

The Federal Coal Management Program represents the culmination of several years of effort by the Department of the Interior (001) to reformulate the manner in which coal owned by the United States is leased and developed. These efforts began in 1970 with a study by the Bureau of Land Management (BLM), which indicated that unless drastic changes were made in. the federal coal leasing procedures, federal coal lands would be leased almost for the asking while production of coal from those lands had been decreasing. Consequently, informal action was taken in 1971, which resulted in no further leasing being authorized until February, 1973. At that time, a formal moratorium on most coal leasing was established, with exceptions granted only for leases needed to satisfy short-term needs such as maintaining existing mines or supplying reserves for new contracts in the immediate future. This leasing policy embodied a long term objective of developing an entirely new planning system for federal coal leasing, as well as to schedule the preparation of a programmatic impact statement for this new system. As a result of the 1973 moratorium and the ensuing application of short-term criteria, only 10 federal coal leases (covering approximately 30,177 acres) were issued from February, 1973, through January l, 1976.

Jan 1, 1982

By B. Berhe, R. D. Lawrence, J. Hinzer

"The fortunes of mining companies and their implied value are tied to cycles - both economic and commodity – within which they operate. Hence the determination of appropriate future metal prices is one of the most critical factors faced by mineral valuators especially for advanced projects. Price, and hence revenue, is usually the most sensitive input to the valuation model. Empirical studies of past forecasts show that the success rate for commodity price forecasting is very poor. This paper explores various approaches and comments on their strengths and weaknesses. We conclude that careful evaluation of long-term metal prices is a key element and is hardly a luxury that can be left to simple averages or rules of thumb. INTRODUCTION Discounted Cash Flow (""DCF"") analysis, is well suited for the valuation of advanced mineral development assets, for which there are identified mineral resources and some form of economic assessment (Pre-Feasibility or Feasibility Study). The DCF method is also the most commonly used method for determining value for such assets. It provides a means of relating the magnitude of expected future cash flows from profits (or losses) to the magnitude of the initial cash flow (investment) needed for capital expenditures to purchase or to develop an asset for commercial production. The method proves useful in making investment decisions as it allows for the quantification of the Net Present Value (“NPV”), as well as the Internal Rate of Return (IRR) and Payback Period on initial investment capital. Valuation by its very nature is a forward-looking exercise. The DCF method attempts to estimate the NPV of expected future cash flows, by selecting factors that will likely affect future cash flow based on informed analysis. One of the most critical and sensitive factors is the determination of appropriate future commodity prices. “The variables that have the greatest impact on a DCF evaluation are the reserves, the metal prices, and the discount rate.”1 The determination of future commodity prices for valuation purpose or during M&A negotiations is a hotly contested issue. There are a number of analysts, institutions and specialized commercial data suppliers that provide both short and long-term commodities price forecasts. Also, the use of an aggregated mean for all available forecasts, or consensus forecasted prices for valuation purposes is not uncommon. The methods used in making forecasts for each forecaster may vary and in many cases may not be publically disclosed. Nonetheless, the aggregated mean of all forecasted commodity prices of reputed institutions is usually taken to “represent the market’s view of likely future commodity prices.”"

Jan 1, 2016

By Leslie G. McMillion

A field project to develop and demonstrate a method for alleviating problems of highly-mineralized ground water where they occur as isolated zones or pockets in fresh-water aquifers is being conducted in the Ogallala Aquifer of eastern New Mexico by the Robert S. Kerr Water Research Center. Removal of contaminated water is by a large-capacity well and the pumped poor-quality water is used locally for secondary recovery of oil, Benefits of the operation are threefold in that the aquifer is being reclaimed for future fresh water production, contaminated water is being used beneficially, and fresh water which otherwise would have been used for waterflooding is available for other purposes. Ground-water quality in the site has improved markedly after 21 months of operation. Water quality in 15 specially-drilled monitoring wells has returned to the original quality level of the aquifer, and chloride concen¬trations in the pumping well have dropped to half the maximum level recorded thus far. Project results are very favorable and provide guidelines for initiation of similar undertakings in localities where needed.

Jan 1, 1970

By A. Khoshnevisan

Molybdenum resources around the world are mainly associated with porphyry copper ores. Molybdenite (MoS2) is the main Mo mineral that has rhenium in its crystal lattice. This paper investigates the recovery of rhenium and molybdenum from a molybdenite concentrate using a hydrometallurgical treatment method. The molybdenite concentrate is leached with nitric acid and subjected to solvent extraction to recover and separate rhenium and molybdenum from the leached liquor. The effects of pH and the chemicals? concentration on extraction characteristics of Mo and Re are investigated to define the best condition for selective extraction of these metals. The tested leached liquor contained of 8.2 g/L Mo, 1.5 g/L Fe, 0.5 g/L Cu and 60 ppm Re. A good extraction efficiency, up to 94%, was achieved for Re from the leached liquor, where the extraction of other metals, such as Fe and Cu, was negligible. In particular, at very low pH, rhenium is extracted selectively from solution, while the extraction of molybdenum is less than 10%. After removing rhenium, molybdenum was extracted with LIX984N. The selectivity of molybdenum extraction over other metals in solution was significant. Nearly 94% of molybdenum can be extracted from the solution at a pH value of -0.12, without any interference from other metal ions such as copper and iron.

By Robert W. Gordon

The art of excavating tunnels with continuous, full-face boring machines began almost 90 years ago, in the early 1880's. At this time, Colonel Beaumont designed and manufactured a seven-foot diameter tunneler for boring under the English Channel, Despite the absence of modern materials and manufacturing techniques, Beaumont's tunneler, powered by compressed air piped in from the surface, was quite successful. During its short, but impressive existence, this machine set a record of advancing in chalk 50 feet per day for 53 days - which is impressive even by today's standards. Despite the apparent success of this early tunneler, almost 80 years passed before any further significant development was accomplished in this field. Demands from the construction and mining industry and society itself have motivated the development of the modern tunneling machine. Our rapidly growing civilization needs faster, less expensive and safer means of excavating tunnels. Space age technology and materials have played a major role in making hardrock tunneling machines possible.

Jan 1, 1970

By S. Bhattacharjee, S. K. Singh, R. K. Galgali

A method for the preparation of zirconia- toughened mullite using dc plasma is presented. An indigenously developed 50-kW thermal plasma reactor is used for the preparation of zirconia-toughened mullite using a dissociated zircon and alumina mixture. Both XRD and SEM studies of the product confirmed the formation of mullite and zirconia. The zirconia grew as equiaxed grains of uniform size (~5 µm) in a mullite matrix.

Jan 1, 2002

By William C. Beebe, Russell E. Martin

An account of driving and concreting two 900 m railroad tunnels for the Denver and Rio Grande Western Railroad under emergency conditions. Details the importance of on-site decision making by the Owner in completing the project successfully in record time. A general description of the geology and construction methods. The Thistle Drainage Tunnel drained water impounded behind the Thistle slide and serves as permanent diversion of the Spanish Fork River and Thistle Creek around the slide area. The project involved 684 meters of 5 m horseshoe tunnel, a 5 m diameter raised shaft and 23,000 cm of cut excavation.

Jan 1, 1985

By Peter Hall

The need for large volume covered storage has increased drastically in the last ten years. Increased world demand for such products as thermal coal, potash, metallic concentrates, etc., availability of land for large open storage and environmental issues have brought about this need. This paper discusses briefly demand, environment, types of covered storage and the Alternative Storage System "Eurosilo", a proven system for storage of dry bulk mateials in units up to 100,000 m3.

Jan 1, 1982

By G. F. Friel, J. C. Edwards, C. C. Hwang

In the implementation of a mine fire alarm and location strategy, the Interpretation of the fire signature Is Important. Smoke and CO are the two dominant fire signatures, and many mine fire detection systems utilize sensors which respond to smoke or CO through a diffusion mode or a mechanical pump mode. The fire signature may be modified during its transport along airways and at crosscuts. The modification occurs through dilution of the contaminants. In this Investigation, computer codes were employed to compute the effects of contaminant dilution on the contaminant signature when a straight flow passage has one dead-end crosscut. The model predicted the airflow within always and the entrainment of contaminants into the crosscut from the airway. One application of the model is to determine the most suitable location for CO detectors for early mine fire detection.

Jan 1, 1995