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By R. W. Brann, R. C. Freas

Franklin Industrial Minerals operates several mines/quarries, including two room and pillar underground mines. Both of these mines are operated as multiple level room and pillar including heading and bench operations on one or both of the levels. This paper focuses on Franklin’s Crab Orchard, Tennessee mine, which produces both high purity chemical grade limestone and crushed stone for construction applications. The high purity chemical specifications for the chemical grade limestone and filler/extender applications are inconsistent with the non-chemical rock being produced to supply the crushed stone market. As a consequence Franklin has developed a unique mine plan and operation to maintain both product balance and a safe and stable working environment.

Jan 1, 2003

By Jorma Miettunen

The Plant. The annual production of the Pyhasalmi mine is 900 000 tons of copper- zinc-pyrite ore containing approximately 0.7 % Cu, 2.5 % Zn and 30 % S. During 1976...1981 altered surface ore, 850 000 tons in all, was also treated at the concentrator. The surface ore was crushed and ground in a separate plant and was then fed into the copper or zinc flotation or was flotated in its own circuit, depending on the degree of alteration and the content of copper and zinc in the ore. The surface ore was exhausted in October 1981. Flotation comprises three consecutive flotation circuits; copper, zinc and pyrite circuit. The zinc circuit includes an open circuit roughing and scavenging. The scavenger concentrate and cleaner tailing are pumped to the middlings flotation. Rougher concentrates of the open circuit and the middlings flotation are pumped to cleaning which includes four stages. Figure 1 describes the flowsheet of the zinc circuit.

Jan 1, 1982

By Don Macfarlane, Brian Heer, Tom Martin

The Manapouri Power Station, commisioned in 1969, is located in Fiordland National Park in the South Island of New Zealand. It is the country’s largest hydro power scheme and can generate 700MW of electricity. The power station utilizes the hydraulic head of Lake Manapouri, using an underground power station and a 10 km-long tailrace tunnel was constructed by drill-and-blast to allow discharge to Doubtful Sound. Power generation fell short of expectations due to higher than expected friction in the tailrace system. To remedy this a second tailrace tunnel was constructed between June 1998and May 2002. It consisted of a 10 m diameter, 10 km long tunnel in predominately gneissic rock and was excavated using an Atlas Copco Robbins TBM. High water inflows, Owner/Contractor production incentives and a major claim settlement were handled during the 5 1/4 year project. This paper discusses TBM advance rates, utilization factors that increased in the second half of the project plus an innovative method for sealing Tunnel 1 to construct the bifurcation.

Jan 1, 2003

By J. Tuck

This paper reports on an ongoing exploratory research program which aims to develop an understanding of the relationships between mining companies and their stakeholders and the importance of corporate citizenship policies to reputation and hence to corporate sustainability. The findings of the first stages of this research, the results of a focus group and an expert opinion survey into the drivers of reputation for mining companies are reported. This study was undertaken to provide an understanding of the drivers of reputation for a number of stakeholder groups and the perceptions held by mining companies of these drivers for their stakeholder groups. Results indicate that drivers vary between stakeholder groups - that in the case of drivers common to a number of stakeholder groups they may vary in their importance across the groups, and that there may exist a divergence between industry?s perception and stake-holders? priorities. These results further the understanding of the relationship between corporate citizenship and reputation in the mining industry, thus assisting companies to strategically manage their corporate citizenship investments and assisting them in their transition to sustainable development.

Jan 1, 2007

By Gordon T. Clark

The preliminary design of four mined stations and 7.2 km (4.5 miles) of tunnels for Seattle’s light rail transit system is described. Constraints that influenced the design and options that were studied are discussed. The hilly post-glacial soft-ground geology of the Puget Sound Region pushed the alignment deep. Mined underground stations at depths up to 75 m (250 ft) and shafts with excavated diameters of 20-m (65-ft) are required. A 460 m (1,500 ft) sub-aqueous crossing of Portage Bay and undercrossing of an active 12-lane multi-level freeway were two of the more significant design constraints.

Jan 1, 2001

By Thomas P. Kwiatkowski, Joginder S. Bhore, Christopher D. Orlandi, Jose Velez

Three case histories of successful TBM tunneling for New York City Water Tunnel No. 3 are presented. The tunnels, costing about one billion dollars total, are the 5-milelong, 18'-11" OD Brooklyn Tunnel; the 5-mile long, 23'-2" OD Queens Tunnel, and the9-mile long, 12'-4" OD Manhattan Tunnel. The three tunnels are the first major tunnels constructed in New York City rock utilizing the TBM method of construction. This paper describes and compares the three tunnel projects in terms of geology, construction methods, TBM’s, rock and groundwater behavior, rates of advance and other performance data, and challenges and solutions encountered during the projects.

Jan 1, 2007

By J. O. Voigt

No major changes took place in the salt industry during 2004. No new uses of salt appeared and only localized supply disruptions occurred. Many salt producers reported slightly increased salt sales and profits for the year. In the United States, about half of the salt supply is produced as brine, by solution mining, and is used by the chemicals industry. One-third of U.S. salt is produced as rock salt by 14 underground mines. The remaining two production techniques, each with less than 10 percent of the total tonnage, are vacuum-pan-evaporation for refined, food-grade salt, and solar pond crystallized salt.

Jan 1, 2005

By Scott G. Britton

Up to now, the hands-on approach to construction has been stressed. This chapter reviews the basic tools available for construction design and monitoring of a construction project. It is divided into three discussions, all under the general title of computer aids, since the trend for using these tools-is via the computer. In the context of our discussions, the focus for computer aids will be on the use of evaluation and analysis techniques for coal mine construction applications, including mainframe programs, CPM techniques, as well as mini and microcomputer applications. Although the presentation of material in this chapter may be detailed at times, by no means does it cover the entire field of computer applications for design or project scheduling and monitoring. It is only an attempt to illustrate the possibilities that are available to construction and mine engineers. Interested persons can pursue computer applications for coal mining by reviewing Computer Methods for the 80's. by Alfred Weiss, editor, published by SME-AIME.

Jan 1, 1983

By John E. Litz, Charles W. Kenney, Wayne Carter

Refractory gold ore pretreatment processes continue to receive much attention. This paper compares the relative economics of treating ores by oxygen pressure oxidation, roasting and bacterial oxidation with or without preconcentration by froth flotation. Capital and operating cost estimates for each method of pretreatment were prepared and these estimated costs and ore sulfide grades then are used to compare the process economics. The study indicates that the most significant item affecting the economics is the amenability of the ore to flotation. The cost benefits of flotation are $10-13 per tonne ore processed (2%-4% s=, 10:1 ratio of concentration). In most cases bacterial oxidation has the lowest overall cost, especially if less than complete oxidation of the sulfides will give acceptable recovery, however bacterial oxidation has yet to be practiced on a large scale. In all situations pressure oxidation shows the highest cost. However, the cost differences between the treatments are small, less than $7 per tonne.

Jan 1, 1990

Coal has been mined in the central Appalachian coalfields of southern West Virginia, western Virginia, and eastern Kentucky for more than a century. The dwindling reserve base consists in large part of coal that would have been considered unmineable by earlier generations. Nearly every current operation is working on a property where coal has been extracted in the past, from seams either above, below, or both. NIOSH is conducting research aimed at helping mine planners prevent hazardous conditions due to multiple seam interactions. To-date, more than 300 case histories have been collected from underground mines, mainly from central Appalachia. This paper focuses on several of the more challenging situations that have been encountered, including: • Room-and-pillar development 20 ft (6 m) beneath full extraction workings at a depth of 1,000 ft (300m) of cover (Virginia) • Pillar recovery 45 ft above full extraction workings at 900 ft (270 m) of cover (Virginia) • Near-simultaneous room-and-pillar mining with pillar recovery with 40 ft (12 m) of interburden and 1,500-2,000 ft (450-600 m) of cover (Kentucky) • Longwall mining directly beneath main entries in overlying seams (West Virginia) • Some of these operations have been highly successful in overcoming the challenges, others less so. The lessons learned from their experience will help ensure that these and similar difficult reserves can be mined safely.

Jan 1, 2006

By Fulian He, Jianhang Chen, Shoubao Zhang

"Fully grouted rock bolts have been used in mining industry for many years. Significant research has been conducted to evaluate the load transfer behavior of fully grouted rock bolts with experimental programs. However, compared with that, less work has been conducted with analytical modelling. Therefore, in this paper, the authors used an analytical model to study the load transfer behavior of fully grouted rock bolts. To confirm the credibility of this analytical model, an in-situ pull-out test was used to validate this model. There was a close match between the experimental result and the analytical result. Following this, a parametric study was conducted with this analytical model. The influence of coefficients, Young’s modulus of the rock bolt and the diameter of the rock bolt on the load transfer performance of rock bolts were studied. Furthermore, the load distribution along the fully grouted rock bolt was analytically studied. The results show that the axial load in the rock bolt decayed from the loaded end to the free end independent of the pull-out load. However, the trend of the load distribution curve was influenced by the pull-out load. This paper was beneficial to better understand the load transfer mechanism of fully grouted rock bolts.INTRODUCTIONRock bolts have been used in the mining industry for a long time. They are used as the reinforcement tendons to keep the stability of openings in underground mining and the slope in open-pit mining. Furthermore, rock bolts are commonly used not only in the mining engineering, but also in civil engineering (Thompson, Villaescusa, and Windsor, 2012).The rock bolt is a tendon which can be a rod or a cable inserted into a borehole drilled in rock masses or soils. Traditionally, the material of rock bolts was steel. However, engineering practices showed that the steel rock bolts can be easily corroded by the moist environment in underground mines. Next, Fiber Reinforced Polymer (FRP) was used to manufacture rock bolts, which are termed as FRP rock bolts. Experimental results proved that the FRP rock bolts can effectively reinforce the surrounding rock masses without being corroded (Wang et al., 2018)."

Jan 1, 2019

By Herbert F. Nyberg

The Black River Falls Mine is owned and operated by Jackson County Iron Company, a wholly owned subsidiary of Inland Steel Company. It is located in vest central Wisconsin, seven miles east of the city of Black River Falls. This is the first taconite plant in the state of Wisconsin. Iron mining started in this area in 1856 but soon failed due to the low grade ore and crude methods of mining and transportation. Inland Steel Company acquired the property in 1939. Some drilling and test work was done in 1940, but the economics of developing the property at that time were not favolable. Improved methods of concentrating and pelletizing in the 1960's made it possible to build the present plant. Due to the limited ore reserve of 45,000,000 tons with expected recovery of 33% it was necessary to limit the capacity of the operation to 750,000 TPY with a life of 20 years. There was some concern about an operation of such limited capacity. A million ton operation was considered the minimum size plant for a profitable operation.

Jan 1, 1976

By Jeff Salai

The CP-3A contract is the final segment of the MWWST’s 28.3 km (17.6 mile)pressurized water supply tunnel for the metropolitan Boston area. The 1,288 m (4,226 feet) of U-shaped tunnel alignment passed through five rock zones employing four different primary support systems. The short tunnel began in Weston, Massachusetts, at Shaft 5A in soft, completely weathered argillite, passed through a fault zone, and ended in Dedham granite. An 18-foot diameter horseshoe starter tunnel was built to accommodate a 4.94 m (16-foot 2 1 / 2 inch) diameter Robbins TBM. Heavy water inflows were anticipated and subsequently encountered during probe drilling. Pre-excavation grouting was implemented at high pressures to displace high water inflows in the starter tunnel and consolidate the fault zone. This paper will provide an overview of the tunnel construction with an emphasis on ground control, grouting and survey control.

Jan 1, 2001

By Georgy Cherkashov, Svetlana Babaeva, Tamara Stepanova, Firstova. Anna

Seafloor massive sulfides (SMS) study in the Russian Exploration Area at the northern equatorial Mid Atlantic Ridge began after signing the contract with International Seabed Authority in 2012. In order to evaluate the SMS resources in the course of exploration the major and rare metals with economic value should be determined. The evaluation is based on geochemistry and mineralogy and particularly on the type of rare metals occurrence in the SMS. As a case study research of the Semyenov cluster of SMS deposits have been conducted.

Sep 1, 2014

By F. -J. Wodopia

Sustainability of energy supplies has been an issue of general interest for a long time. Whilst in the past the continuous productive use of natural commodities was in the fore, its compatibility with the environment and climate and ultimately also social aspects have recently gained more and more attention. Today many discussions focus on the climate compatibility of individual options to act. Fossil fuels, in particular coal and lignite, are generally challenged because coal use makes a significant contribution to global man-made CO2 emissions. The drastic increase in the consumption of fossil fuels is not explained by the fact that coal utilisation technologies are not or cannot be sustainable but rather by the growing world population and the endeavours numerous national economies trying to catch up economically. Coal is the world’s No. 1 fuel and, in the view of many experts, will keep this position also in the foreseeable future. The access to its deposits plays a significant role for the economies of the emerging countries. Consequently the aspects of energy security and economic efficiency need to be considered at eye level with climate compatibility. In Germany, however, the public acceptance of fossil fuels and of large industrial projects is in the focus of attention.

Jan 1, 2011

By Desiree Willis

Disc cutters have determined excavation rates of rock tunneling projects for more than 50 years. First developed in 1956 by James S. Robbins, disc cutters (then 279 mm or 11 in. in diameter) were used to bore limestone of 190 MPa (27,500 psi) unconfined compressive strength (UCS) and were loaded with 7.12 t (15,700 lbs) each. Modern cutters have reached up to 508 mm (20 in.) in diameter and are typically loaded with up to 31.7 t (70,000 lb) to economically bore through the hardest of rock up to plus 400 MPa (60,000 psi) UCS. New developments, such as larger cutter diameters, are geared to increasing the bearing capacity and wear life of the cutting structure. This, in turn, increases cutter life, cutter load and cutter penetration. Disc cutters have also been re-designed on a small scale for use in hard-rock utility installations. Additional variables also affect the three factors, including cutter spacing on the cutterhead, cutterhead diameter and cutter materials.

Jan 1, 2007

By C. Menidiatis

The first cement plant of TITAN Cement Co was founded in Elefsis in 1902. It was the first cement industrial facility to operate in the Balkans and in the Eastern Mediterranean region. Currently have four cement plants in Greece producing 5.4 million tons per annum, and 25 ready-mixed concrete sites producing 1.4 million m3 annually. It has a total of 20 quarries, 14 of which are producing materials used in the making of cement while the remaining six produce aggregates used in the production of ready-mixed concrete. All plants in Greece are accredited for ISO 14001. The restoration of quarries began in 1976 at the company?s limestone quarry of the Patras plant, and was soon extended to all quarries. At that time, a department responsible for all environmental issues was established. To date, over 700.000 shrubs and trees have been planted and maintained at quarries, plants and ready-mixed concrete facilities, while over 100,000 trees have been donated to municipalities, communities, customers and to the Greek state.

Jan 1, 2002

By J. A. Herbst, L. B. Hales, R. Zaragoza

INTRODUCTION The Control Problem The need for automatic control in flotation plants stems from frequent and randomly occurring disturbances to the feed slurry. Typical disturbances occur in the solids feedrate, the slurry percent sol ids, and the mineralogy and flotability of the gangue and valuable minerals. In plants where semi -autogenous grinding mills (SAG) are used, feedrate changes are very large and changes in feed percent solids of 1m or more are common. Mineralogy changes between valuable minerals are common, as are changes in the host gangue rock. As these changes occur, the operator can attempt to compensate for them by making adjustments to the flotation cell levels, the dosage rates of the collectors and frothers, the pH, and in some cases the aeration rate of the cells. This problem is sometimes complicated by the fact that different sections of the flotation plant will be processing different ore types at the same time. Potential Savings with Control Flotation control brings about savings or plant improvements in two areas; the first is in improved metallurgy and the second is in reagent savings. Improved metallurgy includes increases in the average plant recovery and achieves target concentrate grade level s more consistently. Average recovery increases between 1.0 and 5.0 percentage points have been widely reported (Paakkinen, 1979; Sutherland, 1984). Reagent savings of up to 40 percent have also been reported (Hales, 1985). VARIABLES OF IMPORTANCE Control led, Manipulated, and Disturbance Variables The initial step in the analysis of the flotation control problem is identification of important variables which can affect the efficiency of separation. The efficiency of separation is represented by a group of controlled variables which can quantify the performance of a flotation circuit. This group includes variables such as grade, recovery, tonnage through- put, and circulating loads. The efficiency of separation of a flotation circuit may generally be defined by a grade recovery map, where each point on this map re- presents a set of operating conditions (see Figure 1). However, the combination of operating conditions must be set to operate close to the economic optimum. The group of operating variables which are changed in order to achieve desired circuit performance are called manipulated variables and can be classified into two

Jan 1, 1986

By Tor L. Brekke, Alberto Marulanda P.

The paper describes hazardous water inflows during construction that have taken place over the last three years in tunnels in Colombia. The projects involved are the Chivor II Hydroelectric Power Project (penstock tunnel), and the Chingaza Water Project (two tunnels). In all cases, loss of face control led to significant loss of ground; in one case some 70,000 m3 of slide material was involved, much of which came out through the portal situated 1.6 km from the face. Emphasis is given to: (a) the geologic setting, (b) the remedial measures taken, and (c) the main efforts that can be made to prevent hazardous conditions from developing.

Jan 1, 1981

By John William Carlson

The Y2K or "Millenium" bug is a tiny critter, comprising no more than two digits in a date field. This bug, like its' more lethal cousins of biological and computer virus fame, has the potential to derail the economy of the U.S. and the rest of world. Whatever the reader's perception, rest assured that you will be affected by Y2K along with every person in the civilized world. How did we get to this position? It is really quite simple. The Y2K problem is a creation of computer programmers who, in an effort to conserve valuable memory in the early days of computer development, used two digits as shorthand- to define the year in date sensitive applications. Instead of typing in "1982," our experts employed "82." They believed-correctly­that the problem of limited memory would be solved by technology and assumed (nasty word) that software would be modified to take care of any problems associated with a date rollover in the year 2000. Their assumption resulted in the problem facing us today.

Jan 1, 1999