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By Ivano Andreis, Georgios Kalamaras, Mario Liti, Sebastiano Pelizza, Filippo Avesani

"THE SS640 AGRIGENTO-CALTANISSETTA PROJECT The Caltanissetta tunnel is part of the works for the construction of the second 28km-long maxi section of the SS 640 motorway of Porto Empedocle, from km 44 to the junction of Imera in Sicilian hinterland. Amongst other major infrastructure works, the €740 million ANAS (Italian national roads and highway administration agency) project consists of four twin tube tunnels three of which are being excavated by conventional means. The longest tunnel, underpasses the Caltanissetta city and has a length of 3.9km under a maximum overburden of 120m. The JV consisting of CMC of Ravenna and TECNIS SpA won the design & built tender in 2010. Construction started in early spring 2012 following the approval of detailed design and later on the approval of design for construction. THE CALTANISSETTA TUNNEL The Design Phase Tender design and detailed design foresaw the construction of 13.4m excavation diameter tunnels that were to be enlarged in a second phase to create, every 600m, 50m-long tunnel sections for emergency parking. During the design for construction project phase the JV proposed to replace the 13.4m tunnel with a 15.08 excavation diameter that incorporated apart from the two 3.75m wide lanes a 3.25m wide continuous emergency lane. This significant tunnel section modification was associated with better road safety conditions, simpler and safer construction procedures, better statics for the tunnel section while in terms of overall cost the solutions were equivalent.Geologic context The tunnel is located in the middle of the geologically known Caltanissetta basin that is intersected by various tectonic structures. The geologic context for the tunnel scale, was defined in collaboration with the University of Catania in early project phases. For almost its entire length the tunnel is excavated in the Terravecchia formation that represents the lower part of the stratigraphic sequence that was formed in the Tortoniano period of Miocene. The quite complex geological model is also characterized by the presence of the so-called Trubi formation that consists of clay and marl clay. Almost 90% of the tunnel traverses formations that are quite similar in terms of excavation behavior. Exception to this are thrust zones and a calcareous stretch of the alignment. This last segment has a length of 200m and was identified since the very beginning as a tunneling challenge due to the combination of very poor geotechnical properties and an important water load."

Jan 1, 2016

By G. S. Walker, W. van Bronswijk

The accurate determination of free cyanide and metal cyanide complexes is of increasing interest to Carbon-in-Pulp (CIP) gold extraction operations as cyanide consumption is an important economic factor in the processing of complex ores. Characteristically complex ores are high cyanide consumers and these ores usually contain a range of sulfide minerals e.g. covellite (CuS), digenite (Cu1,S), chalcocite (Cu, S), Pyrrhotite (Feci-x)S), marcasite (FeS2), arsenic and antimony sulfides and zinc sulfide. These minerals can consume significant quantities of cyanide, e.g. various copper(!) cyanide complexes such as CuCN, Cu(CN)2·, Cu(CN)/ and Cu(CN)/ can form, depending on the cyanide to copper ratio in solution. Measurement of free and complexed cyanide is thus a prerequisite for efficient cyanide dosage control. Free cyanide can be determined potentiometrically or amperometrically but the methods are prone to error and are laborious [1]. Metal cyanide complexes can be determined by reverse phase HPLC, however, the species ofa single cation (e.g. Cu(CN)i-, Cu(CN);2 and Cu(CN)/) elute as one species [2]. Additionally the high amount of suspended matter in CIP leach solutions tends to introduce errors. Raman spectroscopy has the potential to be used as an in­line or on-line method of analysis. Free cyanide and the cyanides of gold, silver, copper and iron have been studied in aqueous alkaline solutions with a view to developing such a method. Spectra were obtained with a Bruker RFSl00 FT-Raman spectrometer using a 1064 nm laser delivering 800 mW of power at the sample. Depending on the solution, 250, 1000 or 4000 scans at 4 cm-1 resolution were accumulated. The cyanide stretches observed were relatively narrow (10 15 cm-1 full width at half height) and well resolved (Figure 1 ).

Jan 1, 1995

By Robert C. Jones

The Henderson Mine, a new large scale underground development, is being developed by AMAX. The mine site is located about 50 miles west of Denver, Colorado, adjacent to the east side of the Continental Divide. The mine's three access shafts are in a narrow alpine canyon at an elevation of 10,400 feet. The ore body of molybdenite is to the south of the shafts, 3,000 feet below the surface of nearby Red Mountain. The ore extends over 800 feet vertically and is about 1,700 feet by 2,200 feet horizontally. The eastern and southeastern boundaries of the deposit are still to be defined at the present time. Development mining is advancing at the mine site on a three shift, seven-day basis at the rate of about 2,000 feet per month. About twelve miles of heading have been driven at the present time, and work to sink No. 3 Shaft has started. Development mining was begun in 1967 with the sinking of No. 1 Shaft. This shaft is fully concreted, 23 feet in diameter and 2,441 feet in depth. It is the mine ventilation exhaust conduit. It is also used for development muck hoisting, stand-by mine water pumping and secondary access to the 8,035 foot level. This level is the mine exhaust ventilation level and was mined principally by conventional rail mining methods. From this one station at the 8,035 foot elevation a 5% ramp was driven to the initial production horizon at 8,100 feet with diesel rubber tired mining equipment. Subsequent mining has been entirely by mobile diesel equipment at the mine site.

Jan 1, 1974

By Reed J. Irvine

One normally does not find sudden and dramatic changes in the investment climate, barring the unexpected outbreak of-wars or revolutions. Asia has seen a fair amount of military action and revolt during the past year, not all of it unexpected There was the fighting in Laos, which resulted in the as yet unconcluded negotiations which will probably lead to the establishment of a neutralist regime. In April of 1961 another revolution occurred in South Korea, and the elected government was replaced by a military dictatorship.. Communist guerrilla activity in South Vietnam was stepped up, and uncertainty about the future of that area increased. Relations between Pakistan and Afghanistan became more strained, and while no fighting has broken out, diplomatic relations between the two countries were broken off. India was both the victim of further incursions of her territory by communist China and the perpetrator of the forcible seizure of territory from Portugal. Indonesia has been making preparations for an armed attack on the Dutch in New Guinea.

Jan 1, 1962

By Yong Pan, SRIVATSAN JAYARAMAN SRIDHARAN, Purushotham Tukkaraja

The block cave mining method poses unique ventilation challenges compared to other underground metal mining methods. This research study focuses on assessing the airflow behavior in regulated airflow distribution systems by developing a 1:100 scaled block cave experimental model and a numerical model. This study also investigated gas flow behavior under various airflow conditions. Based on our findings, we observed that reduction in particle size and porosity of caved materials, decrease in cave footprint, and closure of undercut drifts would increase cave airflow resistance. The increased airflow is found to be beneficial for gas dilution regardless of its source locations, while the regulated airflow distribution system might deteriorate the gas dilution situation when the source is located in the extraction drifts.

Sep 1, 2022

By C. H. Smith

The present interest in beryllium seems to be the result of recent developments in the uses for the metal discovery of significant deposits of disseminated beryllium ores, and the development of chemical and physical processing techniques, for recovering the beryllium values contained in these ores. At the present time most of the new and potential uses for beryllium are in the research stage of development and are not consuming large quantities of the metal. However, they do point to an expanding market. Interesting new discoveries or extensions of previously known deposits have been reported during the past year from the Boomer Mine in Colorado, the Mesquite area of Nevada,, the Chemalloy pegmatites in Canada, the Brazilian and African pegmatite districts and from other areas, However, this paper will discuss only four of the beryllium deposits, which appear to be of special significance due to their; large reserves of ore and promise economic development. The new chemical and physical processing techniques are not discussed in detail, but it should be stressed that the development of an economical process to handle the pegmatitic and low-grade non-pegmatitic beryllium ores is of great importance to the development of the beryllium industry. Scientists in both government and industry are co-operating in this effort and it is expected that commercial processes will be developed in the near future.

Jan 1, 1962

By Matteo Cortinovis, Giuseppe Gelmi

"INTRODUCTIONEdilmac dei F.lli Maccabelli (hereinafter referred to as Edilmac) has recently developed a special civil engineering application using the Raise Boring technology with the assistance of Inrock MGS (Magnetic Guidance System). Applying the Paratrack Magnetic Guidance System coupled with a directional mud motor to the drill string allows a better accuracy compared to standard drilling, as showed in our tests. This is the first time the Paratrack System has been applied to the Raise Boring technology. RAISE BORING METHOD STATEMENT The Raise Boring technology was born in North America during the Sixties. In 1962, Ingersoll and Robbins were the first companies to produce Raise Boring Machines (RBM). The technology was first used in the underground mine industry, in order to bore ventilation shafts and passes through different levels, thus reducing the cost of haulage. The Raise Boring method is only feasible in stable rock conditions. The Raise Boring method consists of drilling a small diameter pilot hole that reaches a tunnel located at the bottom of the drilled hole. Once the pilot hole reaches the tunnel, a reamer head is installed at the end of the drill string and pulled up, creating the hole with the designed diameter (Figures 1 and 2). The main equipment, which is required to perform Raise Boring activities, is the following: •,An RBM; •,A tricone bit; •,Drilling rods; •,A reaming head; The standard mucking of the pilot hole is done with water or bentonite mud. For the last 30 years, Edilmac has developed a mucking process, which uses compressed air with the addition of foam or a small amount of water for dust control.Pilot hole tricone. The drilling of the pilot hole is usually performed with a tricone bit having a diameter between 11” (27.61 cm) and 15” (38.10 cm) (Figure 3). High strength rods. They generally have a diameter ranging from 10” (25.40 cm) to 12 ?” (32.70 cm) (Figure 4), depending on the length and the final diameter of the shaft."

Jan 1, 2016

By L. L. Lien

In this economic age of high interest rates and softening mineral commodity markets, the mining industry is taking a hard look at how it conducts its business and where economies can be effected. The capital investment to build a new metallurgical facility or open a new property has traditionally attracted substantial investigation, analysis and management attention. The areas of mineral exploitation, financial feasibility, engineering and construction have been studied extensively and their management, although still difficult, have become refined disciplines.

Jan 1, 1982

By Donald A. Dahlstrom, Wai-Ping Kam

The mineral industry and individual processing plants are large consumers of energy. While energy conservation has received some attention in the present Federal Administration National Energy Strategy proposal it is obvious that the mineral industry should also continue to emphasize energy consumption reduction for important economic savings alone. As indicated by other studies, comminution is the largest single consumer of energy in the mineral processing plant (1.3% of total electrical energy consumption in the U.S.A.).1 Fine grinding is the largest portion of this amazing statistic. While substantial energy savings have been demonstrated by new machine developments and improved control methods, undoubtedly there are additional areas in comminution where substantial progress can be made. Some time ago, the U.S. Department of Energy published a report on "Comminution and Energy Consumption" by a committee composed of experts in the field of comminution from industry and academia. They identified the following potential for energy savings by specific areas? Classification device design 9-13% Comminution device design 3-16% Control 9% Grinding additive 3-6% Materials 3% It is apparent that the classification device had the first or second highest savings potential. Obviously, serious research consideration must be given to this technology area. A series of three papers have previously been written on the subject of two stage classification research work for ball mill operation by the authors. Accordingly, a brief review will be made. Previous Research Results on Two Stage Classification The hydrocyclone was selected as the type of classification equipment for this study as it represents by far the majority of the devices used in ball milling. While four different hydrocyclone circuits have been proposed by others,3 only two were considered in this work as illustrated in Figure 1. Flowsheet A is truly counter-current in nature in that the product from the ball milling circuit is taken from the first stage overflow

Jan 1, 1992

By S. K. Kawatra, V. Claremboux, S. Valluri

Carbon dioxide capture from coal-fired power plant flue gas and subsequent sequestration is expected to play a vital role in mitigating global climate change. To meet the growing need for CO2 capture Technology, Michigan Technological University is researching CO2 capture and Utilization. We have successfully converted CO2 into oxalic acid using an electrochemical approach. If oxalic acid can be produced in bulk from CO2, it can be used to leach rare earth minerals at low cost. Electrochemical reduction of CO2 to hydrocarbons and other chemicals is a complex multistep reaction with adsorbed intermediates. The exact reaction mechanisms leading to various products are not clear from the literature to date and will likely change over the range of conditions like pH, electrode potential, electrolyte medium, catalyst, etc. In this paper, we will present an idea of how the factors mentioned above will effect the electrochemical reduction of CO2 to Oxalic acid. INTRODUCTION. CO2 is thermodynamically quite stable, as shown by its highly negative heat of formation. Thus, it is expected that the formation of any useful chemical from CO2 will require the input of at least as much energy as geological sequestration. However, to be more effective the resulting economic value of the chemical need only pass the cost of the additional energy required beyond geological sequestration. This lends itself to two extremes: one where the quantity of energy required is low and one where the economic value of the additional energy is low. It is expected that CO2 can be reduced via electrolysis to several compounds. Of particular interest are formic acid, oxalic acid, methanol, ethanol, formaldehyde, and carbon monoxide (as a component to syn-gas). These chemicals have been reported as electrolytic products previously in literature and have considerable potential for application. EXPERIMENTAL Electrocatalytic Production of Oxalate from CO2 We are using membrane electrolysis cell to produce oxalate from CO2. A membrane electrolysis cell is a 2-chamber electrolysis cell where the chambers are separated by a selectively permeable membrane. To produce oxalate, a cation exchange membrane (which selectively exchanges cations) was used. Previous literature suggests that in the cathode chamber an organic electrolyte, such as tetraethylammonium perchlorate or tetraethylammonium bromide in dimethylformamide, are preferred3. In the anode chamber, a sodium hydroxide solution water is used. Carbon dioxide is then bubbled into the cathode chamber as a current is applied.

Jan 1, 2019

By E. Lovera

Social attention to environmental aspects, steadily increasing in European Countries, has been leading to a stricter regulation of many productive activities. Among them, mining and quarrying sectors have been often censured for their potential and real impacts on land and environment. Referring to dimension stone exploitation (also the terms ornamental stone or natural stone are here used as synonymous), quarries are often concentrated in extractive basins, where the resource is localized with suitable quality and quantity: this fact has sometimes raised critical environmental situations. Nevertheless, dimension stone quarrying represents in Europe a traditional and important economical activity, source of wealth and employment. Moreover, many natural stones take on a ?cultural? value and may be considered as ?classic?, as they have been exploited since antiquity and are element of the architectural heritage of many Countries. The sector relevance demands the research of a sustainable balance between social-economical needs and environmental protection. Actually, very restrictive environmental protection policies have led to severe limitations to quarrying activity, but the results do not seem to be completely positive in terms of sustainability: on the one hand, closing-down stone quarrying activities imposes a shrinkage in local, social and economical development; on the other, quarrying activity is pushed towards developing Countries, environmentally un-protected, simply moving and putting off to next future the problem. The challenge of the sustainable development of quarrying sector ? recently explored in the European Commission?s communication ?Promoting sustainable development in the EU non energy extractive industry? (COM-2000-265) ? should be achieved through a positive link between theoretical statements and practical effects: sustainability indicators may be an effective instrument to assess and monitor the environmental performance of the industry. The paper refers to the development of specific ecological criteria and indicators, which can be useful to measure and predict the eco-efficiency of a dimension stone quarry, finally pointing out where improvement efforts have to be focused.

Jan 1, 2003

By I. H. Warren

Hydrometallurgy has a well-known and established role in the production of manganese metal (1) and manganese compounds, including battery grade manganese dioxide (2). Also, several leaching processes have been developed and applied at various times for the recovery of manganese from low grade ores (3). Recently, interest in the hydrometallurgy of manganese has been stimulated by the problems presented in the processing of sea nodules (4). Fumes and dusts from the ferro-manganese furnaces also offer a potential field for the application of manganese leaching techniques (5). In treating low grade manganese ores a major requirement of the leaching process is that it should dissolve manganese from a mixture of manganese and iron oxides. The most selective reagent for this purpose is ammonium carbamate applied after preliminary pyrometallurgical reduction of the ore (6). Since soluble carbamate complexes of the postulated type (7) are formed by both manganous and ferrous, but by neither manganic nor ferric, ions, selectivety of manganese leaching is achieved by control of the reduction operation to yield, essentially MnO and Fe304? A potential improvement to this two step process would be to simultaneously reduce and selectively leach the manganese in one hydrometallurgical operation. This possibility has been experimentally studied and the results are described below. During the preliminary study of the stability of solutions of ammonium, ferrous and manganous carbamates at elevated temperatures, it was observed, contrary to the observation of Welsh (8) at lower temperatures, that

Jan 1, 1971

By Joyce Lappin-Randolph

In 1977, Vertical Crater Retreat (VCR) Mining was developed at the Homestake Mine and by 1983 had become a fully integrated mining method contributing 60% to total underground production. VCR has proven successful for continuous ore blocks exceeding 55,100 tons (50,000 st) with dips greater than 60" and provides a productivity average of 39 tons (35 st) per man shift (tpms) which is 92% greater than Open Cut-and-Fill. Discontinuous ore bodies, small pods, or flat structures not amenable to bulk systems are mined with Mechanized Cut-and-Fill (MCF) and have been able to achieve a 32 tpms (29 st) average productivity. Small, low grade, remnant ore bodies were not economically viable with large scale bulk techniques and couldn't support the development required for a MCF system. As a result, Homestake began researching modified bulk mining methods to increase production rates and maintain safety, while lowering costs. A modified version of VCR with significantly diminished development was prototyped in an effort to reduce initial capital investment and expedite the production phase. This modified method is called Small Block Vertical Crater Retreat (S. B. VCR). Geology The Homestake Gold Mine is located in the northern Black Hills of South Dakota at Lead. Having been active since 1876, it now extends from the surface to the 2,440 m (8000 ft) level underground.

Jan 1, 1987

By Lawrence A. Roe

This paper describes research and development efforts leading to a wet process for the beneficiation of Western talc ores in which the values are primarily present as soft, platy talc mineral. The mineralogy of the ore, as it relates to the logic of utilizing an uncomplicated, attrition-scrubbing sedimentation process is described. Bench-scale laboratory testwork and a pilot-plant test program are described. The pilot-plant program included production of several tons of products. The thickened talc slurries were very difficult to dewater prior to the drying step. Dewatering difficulties were overcome by use of a high-speed centrifuge. The centrifuge cake was dried either by tray, flash or spray drying. The successful use of one high-grade talc product as titanium dioxide extender in paper is discussed. The talc product has extremely low abrasion values, an important characteristic for minerals used in paper manufacture. It is concluded that this wet process for soft talc ores is capable of producing high-purity talc products for paint, paper, cosmetics and other industrial uses re-quiring very pure soft talc.

Jan 1, 1972

By K. A. Natarajan, M. K. Yelloji Rao

Significance of grinding media wear and its effect on chalcopyrite flotation are discussed. Laboratory marked ball wear tests were conducted grinding chalcopyrite ore and quartzite dry, wet, and with collector added during grinding. The effects of oxygen and nitrogen on ball wear were evaluated by the addition of chalcopyrite mineral while grinding quartzite. The effect of dry and wet grinding on chalcopyrite flotation was also studied. Results show abrasive wear is greater in quartzite grinding than in grinding chalcopyrite. Oxygen increases the corrosive wear of high carbon low alloy steel balls in the presence of chalcopyrite ore. Chalcopyrite flotation was retarded due to wet grinding in the presence of oxygen. Though collector reagent increased the media wear, it improved the flotation of chalcopyrite. Probable electrochemical reactions encountered in a grinding mill are outlined.

Jan 1, 1991

By R. E. Hochscheid

Cyclones installed in three closed- circuit grinding systems were changed from conventional, vertical mounting to horizontal mounting with a favorable improvement in classification efficiency. In two of the installations, apex plugging problems were eliminated because horizontal mounting permit- ted the use of much larger apex orifices. Marked reduction in circulating load was accompanied by greatly reduced maintenance requirements for the cyclone and the cyclone feed pump in one of the installations.

Jan 1, 1988

By John C. Morrisey, Harold M. Ray

With full production from the Casteel Mine in 1987 The Doe Run Company, a wholly owned subsidiary of the Fluor Corporation, encountered a significant increase of copper and iron to the Viburnum Mill. This major change of the lead, zinc, and copper metal ratios in the ore created circuit problems which adversely affected concentrate quality. Recognizing the problem, the company embarked on a metallurgical research program to include laboratory, pilot plant, and plant testing. The program developed an innovative copper prefloat process which both increased copper recovery and significantly improved concentrate quality. The process was tested and first operated at Doe Run's Brushy Creek Mill then installed at the Viburnum Mill in 1992. A brief history of development, plant operating data, and other potential applications for the patented processes will be described in the paper.

Jan 1, 1993

By Vernon R. Shorter, Wayne N. Clark

Introduction Coal is the US's largest indigenous fossil fuel resource and is used to power 57% of this country's electrical generation (NCA, 1986). Congress, however, is focusing its attention on the acid rain issue and public sentiment is leaning toward further curtailments of SO2, NO, and particulates from utility and industrial coal-burning facilities. The Cool Water plant has proven that integrated-gasification-combined-cycle (IGCC) technology can reliably produce economical electrical power while limiting SO2, NOx, and particulates to a rate of only one-tenth of the federal New Source Performance Standards for coal-fired plants. Process water requirements at Cool Water are 40% less than those of a conventional coal-fired utility plant equipped with flue-gas desulfurization units for stack gas scrubbing, thus reducing waste water treatment requirements (Clark and Shorter, 1985). The IGCC technology employed at Cool Water has now been demonstrated to efficiently convert coal to electricity in an environmentally superior fashion. The Cool Water Coal Gasification Program is an unincorporated California association of six partners whose commitment is proving that the integration of gasification with combined cycle power production (IGCC) is commercially viable and environmentally safe. The 120 MW Cool Water plant began commercial production on June 24, 1984. The Program is operating it for a five-year commercial demonstration period. The Program is about halfway through this period. Much of that which was intended to be proven is now fact. In this mid-term assessment, the authors report that the com-

Jan 2, 1987

By Michael J. Mankosa

Carpco has recently evaluated the use of various mineral processing techniques for secondary materials recovery. These applications include recycled foundry sands, plastics and secondary metals. This paper describes different recycling applications and the associated separation solutions. Results from extensive laboratory-and pilot-scale test work in each area are discussed. Industrial installations resulting from this test work will be presented. A detailed description of an industrial installation patented by Carpco for the recovery of plastic and metallics from current waste by-products is presented.

Jan 1, 1997

By L. Meier, M. Dennis, J. Schieffer, K. Murray

"INTRODUCTION Contrary to popular belief, Arizona State Trust land is not public land. All uses of the land must benefit the Trust, a fact that is considered with the review of each application received for sale, lease, or permit. This includes applications for activities ranging from commercial development to recreation. In 1863, the Territory of Arizona was established by an act of Congress. This act reserved sections 16 and 36 in each township to be held in trust for the benefit of the common schools. Later, the Enabling Act of 1910 allowed the Territory of Arizona to prepare for statehood. This act reserved the additional sections 2 and 32 of each township for the common schools and granted another 2,350,000 acres to be held in trust for other beneficiaries. In all, Congress granted the State of Arizona almost 11 million acres. The State was to manage those lands and maximize revenue for 13 separate beneficiaries. To meet this mandate, the State established the Arizona State Land Department (ASLD) in 1915. During fiscal year 2015, the ASLD contributed $136 million to the permanent fund, bringing the total value to over $5.1 billion, through the sale and leasing of the land and natural products which includes minerals. The current inventory of State Trust lands includes 9.2 million acres representing about 12.7% of the State.The ASLD Minerals Section manages the exploration, development, and leasing of mineral products on State Trust land. We are not a regulatory agency, but a department guided by our fiduciary responsibilities to the Trust. Our mineral programs include: Exploration Permits, Mineral Leases, Mineral Material Leases, Geothermal Leases, Oil & Gas Leases, and Special Land Use Permits. INDUSTRIAL MINERALS ON ARIZONA STATE TRUST LAND Industrial minerals fall under the category of either Mineral or Mineral Materials Leases. Common industrial minerals found on Arizona State Trust land include potash, limestone, gypsum, salt, specialty clays, zeolites, crushed stone, and sand and gravel."

Jan 1, 2016