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By H. Wesley Peirce

Arizona embraces portions of two major western-U.S. physiographic-geologic provinces and a smaller, local one. These exert fundamental control over the geologic framework and associated earth-material resources and potential. The Mogollon Rim diagonally crosses the State and separates the Colorado Plateau Province to the northeast from the Transition Zone and Basin and Range Province to the southwest. More than 90 percent of the population, production of nonfuel minerals, agricultural land, and water resources are in the Basin and Range part of the State. In 1981 Arizona was ranked number one in the Nation with respect to the value ($2.56 billion) of nonfuel-mineral production. About 8.2 percent of this amount ($212.9 million) can be attributed to nonmetallic (industrial) materials. Although a diversity of nonmetallic substances is produced and some are exported, the bulk is utilized within the State and is directly related to market growth. Since 1950 there has been a fourfold increase in Arizona's population, a concomitant twelvefold jump in sand-gravel production (tons), and a twentyfold increase in "stone" production. New industries developed during this time include cement, salt (and storage of liquid petroleum gas products in solution cavities in salt), zeolite, hydrofrac sand, vitrified clay pipe, crushed marble products (teed additive, pool sand, roofing granules, etc.), and "rock" wool. Most of these newer industries serve out-of-State as well as in-State markets. In 1981 at least 225 industrial mineral or rock deposits were being worked to produce about 10 tons of material per Arizona resident per year. In 1980 the relative values of basic industrial minerals produced in the State, by major group, were cement and lime (51.6 percent); gravel (26.5 percent); sand (11.8 percent); stone (4.6 percent); and others (5.5 percent). Detailed knowledge of the nonmetallic rock-and-mineral content of most Arizona ranges and basins is lacking. Exploration opportunities in this sun-belt growth region appear encouraging.

Jan 1, 1987

By S. Pastor, S. Hahn

"As the concept of autonomous haulage systems (AHS) moves from proto-types to production-ready applications, the operating performance of the haul road will become ‘mission critical’ to the overall success of autonomy in mining. Deterioration in road performance will require remediation, human intervention and significant, albeit temporary, changes to operating procedures, to accommodate road maintenance. With autonomous trucks comes the opportunity to reduce road formation and operating width, and therefore generating potentially significantly reductions in stripping ratios and improvements to mine economics, but only if the design of the road, and it’s associated deterioration rate, is predictable and manageable, based both on the materials used to construct the road and the maintenance interventions to be carried out on the road. This paper presents the assessment of a digital photogrammetric approach to the characterization of a mine haul road surfacing, or wearing course material. Design and maintenance parameters for these roads are currently determined from physical particle size distribution (PSD) assessments of ‘in-road’ material. However, this approach does not accommodate the need, nor leverage the benefits from, AHS. The digital imaging approach is assessed in this paper, using two standard digital analysis software tools, together with in-service mine haul road wearing course samples and images which are assessed to determine the applicability and reliability of the approach to deliver a real-time assessment of haul road surfacing conditions and thus to identify the road maintenance interventions required to address deterioration. INTRODUCTION Enhancements in mine road design, construction and management for the past 20 or more years has largely been focused on short-term tactical needs. These improvements have not been matched by advances in the fundamental technologies that underpin mine road design and management, and although the quality of mine roads have probably increased, many of fundamental and longer-term issues have yet to be addressed. With AHS’s evolving from prototype to production applications, any decision to implement these systems in a mine requires a thorough evaluation of impacts, not only operational improvements, but the inter-connectivity of this autonomy technology to other organizational processes. In developing an understanding, the full interactions that may affect autonomous truck behaviour due to changes in various sub-systems or external environments, haul road conditions and operating performance is a key consideration. This is as true in autonomous as well as in conventional mine truck-based hauling systems where the mine haul road network is a critical and vital component of the production process."

Jan 1, 2015

By M. E. Breitrick

Newmont Gold Company began full production in early 1995 at the Carlin East underground mine. The mine is currently producing at the rate of 900 tpd (1.000 stpd). for an annual production of 150.000 ounces. Approximately one hundred twenty five hourly and salary personnel are employed at the project for the estimated six-year mine life. Two mining methods are currently utilized at the mine. Longhole stoping with cemented backfill accounts for 70% of the total mine production. Conventional underhand drift and cemented fill accounts for the balance of the daily tonnage. In December 1996. Newmont purchased a new AC-Eickhoff ET-210 Roadheader. The machine went into service in mid-June of 1997 and is used in both longhole stope topcut development and cut and fill production at a rate of 225 tpd (250 stpd). The Carlin East mine is operated by Newmont Gold Company. The mine is one of four underground gold mines in production in northeastern Nevada owned by Newmont Gold.

Jan 1, 1998

By D. Tahija

"Carbonic acid prepared on-site from carbon dioxide gas is widely used in water treatment and increasingly in some industrial applications. It has not seen extensive use in mineral processing but is an attractive alternative to sulphuric acid for pH control, with the need to counteract high pH levels caused by cemented backfill of particular interest. The fundamental chemistry of carbonate solutions as applied to flotation and flocculation circuits is described as well as plant-scale application. A project to introduce use of carbon dioxide for pH control at the Hecla Greens Creek lead-zinc-silver-gold operation is planned to begin operation in the first half of 2015. INTRODUCTION Flotation pH Control and Backfill Most sulphide flotation circuits are run at pH values ranging from slightly acid to strongly basic, with slightly basic pH the most common. Lead sulphide circuits are typically run at values from 7.5 to 9, with zinc circuits running at higher values of 9.5 to 10.5. This has been the case with ores that produce a natural pH in the circumneutral range, so that the pH needs to be raised. Although lime [Ca(OH)2] is the cheapest reagent in use to raise pH, soda ash (Na2CO3) or caustic soda (NaOH) are also employed where sodium ions in solution are preferred to dissolved calcium, or, in the case of soda ash, the presence of carbonate is desired. The use of soda ash for pH control in lead circuits has been widely recommended for many decades (1). The situation is necessarily different at operations where cemented backfill is used in underground mines (2). Backfill, whether emplaced as rammed paste or pumped slurry, is composed of mill tailings mixed with around 10% Portland or similar cement. When later mining occurs near or adjacent to previously backfilled areas, a considerable amount of old backfill is inevitably mixed with new ore and shipped to the mill. Depending on orebody geometry, mining methods etc., the amount of backfill in mill feed can easily approach 20%, with periods of higher content not unheard of. The presence of so much backfill, with its high cement content, produces results largely indistinguishable from adding a large amount of lime to run-of-mine feed: mill pH in the grinding circuits can range above 11 and high concentrations of calcium ions are present. The need to raise pH disappears; the problem becomes to lower it."

Jan 1, 2015

By Tim Langmaid, Steve Skelhorn, Stephanie Robillard, Allen Mitchell

"The Port Mann Main Water Supply Tunnel project provides a critical water main crossing of the Fraser River for the owner, Greater Vancouver Water District (Metro Vancouver). The project consists of two 60-metre-deep slurry panel shafts and a 1-kilometre-long, 3.5-metre excavated diameter tunnel located near Vancouver, British Columbia, Canada. The initial tunnel lining is a precast concrete steel fiber reinforced gasketed segmental lining. The final lining is a 2.1-metre-diameter welded steel pipe. This paper describes the challenges encountered during tunnel construction and the solutions implemented. Key challenges include earth pressure balance tunnelling at up to 6 bar pressure—the highest to date in Canada—a water-crossing without surface access for the majority of the tunnel drive, ground freezing from a river platform for a critical TBM intervention, and boring through cobbles and boulders in dense glacial till. INTRODUCTION Metro Vancouver supplies drinking water to 18 municipalities, one electoral district and one treaty first nation, serving a population of more than 2.4 million residents. Water is collected in three mountainous watersheds to the north of the Greater Vancouver area, in southwestern British Columbia, Canada. To supply the growing demands of Metro Vancouver’s customers, treated water must be conveyed across two significant water bodies: the Burrard Inlet and the Fraser River. The existing Port Mann water main is one of several key links between the watersheds north of Vancouver and the municipalities south of the Fraser River. The Port Mann Main Water Supply Tunnel (PMMWST) is the first of a series of upgrades, to increase capacity, enhance scour protection, and improve seismic resilience. The new tunnel is 3.5 metres (11.5 ft) in diameter and 1 kilometre (0.6 mi) long. When completed, it will contain a new 2.1 metre (7 ft) diameter steel water main that will help ensure the continued, reliable delivery of drinking water to these municipalities, and will more than double the capacity of the existing 1.2 metre diameter main."

Jan 1, 2016

By V. M. Lepetic

Large tonnages of copper and molybdenum sulfide ore are treated by flotation. Substantial savings could be realized, particularly in high-capacity concentrators, by use of a simplified flotation technique involving lower reagent consumption. Chalcopyrite and molybdenite from some deposits can be floated by use of only a frother as a single flotation reagent; acceptable concentrate grade and recovery can be obtained. Separation of molybdenite from copper sulfides may become simpler and less costly. The genesis of the ore and the ions present in the flotation pulp liquid phase appear to be the major success-determining factors.

Jan 1, 1972

By M. Soderstrom

In a solvent extraction (SX) plant, stage efficiency calculations are used to determine mixer efficiency. With modern extractants and mixing equipment, it is generally taken for granted that stage efficiencies will be above 95%, but this is not always the case. Dependant on mixer/solution conditions, stage efficiencies can occasionally be low, therefore leading to higher reagent usage. Proper methods to identify when stage efficiency performance is below expectations, and ways to identify if it is an equipment or chemical issue are valuable tools for a plant metallurgist. With these tools and skills an on-site metallurgist can more quickly return their SX plant to proper operation. This paper will discuss methods for analyzing stage efficiency, evaluating factors that may affect stage efficiency, and evaluating the impact of stage efficiency on the overall operation.

Jan 1, 2010

By A. Sinha, C. Sawmliana, P. Pal Roy

Using the newly developed and permitted explosive Pentadyne-HP (Gulf Oil Corporation Ltd., Hyderabad), the Blasting Department of the Central Institute of Mining and Fuel Research, Dhanbad experimented at the GDK-5 Incline, RG-1 Area of the Singareni Collieries Company Ltd. (SCCL) to establish one modified angular cut blasting pattern as an alternative to conventional solid blasting in India to obtain longer pull, as well as to achieve at least 40 t of coal in a single blast round for the deployment of diesel load-haul-dump units at the face. This permitted explosive satisfied the statutory requirements of incendivity characteristics applicable to P5 explosives of the regulatory agency Directorate General of Mines Safety (DGMS) of India. The present paper summarizes the development of this new blasting pattern and its possible use in Indian coal mines.

Jan 1, 2010

By V. G. Medina

The 15 000 t/d La Coipa mine initiated operation in July of 1991. The complex consists of a conventional, open-pit mining operation and a mill employing cyanide leaching with Merrill-Crowe gold and silver recovery. The process plant includes a primary crushing circuit, a 15,000 t (live) covered stockpile, a semi-autogenous mill/ball mill/crusher or SABC grinding circuit, a leach circuit, a belt filtration/washing circuit, a zinc precipitation circuit and a "dry" tailing disposal system. The process plant is described in detail with major design considerations used in the selection of the processes and equipment. The unique methodology employed in the disposal of the filtered tailings is also described.

Jan 1, 1992

By A. Martikainen, H. Dougherty

"At the Kemi Mine, a recent expansion into the Surmaoja orebody required an increase in ventilation capacity. A new ventilation shaft was built with two main fans. The installation is near the entrance gate and only 1.7 kilometres from the nearest permanent dwelling. The main fans were first taken into use as exhaust fans in October 2014. Shortly after the fan installation, comments concerning fan noise were received from the neighbours. The first noise measurements were taken at the main fan installation site by Outokumpu personnel in March 2015. Due to higher than expected recorded values, during late June, 2015, a two-week environmental noise study was planned by the engineers and executed by a consultant specialized in noise measurement. The measurement results were analysed and compared to the requirements of the environmental permit and Outokumpu’s factory standards. While the measured values at the nearest dwelling were within the environmental permit limits, high noise values were recorded at the fan station. A second two-week study will be performed after construction of the main-fan heating station has been completed. Actions taken will depend on the outcome. INTRODUCTION The Kemi Mine is a part of the Outokumpu chain of integrated ferrochrome and stainless steel manufacturing in the Kemi-Tornio region in Finland. The mine itself is a large underground operation with a production capacity of 2.7 million tons of ore per annum. It is also the European Union’s only chrome mine, and at present (2015) the mine extracts 2.4 million tons of chrome ore per year. Safety, cost-effectiveness, and environmental friendliness are hallmarks of the Kemi Mine. Environmental impact produced by the operation of the mine is limited due to the insolubility of the oxide chromium ore, the gravity-based and chemical-free enriching process as well as the closed circulation system of the process water which serves both the whole mine and the enrichment process (Outokumpu, 2015). Importance of the environmental impact of the Kemi Mine is amplified by its closeness to the cities of Kemi and Keminmaa with the nearest habitants living less than 2 km away from the mine site. To show the cooperation with residents the Kemi mine organizes special “neighbour days” for the habitants of the areas closest to the mine. Also, information letters are sent to the neighbours, when changes that may affect the neighbours are being planned and executed."

Jan 1, 2016

By Haydn H. Murray

The area from Ohio on the east, Tennessee on the south, and Minnesota on the west: contains some very unique and useful clay deposits. Included are fireclays and plastic clays in Ohio, Kentucky, Indiana, Illinois, and Missouri; flint clays in Kentucky and Missouri; ball clays in Kentuckv and Tennessee; adsorbent clays (fuller's earth) in Missouri, southern Illinois, and Tennessee; and alluvial clays and shales for structural clay products from every state. Unique kaolin clays are known in Minnesota, Missouri, and southern Illinois and halloy-site localities are known in southern Indiana. The geology, physical properties, and uses or potential uses of these midwestern clays are described.

Jan 1, 1980

By R. Flores V.

The Refugio Project is located in the Andes mountains of northern Chile, in the Maricunga Hineral Belt. The Verde, Pancho and Guanaco Au ore bodies have been recognized and are Early Miocene in age. Mineralization consists of fine-grained disseminated gold hosted by dacitic to dioritic subvolcanic porphyries. Alteration comprises massive to veinlet-controlled silicification overprinted on earlier potassic and propylitic alteration and surrounded by later argillic alteration. Geologic relationships suggest that the Refugio ore bodies occur within an Early Tertiary volcano overlying Paleozoic and Mesozoic basement rocks. Geologic reserves at Refugio are approximately 300 million grams (9.7 million ounces) of gold. The Verde deposit contains 185 million tonnes of mineable and leachable ore with an average grade of 0.90 glt Au and is currently in the pre-construction stage after a positive feasibility study. Proven and probable mining reserves at Verde deposit are 101 million tonnes at an average grade of 1.02 glt gold. Additional potential exists at to other deposits within the Refugio property (Pancho and Guanaco) but no reserves have yet been defined due to the limited drilling to date.

Jan 1, 1994

By S. Pollak, J. Rickard

The Long Baseline Neutrino Facility Far Site in Lead, South Dakota is currently under construction and involves drill and blast excavation of the largest and deepest caverns in North America. This paper will review how the geotechnical risks are being managed through careful consideration of excavation sequence, completion of exploratory pilot tunnels, implementation of a robust instrumentation and monitoring program, and validation against the design. Aside from having a cross section of 5,900 square feet and being situated at a depth of one mile, the caverns also employ a unique permanent rock bolt solution which underwent a significant pre-production pull testing program involving varying installation methods and being subject to blast vibrations. The behavior of the schistose rock mass and performance of the ground support are being continually monitored throughout the construction phase.

Jun 13, 2023

By J. A. Delgadillo, C. A. Pérez-Alonso

"Tumbling mills using balls as grinding media are used extensively in the mining and cement industries to produce fine powders; however, it is well known that the process of size reduction is highly energy-intensive. For this reason, much of today’s comminution research is aimed at understanding grinding mechanisms, by estimating power draft and modeling milling circuits using the discrete element method (DEM). DEM predicts individual particle trajectories, the distribution of energy and contact forces at each collision, lifter wear and power draw. This paper presents a prediction of the discharge particle size distribution using three components, mass balance model (sometimes referred to as a population balance model, PBM), impact energy distribution of the mill obtained from the simulation of the charge motion using DEM and breakage characteristics of particles determined from drop-ball tests. DEM simulation of the charge of a tumbling mill was done using the code MinProSim 1.0 to obtain impact spectra at different operative conditions. Then, the population balance model (PBM), based on impact energy distribution, was used to predict the final particle size distribution in a batch mill and compared with experimental data. It is demonstrated that the DEM-PBM approach allows a reliable solution to predict particle size distribution for tumbling mills. Ideally, the model has to predict size distribution for any operational condition and feed characteristic; however, it has been shown that predictions include some degree of error.IntroductionThe discrete element method (DEM) has recently become a powerful numerical tool that can be used to investigate internal mill charge in ball mills. The early work of Cundall and Strack (1979) used DEM to analyze soil as a discrete medium. Later, the method was improved to simulate the operation of tumbling mills and optimize the design in order to increase the efficiency of energy utilization. Also, it is of great interest to relate ore breakage based on impact energy spectra obtained by DEM simulations and the breakage distribution function used in the PBM to predict particle size distribution in tumbling mills.King and Borgeous (1993) broke single particles in an ultra fast impact load cell to compute the phenomenological parameters in a microscopically more detailed population balance model. Kapur et al. (1997) simulated the size spectra of progeny particles produced by impact grinding as a function of the impact energy. Narayanan (1987), Narayanan and Whiten (1988) and Lira and Kavetsky (1990) estimated the energy-dependent breakage distribution function for scaleup and modeling of industrial ball mills."

Jan 1, 2015

By Eric Sitorus, Septian Prahastudhi, Roy William, Wieda Azani

In July 2020, massive slope failure occurred in the southeast corner Grasberg open pit. This was the final episode in the breakthrough of Production Block 2 South (PB2S) of the Grasberg Block Cave to connect to the surface. This breakthrough had been rapidly evolving during the first half of 2020 and occurred as expected with no adverse impacts to safety or operations. To manage and safeguard the exposure to the workforce and operations, numerous hazards were identified and anticipated. The failure of the sill pillar between the open pit and PB2S cave was identified as the main area of interest and was closely watched during the failure process. This paper reviews the systematic approach developed to convert monitoring data into information around the collapse of the GBC PB2S cave sill pillar. The data that was interpreted consisted of micro-seismic, piezometric, ground-based radar and observational inspections. Geological structures on the boundary of the PB2S cave were clearly involved in the breakthrough process. As the cave propagation reached these structures and triggered instability, the resulting acceleration and breakdown were clearly shown by IBIS radar units associated with high movement in the slope. The focus of this paper is on the evolution of changes seen in the micro-seismic data and how it was used to understand the rapidly changing conditions of the sill pillar. The seismic parameters evaluated were event distribution, Es/Ep value, and the seismic moment tensor inversion. The changes of breakthrough indication seen in these parameters were substantiated by Shear Wave Splitting (SWS) analysis that showed a close correlation with the fractured zone above the PB2S cave as indicated by the increasing anisotropy.

Jan 1, 2022

By I. A. Tinto

Labrador City is located in the southwestern portion of Newfoundland-Labrador, approximately 965 kilometers north-east of Montreal. The mine and beneficiation complex of the Iron Ore Company of Canada, known as the Carol Project, is situated 535 metres above sea level in a climatic region characterized by cold winters and short, cool summers. History The iron Ore Company of Canada commenced work in the area in 1949, however, it was not until 1958 that the decision was made to proceed with mining operations. The ore body consists of Specular Hematite (Fe203) and Magnetite (Fe304) with small quantities of Limonite and Geothite. The average grade of the ore bodies is 39% iron.

Jan 1, 1985

By T. W. Camm

The Bureau of Mines conducts studies of the economic impacts of regulations on federal lands. These studies are part of the Bureau Potential Supply Analysis (PSA) program. To meet the needs of these studies, a methodology was developed to estimate operating and capital costs for a mineral deposit given its tonnage, grade, and depth. The format for the cost models in this study was developed at the Bureau's Western Field Operations Center (WFOC), Spokane, W. A., for studies of known and undiscovered resources on Federal lands. These cost models are described in a Bureau publication by Camm (1991).

Jan 1, 1993

By Jogeshwara Sahu, Sapan Kumar Kandi, SANDEEP KUMAR JENA, Sachida Nanda Sahu, Sarada Prasad Das

The present article reports the recovery of potassium from mica scrap using carbide lime waste and NaCl. The acid leaching of mica [4 M H2SO4 at 90 °C] can recover a maximum of 25% potassium. However, in the chlorination roasting (with CLW and NaCl) water leaching process, it was possible to recover potassium to the tune of 94% [900 °C, 50 min roasting; mica:CLW:NaCl 1:0.75:1]. The formation of water-soluble phase like sylvite (KCl) and water-insoluble phases like anorthite ( CaAl2Si2O8) and nepheline ( NaAlSiO4) confirms the complete breakdown of the mica crystal structure. The extraction mechanism proceeds with the formation of a transition state followed by the release of potassium as KCl. The characterisation studies using ICP-OES, XRD, FTIR and FESEM support the proposed extraction mechanism. The salt produced by the evaporation of roast-leached liquor confirms the presence of sylvite and halite only, which can be separated to get the fertiliser grade KCl.

Sep 29, 2021

By W. C. Lacy

Traditionally Australia has been a leader in underground mining methods with world standards being established at Mount Isa, Broken Hill, Kalgoorlie, and Mount Lyell. With decline in higher-grade reserves and discovery of a multitude of near-surface oxide gold de-posits attention has shifted to bulk mining of low-grade gold ores by open pit methods, heap leaching and activated carbon recovery of gold values. The paper examines historical change in mining philosophy and the economic effects of isolation.

Jan 1, 1993

By Yi Luo, FENGLIANG WU

Explosions and fires originated from longwall gob due to the formation of methane-air mixture have been a severe threat to coal miner’s lives.Many numerical studies on coalmine fire and explosion hazards have focused on the airflow in roadways and mine gobs. However, most of these studies isolate the gob from its surrounding roadways, and the network analysis and the CFD method are applied independently tomodel the two classes of airflows. This approach greatly limits the ability of simulatingmine ventilation flow, especially unable to consider the effects of gob boundary conditions on air exchange between the gob and the surrounding airways. An innovative finite tube method (FTM) is developed to couple the one-dimensional mine ventilation network (MVN) and the 2D/3D gob flow field (GFF). In FTM, GFF is discretized into a finite number of flow tubes each of which is formed by any two adjacent stream lines. These tubes, representing the gob’s field flow, connect the MVN into a new coupling network. To solve the coupling model betweenMVN and GFF, an iterative solution technique is developed inwhich the MVN analysis is used to evaluate the boundary pressures for GFF simulation and in turn the FTM feeds the GFF results back to the coupling network. Based on the FTM approach, a model for gas migration in gob has been established for delineating the hazard zones of explosive methane concentration and spontaneous combustion. A computer program is developed to implement the FTM simulation. An illustrative example with five flow tubes representing the GFF is created to verify the stability and convergence of the FTM solution process. A simulation example also indicates that the accuracy of FTM is improved by 12% compared with previous method. Results of an application case show that the program is capable of quantitatively evaluating the gob’s risk zones prone for spontaneous combustion and gas explosion as well as performing risk analysis for various ventilation scenarios.

Jul 10, 2020