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By R. Heiser, J. Vendetti, B. P. Connor, E. J. Haas

Health and safety indicators help mine sites predict the likelihood of an event, advance initiatives to control risks, and track progress. Although useful to encourage individuals within the mining companies to work together to identify such indicators, executing risk assessments comes with challenges. Specifically, varying or inaccurate perceptions of risk, in addition to trust and buy-in of a risk management system, contribute to inconsistent levels of participation in risk programs. This paper focuses on one trona mine’s experience in the development and implementation of a field-level risk assessment program to help its organization understand and manage risk to an acceptable level. Through a transformational process of ongoing leadership development, support and communication, Solvay Green River fostered a culture grounded in risk assessment, safety interactions and hazard correction. The application of consistent risk assessment tools was critical to create a participatory workforce that not only talks about safety but actively identifies factors that contribute to hazards and potential incidents. In this paper, reflecting on the mine’s previous process of risk-assessment implementation provides examples of likely barriers that sites may encounter when trying to document and manage risks, as well as a variety of mini case examples that showcase how the organization worked through these barriers to facilitate the identification of leading indicators to ultimately reduce incidents.

Jan 1, 2017

By YUSONG MIAO, DI WU, XIANRONG YAN, YIPING ZHANG, JIE LIN, KEBIN LI

Rock fragmentation size distribution is often used as an important index to account for the blasting effect because it directly affects the subsequent loading, transportation, and secondary crushing. Due to the mismatching of explosive and rock wave impedance, high boulder yield often occurs which affects the blasting effect. In this study, methods of measuring rock acoustic impedance, rock strength point loading, and detonation wave velocity have been used to obtain more accurate input parameters. Then, in the watershed image segmentation technique, the Gates-Gaudin-Schuhmann and Rosin-Rammler distribution functions have been used to analyze and quantitatively describe the rock fragmentation size distribution in the existing muck-pile. Finally, taking the rock properties, explosive performance, blasting parameters, and system characteristic variable into consideration, support vector machine (SVM) regression model has been analyzed on the learning and prediction of samples. The results show that SVM has a good prediction accuracy, high precision, and strong generalization ability. The optimized matching coefficient of rock and explosive wave impedance K ranges from 2.50 to 2.58 times. This study has developed a series of simple, accurate methods for rock properties analysis, detonation wave velocity measurement, and muck-pile model image processing, and a basis for predicting and evaluating rock fragmentation size distribution and optimizing the matching coefficient before carrying out a blasting operation.

Jan 22, 2021

By Michael Day, Paul Kos, Scott Brinton

A hydrogeologic characterization and impact analysis was performed for a proposed quarry at the Hitch Rack Ranch located in the Little Turkey Creek watershed southwest of Colorado Springs, Colorado. Continuous multiple channel tubing, nested piezometers, stream flow measurements, and mapping of known seeps were used to define the three-dimensional potentiometric distribution and areas of groundwater recharge and discharge. Water balance considerations, mass balance calculations, and potentiometric response to earth tides and barometric fluctuations confirmed that the granite fracture system in the ridge area of the proposed quarry has an extremely low bulk hydraulic conductivity resulting in minimal groundwater discharge to sustain the baseflow of Little Turkey Creek. The Little Turkey Creek valley forms the major conduit for groundwater flow exiting from the upper part of watershed underlain by granite. This conclusion has significant implications with respect to mine planning to minimize projected impacts to the hydrologic system and preserve this recharge component to downgradient Denver Basin sedimentary deposits.

By SANDEEP KUMAR JENA

This review work reports the recovery of potassiumfromdifferent rocks and mineral sources. The global demand for potassiumis rising consistently due to the growth of agricultural production. A major portion of the world potassium production is consumed in making of fertiliser; however, other uses include those in pharmaceutical, glass, ceramic, food and detergent industries. The availability of soluble potash minerals (sylvite, kainite and carnallite) in different countries like Canada, USA, Israel and Russia makes them as major potash producers, whereas agricultural-based countries like Liberia, Somalia, Central African Republic, Thailand, Indonesia and Malaysia including India meet their potassium requirement through import only. On the contrary, the availability of huge potassium-bearing rocks/minerals (like nepheline syenite, feldspar, mica, glauconitic sandstone) in these countries containing around 4–17% K2O would be a prospective for commercial production of potassium. The potassium recovery from minerals/rocks is very complicated due to the uniform distribution of potassium throughout the crystal structure. Different physico-chemical separation methods like bioleaching, chemical leaching, flotation and roast leaching have been discussed for the successful recovery of potash values from these rocks/minerals. However, the recovery of potassium from hugely available seawater using the chemical precipitation, solvent extraction,membrane separation and ionic exchangemethods is not cost-effective due to the low concentration of potassium.

Aug 31, 2020

By J. Hupka

Some aspects of kerosene penetration into tar sand have been investigated. The natural tar sand porosity was measured and used to analyze the performance of the hot water process. Subsequently, pretreatment experiments, using 20 kg tar sand samples (Asphalt Ridge and Whiterocks, Utah), and kerosene as a diluent were carried out at the expected summer temperature (26°C) and the expected winter temperature (-14°C). The natural tar sand porosity accessible by diluent has a crucial impact on the reduction of bitumen viscosity, and influences the penetration time required for successful bitumen separation from tar sand by hot water processing. Thus the tar sand porosity is an important variable which determines appropriate operating conditions. Experimental results indicate that diluent penetration into the Asphalt Ridge tar sand (high porosity) is almost complete after 30 min, whereas for the Whiterocks tar sand (low porosity) the penetration process is much slower, and still not complete after 15 hours regardless of the ambient temperature.

Jan 1, 1992

By B. Oraee

Tunnels as any other structures are affected by different loads and stresses. Generally, the loads on tunnels consist of both static and dynamic loads. These loads must both be considered in the tunnel design process. In this paper, the stability state of Jiroft water-transform tunnel is evaluated. Firstly, the in-situ stresses and then using Kirsch?s equations the induced stresses due to static loads in walls and crown of tunnel are calculated. Consequently, the strain caused by probable earthquake without considering the interaction between the concrete lining of tunnel and rock mass using seismic analysis is calculated based on free-field deformation. When the strain is determined, the simplified method of closed-form solution, Wang?s equations and Penzien?s equations are used to estimate the applied forces on the tunnel due to earthquake such as axial force and bending moment on a tunnel section taking into account the interaction of the tunnel concrete lining and rock mass. Results of this study show that the loads applied to the tunnel as a result of earthquake waves can be affect the stability of underground structures, especially long structures such as tunnels.

Jan 1, 2011

By Randall J. Essex

The Construction Institute of the American Society of Civil Engineers recently published the second edition of a 1997 publication on geotechnical baseline reports. The new publication, called Geotechnical Baseline Reports for Construction, Suggested Guidelines, represents a 2-year effort that adds three new chapters to the original publication, as well as capturing practitioner commentary through two industry workshop sessions. The paper will overview the contents of the new publication, particularly the three new chapters.

Jan 1, 2008

By Jamal Rostami, Mark Board, Clayr Alexander, Muthu Vinayak Thyagarajan

In the past several decades, many major equipment manufacturers have ventured into developing new technology for underground hard rock excavation. This includes variety of configurations for full and partial face mobile excavation units. Mining industry prefers machines that can excavate noncircular, flat invert profiles and be able to make tight turns in hard rock. The need to use disc cutters for cutting hard rock has impeded the development of such machines due to the need for gripper system or large mass of a machine to support the force requirements of the disc cutters. Most of the prior attempts have been partially successful and the operations have faced some practical limits and challenges. Among the units that have been successfully used, one can name mobile miner, which was used for rock excavation in some projects. A redesigned mobile miner, called the “Remote Vein Miner,” or RVM, has been developed by Epiroc for underground hard rock mining in Hecla’s Lucky Friday Mine. This equipment potentially opens numerous opportunities for innovation in civil tunneling projects, where the operational flexibility and accessibility of a TBM’s limited tunnel path, design of the profile, and cost are limiting factors. This paper explores the application of the RVM in tunneling projects, its advantages and possible areas of innovation in tunnel planning and design.

Jun 13, 2021

By Shawn McWilliams, Aini Sun, Mike Lichte, Greg Colzani

The Allegheny County Sanitary Authority (ALCOSAN) adopted its Clean Water Plan (CWP) in May 2020, as part of a federal consent decree to comply with the USEPA’s Combined Sewer Overflow (CSO) Control Policy. Planned improvements include constructing a new regional storage/conveyance tunnel system, promoting green infrastructure/ source control, and expanding the treatment plant. Preliminary planning for the tunnel system was completed in October 2020. The Ohio River Tunnel (ORT) project is the first of three tunnel projects that make up the regional tunnel system. The ORT project began final design in 2021. This paper discusses the advancements made to the ORT preliminary planning concepts considering property availability, alignment optimization, tunnel boring machine evaluation, contract packaging and delivery schedules.

Jun 13, 2023

By Robert Giglio

Looking back over the last 150 years or so, it is not hard to see that electricity has been a primary force in shaping human development. It has been a basic ingredient in our industrial revolutions that simultaneously improved the productivity, working and living conditions within our farms, factories, hospitals, offices and homes. Today, it has become an essential part of our daily life and our future. Amazingly, we keep finding new ways to use electricity to make our lives more safe, comfortable and productive. It is a great success story of human ingenuity, achievement and development. Demand for electricity The convenience and value of electricity has not gone unnoticed by consumers. According to the U.S. Department of Energy (DOE) (Energy Information Administration, 2009), electricity is the fastest growing form of energy in the world and during the next 20 years the world will likely consume twice as much of it as it does today. In 2008, almost 20,000 terawatt hours of electricity globally were consumed (Energy Information Administration, 2009). That is enough electricity to light up more than two million baseball stadiums or power more than 11 billion computers continuously for an entire year. The United States has the dubious distinction of be-ing the largest consumer of electricity in the world with enough power to provide each American with more than 3 kW of electricity ? that is about twice the power currently available to Europeans, eight times the power available to the Chinese and more than 25 times the power available to the citizens of India (American Coal Foundation, 2009).

Jan 1, 2009

By John W. Shield

Oxide gold reserves are being rapidly depleted, especially in regions with long histories of gold mining, such as the Black Hills of South Dakota. However, these districts often have substantial additional deposits, where gold is refractory. It is not amenable to traditional cyanide extraction due to the presence of sulfide minerals that encapsulate or otherwise preclude the economic extraction of the gold. Several technologies have been developed to render refractory sulfide deposits amenable to traditional cyanide processing. These include roasting and pressure autoclaving. Unfortunately, these oxidation processes require substantial capital investment and incur significant operating costs. Microorganisms that obtain energy for their life processes by the oxidation of iron sulfides can be used to treat gold-bearing refractory sulfide minerals. As the bacteria convert the sulfide to sulfate, they expose any gold associated with the sulfide matrix. This makes the gold amenable to cyanide extraction.

Jan 1, 1996

By A. Bascetin

It was recently proposed to use the pastefill technology as a surface tailings management method. Surface paste is an economic and safe storage method that respects current environmental regulations. There are many problems related to accidents that occur in conventional tailings damps. In this study, the applicability of the surface paste disposal (SPD) method for a Pb-Zn mine in western Turkey was examined. Density was 3.084 and specific surface area was 0.899 m2/g. The mill tailings have very low plasticity and show characteristics of clays and silts in terms of the Unified Soil Classification System. The particle size distribution of the tailings was 39.2% particles finer than 20 µm. The results of this study showed that the physical and chemical properties of mill tailings make them suitable for SPD.

Feb 23, 2014

By Taghi Sharizadeh, MAURICE SUNKPAL, ELAHEH TALEBI, PEDRAM ROGHANCHI

Excessive heat exposure is among the health and safety hazards that have adverse effects on the mine workers. The very nature of the underground climate makes it a convenient avenue for heat generation and accumulation from several heat sources including autocompression, equipment, and heat from strata. This study investigated the effects of clothing insulation and acclimation on the thermal comfort ofmineworkers who are exposed to heat in underground working environments. Several clothing ensembles have been considered to analyze the effect of the thermal resistance of clothing on the thermal comfort of workers. To investigate the impact of the clothing insulation, the thermal comfort limit of an underground miner was calculated in the form of maximum allowable exposure time for an 8-h shift. Parametric analyses were subsequently performed using an already developed thermal comfort model using MATLAB software. The results demonstrate that clothing insulation has a significant effect on the thermal comfort of mine workers. Increase in the clothing insulation decreases the maximum allowable exposure time of mine workers. This is especially true for the new and non-acclimated workers. Since acclimatized workers can tolerate a higher level of the dehydration and are capable of losing more water by sweat per shift, the maximum allowable exposure time for the acclimated workers are higher than non-acclimated workers. These analyses have shown that acclimated workers can have more continuous work per shift compared with non-acclimated workers. For example, in an environmental condition with clothing that a nonacclimated worker cannot work more than 5 h, an acclimated worker can work a full 8-h shift.

Jun 29, 2020

By W. W. Edgerton

Construction projects may be delivered under one contract package or multiple packages divided by discipline, geographic location, or other characteristics. Dividing the construction into contract bid packages is called contract packaging, and is a vital and strategic aspect of effectively delivering tunneling projects. The process of contract packaging considers many factors, including the type of project, location, and owner?s priorities. This paper describes the key facets of the contract packaging process used recently on several tunnel projects, reports, where possible, on the success of the process, and concludes with recommendations for applying this process to achieve the right contract package.

Jan 1, 2008

By Minerals and Materials Analysis Section

During 1996, US mines produced 319 t (10.26 million or) of gold metal valued at $4 billion. At yearend, mine reserves were estimated to be 4.7 kt (151 million oz) of gold metal. Almost all of the production was from western states. Nevada accounted for about 68% of national production. Information for this article was obtained through annual reports of mining companies, US Geological Survey (USGS) databases and other public sources. Table 1 shows production and reserves by mine. It divides the mines into two categories. These are producing mines whose primary product is gold, and producing mines for which gold is a byproduct or coproduct. The mines listed in Table 1 accounted for more than 98% of US gold production during 1996. Except the Daisy Mine, the table does not include mines that produced less than 31 kg/a (1,000 oz/year). The Daisy Mine started production in December of 1996. Nor does it contain mines whose byproduct concentrate is

Jan 1, 1997

By William A. Gibson, Kenneth P. Neumann

In 1967, development of the Cyprus Thompson Creek molybdenum deposit began near Challis, ID. The first mining claims were staked on an intrusive rock out-crop. Exploration continued for 14 years. In 1978, the decision was made to develop the deposit. In Dec. 1980, approval was received for the environmental impact statement and facilities construction and waste rock removal began. By the middle of 1983, 126 Mt (139 million st) of rock had been removed and all facilities completed. Location The Thompson Creek project is located about 58 km (36 miles) southwest of Challis in Custer County, in south central Idaho. The mine and mill are situated between 2.2 and 2.6 km (7,217 and 8,530 ft) in elevation. The project is located in an isolated area. Surrounded by mountains, it is adjacent to the Sawtooth National Recreation Area. The Salmon river is 8 km (5 miles) south of the project. The project claim block is lo-

Jan 1, 1984

By J. J. Snodgrass

Faults, sandstone channels, and abandoned mine workings present severe safety hazards, disrupt mining, and necessitate costly precautions or discontinuance of operations. In addition to fault detection, mining companies have a need to map discontinuities such as seam thinning and previously mined areas in both longwall and room-and-pillar operations. Initial field tests demonstrated successful generation and propagation of higher order guided wave modes. Theoretical studies indicate potential for improved resolution by sensing small details in the coal seam and roof structure. Controlled-waveform source transducers and specialized detectors are particularly useful to preferentially excite and detect the Love (SH) and Rayleigh-type (P-SV) waves, including the higher frequency modes. The distinct observation of reflections using the transducers in the shear wave mode makes feasible the detection of the water-filled voids.

Jan 4, 1985

By Y. FUJII, E. CHANDA, J. KODAMA, D. FUKUDA, M. NISHIHARA, Y. NAKAYAMA, P. SINKALA

For over 40 years, Mufulira underground copper mine has been recording incidents of rockburst. Laboratory tests and numerical analyses were carried out to understand the rockburst mechanism at the Mufulira mine. Rockburst did not occur in the chain pillars or at the mining face, but mainly in the mining drives along diminishing pillars or ahead of the mining face. RQD suggested that the rock mass in the rockburst areas was relatively intact. Laboratory tests confirmed that the rock at Mufulira mine is very strong and brittle. Elastic stress analyses for the rockburst sites by 3D displacement discontinuity method (DDM) indicated very high stress in the chain pillars and low-stress concentration at the sites of rockburst during the initial mining stages. However, there was no apparent positive correlation between the elastically calculated normal stress values and the occurrences of rockbursts. The 2D elastic FEM analysis was conducted under the concentrated stress by DDM and indicated that some stress increase with face advance for the rockburst in the vicinity of the mining face. However, stress severity indicated almost no increase, and the rockbursts cannot be explained as an instantaneous rock mass failure due to stress increase by mining. Therefore, a creep damage model was proposed to clarify the mechanism of the rockbursts. Cumulative rock damage was evaluated for the edge elements of each sidewall of the mining drives, based on the normal stresses by 3D DDM. The rockburst occurrences were well hindcasted. A method to estimate the volume of the rockburst source was proposed, and a likely result was obtained.

Aug 12, 2022

By Rushikesh Battulwar, Javad Sattarvand, Joseph Seamons, Masoud Zare

In the last decade, new developments took place in the area of indoor positioning (or localization). Since the Global Navigation Satellite System (GNSS) cannot be used in underground mines, other technologies are needed for localization. Positioning and communication options today primarily include Wi-Fi, Bluetooth Low Energy (BLE), Ultra-Wideband (UWB), Radio Frequency Identification Device (RFID), etc. Smartphones and tablets currently have an array of sensors and radios, which can provide valuable information to allow indoor localization via various methods. Where mineworkers could keep smartphones with them, they can be highly effective at enabling localization and navigation. Recent applications of these technologies in underground mines have been thoroughly reviewed and examined for the likelihood of their utility for accurate localization where no other means exist. Some critical challenges and gaps that need to be addressed in future research have been identified.

Sep 5, 2021

By Smart Chika Obiora, Anthony Chukwu

Mining and processing of raw materials is one of the earliest activities of man for survival and development. The products are used for making jewelleries, metal tools, and for exchange of goods and services. However, despite the benefits of mine recoveries, it’s negative and long term effects on the environment and lives remain the point of discussion throughout the world. This study summarizes findings of researches in active/abandoned lead–zinc mines in Enyigba and Ishiagu mining districts including social surveys in the localities surrounding the mines in order to ascertain the effects on the inhabitants. Lead–zinc mining in Enyigba and Ishiagu, southeastern Nigeria has lasted for decades and has affected the socio-economic well-being of the host communities. There are evidences of soil, water, and plants contamination by Pb, Zn, Cd, and Mn in these mining communities. The mining activities also affect the overall social development of the host communities. These effects include retardation in educational development, health care provision, unemployment, and access to potable water supply. Others are rise in poverty level, social amenities, sanitary/hygiene level, high cost of living, and fertility rate. Possible mitigation strategies such as to liaising with relevant government agencies in collaboration with mine owner, mine workers, and host communities can ameliorate these negative effects and promote environmental sustainability.

Feb 24, 2023