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By Wei Victor Liu, Omer Faruk Ugurlu, Chengkai Fan, Bei Jiang

Accurate prediction of truck productivity plays a pivotal role in improving the efficiency and profitability of openpit mining operations. This paper proposes a deep neural network (DNN) model to overcome the challenge of predicting truck productivity in openpit mines. The prediction model was built using eight variables and was optimized by considering different train-test split ratios, numbers of hidden layers and neurons, and activation functions. The proposed model’s performance was evaluated using various metrics and compared with other commonly used machine learning algorithms. The results showed that the proposed model outperformed traditional machine learning models by achieving higher prediction accuracy. Moreover, a single-variable sensitivity analysis showed that haul distance is the most influential variable for predicting truck productivity. This study marks a pioneering effort in employing DNN to predict truck productivity in openpit mining, signifying a notable advancement in the field.

Jul 1, 2024

By John Murray, Daniel Ebin, Robert Gould, Yiming Sun, Lizan Gilbert

The Atlanta Plane Train Tunnel West Extension is being constructed at Hartsfield-Jackson Atlanta International Airport using the Sequential Excavation Method (SEM). The tunnel has shallow ground cover and mixed-face conditions and passes underneath the SkyTrain and MARTA stations and airport terminal buildings. It includes a twin tube Bifurcation with a span of over 45 feet and ground cover of 12 feet. A flat roof is being constructed at the Bifurcation to maximize rock cover and minimize surface settlements. This paper focuses on design and construction challenges for the Bifurcation and tunneling beneath the world’s busiest airport, while minimizing impacts to operations.

Dec 1, 2022

By Robert W. Miller

There are many problems faced by ventilation engineers in deep underground mining operations, not the least of which is controlling miner exposure to radon gas and its daughter products. Radon gas is commonly found in uranium mining operations, but may also be present in other deep metal mines. For example, tin mines in England, iron ore mines in Sweden, gold mines in South Africa, and molybdenum mines in the U. S. have potential radon exposures. This is because uranium and accompanying radium ore are ubiquitous to the earth's crust albeit at low levels. The fact that the activity represented by one WL can be caused by a relatively low concentration of radon gas increases the difficulty of control. Since the source of the radon gas is usually widespread throughout a mine, local exhaust ventilation is not a viable control schema. The technique used to control exposure is then dilution ventilation and, in fact, huge amounts of air must be moved in order to reduce potential exposures to an acceptable level. An interesting comparison can be made of ventilation rates in different types of mines. It is estimated in modern coal mines, which are generally acknowledged to have high rates of ventilation, that about eleven tons of air are moved for each ton of ore mined. A typical operating uranium mine may have ventilation flows of 14-15 tons per ton of ore mined. This provides an idea of the scope and importance of ventilation in modern mining operations where radon is a hazard. Further pressure is put on ventilation engineers by the steady downward trend in exposure limits set by national and international standard setting agencies. Much of this tendency toward lowered standards is based upon longitudinal mortality studies of miner populations. Another important factor is the limited number of experienced miners available in the labor pool. For optimum production, it is important to have as many experienced miners underground in each shift as possible. However, the average daily exposure in a U. S. mine must be less than .3 WL to permit the miner to work underground for a full year. The ventilation system then must provide enough uncontaminated air to maintain the WL below the .3 TTL level to maximize production efficiency and minimize personnel turnover and the problems associated with it. Ultimately, the goal of the ventilation engineer and health physicist is to protect the working miner from harmful exposures based upon currently acceptable standards. U. S. Federal regulations require that in uranium mines all active work sites must be monitored every two weeks if they measure above .1 WL. Areas that have .3 WL ratios or higher must be monitored on a weekly basis until five consecutive weekly samples show the level has dropped below .3 WL. Also, exposure records must be kept for all individuals exposed to levels exceeding .3 WL. These requirements provide a strong economic incentive to have a ventilation system that minimizes exposure of any personnel. A good ventilation system requires careful planning, operation and backup in order to fulfill its mission of providing adequate clean air. Its proper operation also requires coordination with production personnel so it can be adapted as new areas in the mine open up and old areas are sealed off. The ultimate indicator of ventilation efficiency to control radon daughter exposure is, of course, monitoring working levels. Historically, this has been done using the Kusnetz, Tsivoglou, and Rolle's methods, among others. These methods all require cumbersome equipment and tedious calculations to obtain the measurements that results in WL. More important, however, they require a significant time lag between sampling and counting, typically 40-90 minutes. This time lag is, in fact, what can cause significant economic losses due to unnecessary downtime as well as high WL exposures. In a typical mining situation, a sampling technician using the Kusnetz method takes a sample, moves to the next location and takes another sample and so on. Forty to ninety minutes after the first sample, the technician will stop, run the activity count on the filter and calculate the WL. The technician may be one-half mile away or several levels removed from where the first sample was taken when it is counted. If the WL ratio is high the technician must then backtrack to the sample position. There are then two options. If the sample area is a working stage, it can be shut down or a second sample can be taken. If the first alternative is chosen; i.e., shutdown and correction of the ventilation, then another sample must be taken, followed by a forty minute wait for results. If the ventilation adjustment didn't correct the problem, then the whole process must be repeated with a minimum of forty-five minutes per sample cycle when using the Kusnetz method. It has been estimated from operating uranium mines that the cost per hour for downtime on a production slope is about $1,50O/hour. The time lag between sampling and resultant data can be very costly. If the second alternative is chosen to verify the first reading, the miners may be unnecessarily exposed to high levels while waiting for the result. Clearly, such a sampling system can be markedly improved by eliminating the excessive time lag between sampling and analysis.

Jan 1, 1981

By M. Downing

This paper gives a brief overview of impacts of coal blending on coal-fired power plants performance and discuses the preliminary results of an on-going study aimed at evaluating the effect of coal properties on the effectiveness, compatibility and thermal reactivity of coal blends. Plant survey studies reported no significant impacts on an existing plant designed for a high rank coal when switched to a blend of low-and high-rank coal. However, slight modification of some aspects (handling, fuel storage/stockpile, transportation, preparation, and general housekeeping) of plant design and operation may be necessary. The preliminary results of an on-going study at the Mineral Industry Research Laboratory shows that more compatible and better blends could be made from coals where ranks are closer than from those where ranks are far apart.

Jan 1, 1997

By Dr. Ing. Hermann Boldt

The Bituminous Coal Mining Industry of the Federal Republic of Germany produces nearly 100 million t/yr of clean coal. The largest coal mining area is the Ruhr District with dimensions of 100 x 40 km (65 x 25 miles). Figure 1: Here is the general administration of Ruhrkohle Akteingesellschaft RAG with its three divisions. Other coal mining areas in Germany are the Saar District and the Aachen District. Ruhrkohle produces 70 million t/yr of clean coal. The company operates 28 mines in the Ruhr District with an average raw coal production of 18000 t/day. Their average mining depth is 831 m (2740 ft.) and the average seam thickness is 177 cm (70 in.). Figure 2: Preparation plant reject is 44.6%. All following production figures will be with reference to raw coal because the raw coal production is the technically relevant number. Mining operations are mainly in non-dipping coal deposits whereby mechanized equipment for flat seams is also applied to deposits dipping up to 45? Coal extraction is done exclusively by the longwall method. Approximately 200 longwall installations are in production at any time. The average longwall length is 221 m (730 ft) ranging between 140 and 290 m (460 ft and 960 ft). The average longwall advance of all operations is 2.8 m/day (8.4 ft per day). Average production

Jan 1, 1977

By Lynn Salvati, Colin LaVassar, Loic Galisson, Joel Theodore, Lynette Sla

"Sound Transit’s University Link and Northgate Link projects will add 6.75 miles (10.9 km) of twin-bored tunnel to Seattle’s light rail system, extending the route north from downtown Seattle. The tunnels are being constructed primarily in glacial soils using pressurized-face tunnel boring machines. Cover over the tunnel alignment varied from 13 feet to over 300 feet (4–91 m). Since the tunnels are located in densely populated urban areas, controlling ground movements and monitoring settlement were essential to success of these projects. Hundreds of geotechnical instruments, including extensometers, surface settlement points, and near-surface settlement points, were used in both projects to monitor settlement. The observed data were compared to settlement predictions made prior to tunneling, and analyses performed to update empirical factors to better estimate settlements. Recommendations for designing efficient and cost-effective settlement monitoring programs are provided based on the review of the monitoring data and analyses.INTRODUCTIONThe paper includes data from Sound Transit’s University Link and Northgate Link projects. These projects will add 6.75 miles of twin-bored tunnel to Seattle’s light rail system. The tunneling for University Link will extend the light rail system from downtown Seattle to the University of Washington. Tunneling from downtown Seattle to the Capitol Hill Station was completed under the U230 contract, and tunneling from the Capitol Hill Station to the University of Washington Station was completed under the U220 contract. The Northgate Link extension will extend the light rail line north of the University of Washington, including approximately 3.5 miles (5.6 km) of twin tunnels between the University of Washington Station and the Maple Leaf Portal and two stations, U District Station and Roosevelt Station. Tunneling for the Northgate Link project is still underway as part of the N125 project. At the time of writing, tunneling from the Maple Leaf Portal to Roosevelt Station has been completed. Therefore data labeled as N125 in this paper only include the portion of the alignment from the Maple Leaf Portal to Roosevelt Station."

Jan 1, 2016

By K. N. Han

The kinetics of gold dissolution in iodide solutions with oxygen in an autoclave was investigated. The leaching process was described by a gas-liquid-solid heterogeneous reaction. The effects of stirring speed, temperature, oxygen partial pressure and lixiviant, concentrations on the overall leaching rate was investigated. It was found that the dissolution of gold could be represented by a heterogeneous chemical reaction. Under the conditions studied, the apparent activation energy ranged from 34.7 to 54.3 kJ/mol. Experimental findings were in good agreement with the kinetic model proposed.

Jan 1, 1998

By R. Merkl

Since the 1940s, decanter centrifuges have become more important for increasingly complex solid-liquid or solid-liquid-liquid separation processes. Sometimes processed industrial or metalliferous minerals are abrasive or are treated with corrosive chemical agents. Traditional mining applications include the processing of coal, gravel and other products, where low-speed decanters, as well as screen bowl decanters and filters, dominate. These have been increasingly replaced by high-speed decanters during the last decade. Decanter centrifuges also started to play a key role in applications such as drilling muds, processing carbonates and separating SX crud in copper platinum ore concentrations of nickel and gold. Communication between machine producers and mineral processing engineers is vital for the right choice of materials and the design of the right decanter centrifuge for the individual process.

Feb 1, 2012

By Matt Bilson, Ritesh Mahajan, Antoni Kuras, Wataru Okada

The Waterview Tunnel comprises twin 2.4 km long 13.1 m internal diameter three lane road tunnels in Auckland, New Zealand. The City Rail Link (CRL) is a 3.45 km long, 6.24 m internal diameter twin rail tunnel underneath Auckland’s city center. This paper presents an overview of the tunnel geometry, segmental lining congurations, geometric constraints, performance criteria and functional reuirements for the large diameter Waterview Tunnels and smaller diameter CRL tunnels. Other key aspects, which include sustainability, innovations, construction performance and practical aspects are discussed and compared. Lessons learnt from these mega tunnelling projects are also presented.

Jun 23, 2024

By C. Bazin, D. Hodouin

Dynamic experiments were performed in a continuous open-circuit 40x40-cm ball mill using a pseudo-random binary sequence of the feed rate and measuring the variations of the discharge particle-size distribution. The impulse response is calculated by a cross-correlation technique. Then a model involving a discrete transferfunction and a time-series stochastic equation is calibrated using maximum likelihood methods. Based on this empirical model, a minimum variance controller with constrained input is designed and its performances are compared, by simulation, to the performances of a conventional PID regulator.

Jan 1, 1987

By H. Colijn

Weight may be defined as the gravitational attraction or earthpull on a body (mass). Thus, from a practical viewpoint, a scale or other form of weighing device is a mans for determining mss. Weighing devices fall into two principal categories: (1) gravimetric; and (2) non-gravimetric or nuclear devices. At present, after many centuries of use, the effect of gravitational force as a meas¬ure of mass in industry and commerce remains by far the most common method for mass (weight) determination. Non-gravimetric methods are just becoming established in the industry. The general trend is toward weighing materials on the Trove. The predominant advantage of continous weighing over batch weighing operations is its ability to handle large tonnages without interrupting the material flow. The accuracy and reliability ability of continuous weighing equipment have improved greatly over the past decade. However, static weighing equipment still outsells continuous weighing equipment, because it is considered more accurate. Batch weighing can also produce a continuous weighed delivery through automation where the process requires it. In caparison with continuous weighing devices, such as belt scales, the batch-type scales have same inherent advantages affecting their accuracy. For example, weighing 300 lbs. per minute on a belt scale may mean that only 3 lbs. will be on the scale mechanism at one time. In order to obtain a scale accuracy of 1/2%, the sensitivity must be at least 1/2% of 3 lbs. or 1/4 oz. On the other hand, a batch scale may discharge a 300 lbs. load every 60 seconds through a timing mechanism. An accuracy of 1/2% can be easily obtained with a sensitivity of 1/2% of 300 lbs. or 24-oz.

Jan 1, 1970

By R. Aliberti, E. Comis, M. Wone

DC Water’s Clean Rivers (DCCR) program involves the construction of approximately 29 km (18 mi) of CSO tunnels in Potomac Group soils in the Washington DC area. Soils include an upper predominantly over-consolidated fine grained plastic material facies (P/A) and lower predominantly coarsegrained facies (PTX). As earth pressure balance (EPB) tunnel boring machines (TBMs) are mainly used in such soils, the correct approach to soil conditioning can make a considerable difference in TBM performance. Soil conditioning laboratory tests are often completed during the planning phase prior to TBM excavation to develop a baseline for soil conditioning, reduce risks, minimize costs, and improve performance. However, only a few basic tests are standardized to date, and conditioning regimes are fine-tuned during the mining phase. The paper illustrates the effort carried out to identify the correct soil conditioning regime for both PA and PTX facies to improve TBM overall performance and reduce ground movement during the excavation of the Northeast Boundary Tunnel (NEBT) in Washington DC.

Dec 1, 2022

By Klaydison Silva, Pedro Silva, Letícia Damet

The current situation of the global mining economy is increasingly focused on the utilization of materials previously discarded in the mining process. The waste from the past, through new processing routes, is gaining new contours for use as high-value-added products. The strategic mine planning process has consequently had to adapt to the new economic reality. In standard scenarios, the focus was primarily on mine sequencing aimed at the highest economic return, with all infrastructure allocated as a necessity of mining. This work aims, in strategic planning, to configure and select the best composition of mining structures. The entire Mine-Plant-Waste-Tailings-Products chain will be considered as a factor in the sequencing of a multimine complex, to achieve the most sustainable utilization of the current mines’ waste. The sequencing is based on concurrent flows of process configurations and capacities, structure sharing, and flexibility of feed types. These factors will guide the sequencing, which will be constrained by components such as waste and tailings disposal rates, lithology feed relationships, and especially product composition through market specifications, all while respecting product shipping capacities.

Feb 22, 2026

By Morgan M. Sears

The stability of gateroad pillars is crucial in deep-cover longwall mining, especially during transitions to wider panel layouts. This study evaluates the transition from a 700-foot to a 1,000-foot panel layout with an inter-panel barrier in a deep-cover longwall mine in Southwestern Virginia to identify a configuration that enhances stability and reduces operational risks. Using the LaModel program, three pillar configurations were simulated to assess their performance based on stress distributions and pillar safety factors. These included the previously used 4-Entry Yield-Abutment-Yield layout, the current 3-Entry Yield-Abutment layout with a 220-ft inter-panel barrier, and the proposed 3-Entry Yield-Yield layout with a 320-ft inter-panel barrier. The findings of this study suggest that the proposed 3-Entry Yield-Yield pillar layout is more effective in managing stresses in deep-cover mining environments. By optimizing pillar placement and improving load management, this layout could positively impact mineworker safety and health. The study underscores the importance of advanced simulation tools in developing innovative solutions to address the challenges of modern longwall mining operations.

Feb 1, 2025

By P. Otto, G. Borm, Th. Dickmann, F. Amberg, R. Giese

Based on many years experience, the well approved Tunnel Seismic Prediction System (TSP) has been substantially enhanced for online geological prognosis in underground construction. The method provides high resolution seismic images of the rock mass ahead of a tunnel face via an array of standard anchor rods. These contain3D-geophones and can routinely be installed during the excavation process. A further outstanding feature of the system is the newly developed high frequency repetitive seismic source which can easily be fixed at a tunnel boring machine. A user-friendly software package enables online data acquisition, processing, 3D-visualization, and interpretation.

Jan 1, 2001

By Stephen R. La Brooy, Tong Deng, Pritam Singh, David M. Muir, A. J. Monhemius, G. W. Warren, E. Peters

The controlled addition of ammonia to cyanide solutions inhibits the leaching of copper minerals but extracts up to 80% Au using as little as 10% of the cyanide compared with conventional cyanidation of copper-gold ores. The solubility of copper minerals and copper speciation in solution is dependent on NH3, CN-, pH and Eh. Rotating disc and electrochemical studies show that gold is leached by a mixed Cu-CN--NH3 complex with either Cu(II) or O2 as oxidant. This complex is slowly oxidised to CuCN and Cu(OH)2 by air.

Jan 1, 1993

We have lived through a period of strong metal pricing during the past eight to 10 years. Copper has been hovering in the range of $3-$4/lb during much of the past eight years, averaging close to $3.30/lb. Gold increased steadily from less than $300/oz levels in the early 2000s, reaching almost $1,890/oz in the third quarter of 2011, before tempering back down to the $1,200-1,400/oz range in 2013. Iron ore prices started to rise in 2005 before the staggering increases experienced in 2008- 2010, reaching almost $190/metric ton in early 2011. During the past four years, iron ore prices have ranged from $100-180/t, averaging approximately $140/t. In the aftermath of such a run, it is perhaps too easy to forget where we have come from: The copper price averaged just 77 cents/lb during the six-year period from 1998 to 2003, and averaged just over $1/lb from 1989 to 1997. The gold price averaged $350/oz during the 10-year period from 1994 to 2003. Even more dramatically, iron ore traded in the range of $10-$15/t between 1985 and 2004. So, we have seen sustained, three- to four-fold increases in copper and gold prices, and 8 to 10-fold increases in iron ore prices.

Mar 1, 2014

By W. Trask

The state of the art in crawler transporters for loads to 3 kt (3300 st) is sufficiently advanced to allow compilation of job cost figures showing the economics of tracked vehicle use under a wide variety of circumstances. Initial costs, cost per ton of capacity, and operational and maintenance expenses are presented. Data is derived from participation by the Neil F. Lampson Co. in more than 3 Mt - km (2.05 million st - mile) of crawler operation during the past 16 years. The effects of economics on future design trends will be examined with particular reference to versatility, portability, and capacity.

Jan 1, 1987

By Jan K. Wolski

The PC computer program PCVENT, version 3.3, for the ventilation network analysis now incorporates a real-time fire simulator. Position of the fire or a source of contamination and the character of the event are input from the keyboard. There are several options of type of fire: heat only, contaminant only, or both with a constant burning rate or with oxygen as the only limiting factor. Airway resistances or fan characteristics can be modified during a fire simulation. This allows testing of various fire suppression strategies. Program application in the analysis of a real mine fire is presented.

Jan 1, 1991

By B. Catalano, D. Ifrim

The Annacis Island Outfall Project includes two TBM bored tunnels with face pressures above 3.5 bar, with an internal diameter of 4.2 metres. This paper discusses the innovative approach to TBM tunnelling and TBM design at the Annacis Outfall Project. The TBM custom design includes a 3.6 m OD core machine manufactured by Herrenknecht and a 5.0 m add-on by the Contractor (Bessac), acting as an extension kit, with optimized gantry design to accommodate for short tunnel drives and quicker launches. This novel design approach produced safety improvement, cost and schedule savings while streamlining logistics of TBM retrieval.

Dec 1, 2022