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By Luc Morin

What you don't know won't hurt you! This attitude can get you into trouble when considering your process! When trying to extract the most and the best possible performance from a mineral processing circuit this should be reworded to say: What you don't know about your process will hurt your profits! Today, with the popularity of joint ventures, custom milling contracts and process audits by specialists, not knowing is a formula for trouble! Good Sampling Systems are no longer considered a luxury' Not too long ago the practice of grab sampling was considered acceptable and became the norm. Today, it is rare to hear metallurgists say, "All I need is a trend not a good representative sample. so I'll just grab a sample every few hours." Buyers and sellers of quality products have found that grab sampling leads to poor partnerships'

Jan 1, 1999

By J. D. Vincent

The Henderson mine site is located at Red Mountain on the eastern slope of the Rocky Mountains, approximately 50 miles west of Denver, Colorado. The mill site is on the west slope of the Rockies and mine and mill will be connected by an underground railroad. All designs were for a 30,000 ton per day molybdenite processing plant with provisions for future expansion up to 50,000 ton per day if required. This plan did not just happen, but slowly evolved over the course of about three and one-half years. Many plants cannot afford such a delay, but the Henderson project will take about 10 years from the time it was first discovered until production starts, and these 3 !1 years were well spent in determining the best possible plant site and flowsheet. This paper describes some of the problems and the decisions made in arriving at the final location and flowsheet. The paper does not go into the specific details of how protection of the environment went hand-in-hand with all other project considerations. This particular aspect of the planning has been well-reported on other occasions and considerable information on it is readily available.

Jan 1, 1972

By E. A. Twichell

An entirely new concept in the effective utilization of magnetic, energy has resulted in a major break-through in the design of magnetic separation equipment. One of the first applications of this concept has resulted in the development of a Permanent Magnetic Wet Drum Separator with strength .and operating characteristics equal to Electro Wet Drum Separators. Prior to this development when strength and adjustability were required, electro wet drums were specified even with all their drawbacks. The electros, by nature, are subject to coil failure or burnout, over-heating and loss of strength, high power consumption and generally high maintenance. Now the high strength and the adjustability, formerly the exclusive property of electros, has been engineered into permanent wet drum separators. These units combine maximum field strength in the separation zone with strength adjustment to suit changing conditions. Adjustment can be effected while the drum is in operation without stopping either the feed or the drum.

Jan 1, 1967

By D. Marino

Over the last 20 years, the manufacturing sector of our country has been called upon to comply with ever core stringent environmental standards. The primary metals sector was particularly hard hit early on, to develop the technology, acquire the equipment, and implement the programs to eliminate or reduce the by-products of metal making. To this end, through a combination of technological innovation and extensive capital expenditures, the metals industry has met, and in many cases, exceeded the minimum standards. It is to this escalating cost - liability exposure issue - that Dereco has addressed itself. As we move into the decade of the 90's, the challenge facing the metals industry concerning the environment will be even more difficult than the previous decade. To focus in on one major aspect of legislated environmental regulations, the issue we will address today is; now that the by-products of metal production have been identified, accounted for and collected, how are they to be disposed of? During the course of this presentation, actual data will be presented from our 4 1/4 year on-site experience at J & L Specialty Products

Jan 1, 1992

By B. R. Waples

Sometimes a project is born easy, sometimes a project has a hard time being born. Probably every project can say we had tremendous problems to overcome and they would all be right. This project had all things happen to it. Born easy, a hard time after being born, there were tremendous problems to overcome but here it is, a major copper project, a major operation, and a new source of copper for Mexico and the world market. La caridad is an ore body located in the state of Sonora in northwestern Mexico. It is at an elevation of 1,200 meters above sea level and the nearest major city is Hermosillo, the capital city of Sonora. Hermosillo is located approximately 270 kms (about 168 miles) to the southwest of la caridad. North of la caridad, 130 kms (about 81 miles), is the U.S. border town of Douglas, Arizona, which has a sister city on the Mexican side of the border -Agua Prieta.

Jan 1, 1979

By L. Larrimore

Electric utilities depend heavily on coal as a major fuel source for power generation, annually producing more than 85 million ton'> of ash, boiler slag and FGD (flue gas desulfurization -"scrubber") materials as by-products. Utilities and others who burn coal have traditionally disposed of these by-products in ponds or landfills. However, in the last 10-15 years there has been a greatly increased emphasis on beneficial utilization of these materials by the producers themselves as well as by customers who purchase the by-products. Regulatory, cost and technical performance issues currently impact the use of coal ash and other coal combustion by-products (CCB).

Jan 1, 1997

By Timothy D. Gardner, Christopher Mark

Coal mines in the Illinois Basin have not engaged in pillar recovery for many decades. In large part, this is due to the exceptionally weak nature of much of the roof in the region. But, as room-and-pillar mining is conducted at greater depths, and larger pillars become necessary, recovering them becomes more attractive. Recently a western Kentucky coal mine became the first in recent times to successfully employ full pillar recovery. This paper describes the many challenges that were overcome during the process. From the beginning, the focus was on protecting the miners from roof instability, using cable bolts, mesh, mobile roof supports (MRS), and engineered final stumps. Two short test panels were extracted first, and the results were used to adjust the support pattern and mining sequence. Further adjustments were made based on subsequent experience. To date, seven panels have been recovered without a ground fall injury.

Jul 1, 2023

By Richard J. Lundin

Literature research is an inexpensive, yet effective tool for the direct discovery of ore deposits. Case studies abundantly demonstrate that properties with viable mineralization and *proven reserves have been overlooked, forgotten. or ignored and can be rediscovered by inexpensive literature search techniques Areal studies s as WaIlaby Enterprises Mining District Data Base Program appear to be more effective than traditional commodity studies. The success of such studies depends on the inclusion of Mineral Clairant Questionnaire Data, Mineral Ownership Data, Field Examination Data and the continual updating of all information. Such studies are valuable for proposed or existing Wilderness Area Evaluations.

Jan 1, 1977

By C. L. Jiang

The selective depression of pyrite obtained from Kentucky No.9 seam in coal flotation with various kinds of inorganic and organic chemicals was systematically examined. Most of the organic chemicals tested showed little selectivity in pyrite depression. It was found that both orthophosphate and pyrophosphate were effective for the selective depression of coal pyrite in coal flotation using fuel oil as a collector. At substantially low concentrations of pyrophosphate, the flotation of coal pyrite was completely depressed over a wide pH range, while the coal flotation remained unaffected. The mechanism of the selective depression of pyrite by phosphates has been explained with the help of thermodynamic calculations of iron-phosphate-water systems and zeta potential measurements. It was shown that pyrophosphate reacts strongly with iron ions of pyrite to form stable hydrophilic iron pyrophosphate complexes on pyrite surfaces.

Jan 1, 1998

By C. Roos

"Nearly every input to a mine plan is based on an estimate. The estimates may be from sample data, historical information, models, or personal opinion, but in all cases, these values are simply expected values (means). In real life, we do not get to iterate the exact conditions at our mining operation many times to ensure that that average value is attained. The expected value also tells us nothing about the spread of values that that input might take on. The result is a significant amount of unquantified uncertainty in our mine plans. Unfortunately, it is often too expensive or time consuming to update planning processes and software. This paper presents a proof of concept spreadsheet scheduling tool that can be utilized to incorporate many geologic realizations (simulated models) into the mine scheduling process. While this POC is not intended to be a detailed model of uncertainty, it is to show that there are stepping stones available for mine planners to begin to embrace uncertainty and produce more achievable plans without requiring a significant change in their planning process. INTRODUCTION Mining companies have included quantifying uncertainty, or at least risk, as a requirement of project justification for many years, however many times this process lags behind the traditional mine planning process and the results are rarely used to improve the plan. Nearly every parameter used in a mine plan is an estimate and the mine planning engineer should recognize and even embrace the inherent uncertainty in those parameters and its effect on their forecast results. While many of the uncertainties are beyond the scope of the traditional mine plan (e.g. global market uncertainty, socio-political uncertainty, environmental uncertainty), some uncertainties can, and should, be included in the mine planning process. Many mining engineers have incorporated techniques such as Monte Carlo Simulation or Discrete Element Simulation to understand the range of productivity that can be expected for an operation but most still rely upon one estimated model for what is likely the critical component of technical uncertainty, the geologic resource. Modern geostatistical methods can provide multiple ore body realizations to provide a thorough unbiased “picture” of the geologic uncertainty but most traditional mine planning techniques are not formulated to allow for multiple (100-200) realizations of each material quality/grade parameter. Commercial software companies and research groups are progressing with development of tools that can incorporate geologic uncertainty, and even optimize extraction plans in the uncertain environment. Unfortunately, this author believes that a significant number of mining operations will not be able to adopt these techniques due to the computational requirements of the advanced techniques and the costs associated with implementing proprietary software. In an attempt to encourage mining engineers to embrace the inherent uncertainty in their mine plans, this paper presents a cost-effective alternative that can be developed in-house, at any mine, to schedule mid to long-term mine plans while continuously monitoring the uncertainty in the results. The author hopes that by demonstrating the usefulness of such a system that mining companies will encourage engineers, geologists, and geostatisticians to find ways to incorporate this powerful data into their processes and procedures."

Jan 1, 2017

By T. F. Torries

The primary merit criteria used by the mining industry is internal rate of return (IRR) rather than net present value (NPV) although NPV is favored by academicians. This paper discusses the problems with IRR and NPV and compares the multi-goal nature of decision makers and their need for information with the characteristics of NPV and IRR. Conclusions are that both NPV and IRR are needed for investment ranking, that NPV suffers the same multiple root problem as does IR.R, and the determination of incremental IRR to reach NPV consistent project ranking is misguided in practice.

Jan 1, 1997

By Dave Southworth

After Abe Lee discovered gold (in April 1860) near the site of present-day Leadville, Colorado, he and is group staked nearly all of California Gulch with "speculative claims." They did so in an effort to grab any property that might be potentially profitable. But the plan did not work. New prospectors demanded a miners' meeting, from which arose the official "Bylaws of California Mining District, California Gulch, Arkansas River." These bylaws, adopted on May 12, 1860, established provisions as to the number, size and type of claims that could be filed. Fair laws invited more newcomers. By mid-summer, 5,000 people with tents and wagons were scattered from one end of the gulch to the other.Among the earliest arrivals to the region that spring were Horace Austin Warner Tabor and his wife, Augusta. H.A.W. Tabor, who was to become a pillar in the development of Leadville, arrived at California Gulch during a food shortage. He sacrificed his oxen so that hungry miners could eat. By doing so, he immediately became the friend of many. Augusta established a little store where she sold her baked goods and provided meals. Like most of the men, Horace prospected the surrounding hills. He only did so, however, for a short time. California Gulch yielded more than $5 million in gold during the next five years. By 1866, however, the placer gold was gone and most of the miners had packed up and left. Charles J. Mullen and Cooper Smith, who were grubstaked by a Philadelphian named J. Marshall Paul, found a new, rich lode at the Printer Boy Mine in 1868. It was the first underground gold mine in the Leadville area and marked the transition from surface mining to underground hard rock mining. Its discovery created a new but modest flurry of activity. Heavy black sand covered the region and made gold mining difficult. In 1875 William Stevens and Alvinus Wood decided to have the sand assayed. They discovered that it contained 15 ounces per ton of silver and was rich in carbonate. Stevens and Wood kept their find a secret for nearly two years. When the word spread in late 1877, the silver boom was on. In 1878 prospectors, merchants and others trickled into town from all directions. Dr. David H. Dougan closed his office. in Alma, crossed Mosquito Pass and set up shop in Leadville. Nobody seemed to need a doctor, however, and Dougan sat in his office for 28 days without a customer. On the 29th day he received word that there had been a mining accident and he was needed immediately. -That was the begin¬ning of his illustrious career in Leadville. Dougan was a successful physician, became mayor in 1881 and was later president of the Carbonate National Bank. Leadville was a simple community of log structures in 1878. By June of the following year, however, it had blossomed considerably. According to Cass Carpenter, as of May 1,1879, Leadville had "...19 hotels, 41 lodging houses, 82 drinking saloons, 38 restaurants, 13 wholesale liquor houses, 10 lumber yards, 7 smelting and reduction works, 2 sampling works for testing ores, 12 blacksmith shops, 6 livery stables, 6 jewelry stores, 3 undertakers and 21 gambling houses where all sorts of games are played as openly as the Sunday School sermon is conducted." Additionally, there were 36 brothels. When George E. King and other architects arrived, Leadville took on an air of elegance and sophistication. In sharp contrast to some of the Victorian-style, gingerbread-laced homes in Leadville, its suburbs were comprised of many tenement shacks and plain cabins mixed with a few commercial buildings, many mines and smelters. Mines sprinkled the area east of Leadville like pepper from a pepper shaker. Wherever there was a cluster of mines, a camp usually sprang up. Most were very close together. South of Leadville the giant Arkansas Valley lead smelter sprawled out between Stringtown and Bucktown in an area known as Smelter Valley. Founded in 1879 as the Billing and Eilers Smelter, the Arkansas Valley plant was operated by the American Smelting and Refining Company. Several other smelters operated in the vicin¬ity. In April 1878, Horace Tabor grubstaked prospectors August Rische and George Hook. For $64 worth of supplies and tools, he was guaranteed a one-third interest in their findings. Rische and Hook discovered the Little Pittsburg (often spelled Pittsburgh) Mine and made Tabor an instant millionaire. Tabor once purchased a "salted" mine, the Chrysolite; but instead of considering it a bad deal, he further developed the property and struck rich silver ore. Later, Tabor purchased the Matchless Mine for $117,000, possibly the only investment he made without partners. During its peak years, the Matchless yielded $1 million worth

Jan 1, 1998

By Benjamin Grunauer, Anthony Iannacchione, Taylor DaCanal

"In Pennsylvania’s rich mining history, various forms of room-and-pillar mining have been in use for over 150 years. Longwall mining, introduced in the late 1960s, occupies only the last 60 of those 150 years and now represents the dominant method of extracting coal in the Pittsburgh coalbed. The introduction of longwall mining allowed larger quantities of coal to be extracted in safer and more efficient manners than room-and-pillar mining. However, the associated formation of subsidence basins have elevated both the number and intensity of watersource and surface structure impacts. When these first longwall panels were mined the factors responsible for these impacts were poorly understood and regulations were focused only on surface structures. Today, with over 600 panels mined under a wide range of conditions, these factors are known and regulations have developed to help mitigate water supply and surface structure impacts.The cause and severity of surface effects are thought to be dependent on multiple factors, including the location within the subsidence basin, overburden, panel width, and orientation of the panel. The changing characteristics of over 600 longwall panels mined in the last 60 years are analyzed to determine factors important in subsidence related surface impacts. This study compares the location of the surface impacts with the longwall panel size, overburden, and maximum predicted vertical subsidence. The data shows that changing these characteristics are impacting surface features in a significant manner as measured by the number of company liable reported effects.INTRODUCTIONLongwall mining has occurred in Pennsylvania for over 60 years, and at the current mining rates, longwall mining is expected to continue in the Pennsylvania Pittsburgh Coalbed until the reserves are exhausted. Figure 1 shows all mining that has occurred in the Pittsburgh Coalbed, as well as the area that is left to mine. It is predicted that there are 40 years left of longwall mining on the Pittsburgh Coalbed, under the assumption that 50% of the total 280,000 acres will be mined at the current rate of 3500 acres/year."

Jan 1, 2019

By Jamal Rostami, Tala Tahernia

TBM utilization rate is a component of machine performance prediction and critical for developing a reliable estimate of the construction completion time and cost of the tunnel. Estimation of the utilization rate involves identifying and quantifying the time dedicated to each activity in a tunneling jobsite. Ring building is a common activity in TBM tunneling and takes a large amount of tunnel excavation time when using shielded TBMs. This paper concentrates on the effect of tunnel diameter on the duration of downtimes related to ring building and examines the impact of machine diameter on downtimes. For this purpose, the dependency of segment installation time to segment configuration, and also the diameter of the tunnel was investigated. Furthermore, the ring building time for four tunnels with different sizes of diameters and a variety of ring arrangement were analyzed and the relationship between TBM diameter and segment installation time and consequently TBM utilization was evaluated.

Jun 13, 2021

By Connor Meinke, Shaihroz Khan, Kevin Erwin, Rajiv Chandramohan, Muhammad Usman Siddiqui

High-quality sample selection for metallurgical test work is essential to a geometallurgy study, but the large multidimensional dataset makes sample selection a daunting task, as classifying the dataset while respecting its heterogeneity is difficult. This paper presents a streamlined approach for sample selection, utilizing custom-built tools in Python to standardize the methodology, saving time and costs. This approach uses the cumulative sum method, principal component analysis, and k-means clustering method to elegantly cluster the data and select representative samples. A case study is used to demonstrate the effectiveness of the methodology by selecting 40 samples for flotation test work.

Feb 1, 2024

To generate a most profitable ultimate pit limit is generally the first step in mine design. This paper presents a new graph theory oriented, optimum ultimate pit limit design algorithm which will maximize the total undiscounted net profit. This algorithm performs much better than the well known Lerchs-Grossmann algorithm, in terms of the reduction in computation time and computer memory requirements. This algorithm operates on many directed trees in a graph, where each vertex in a tree represents a block in the mine model. The formation of each directed tree is based more on the ore-waste support concept than the geometry constraints alone. The general procedures of the algorithm, programming considerations and two case study results are discussed in the paper.

Jan 1, 1990

By Mark Kuchta

A new database application for long term production scheduling has been developed for LKAB's Kiruna mine. The scheduler uses a new block data structure whereby the monthly production data for three raw ore products are predetermined on a month-by-month basis for each production area that could be mined within the schedule time horizon. The production schedule is created by assigning the starting dates to the each production area subject to various mining operational constraints such that that the monthly deviations for the production targets are minimized. The system is well integrated into the mine's overall computerized mine planning system.

Jan 1, 2002

By Steven McCutcheon

As most of us have learned through prior and often frustrating experience, anyone proposing to construct a new or expanded mining-ore processing facility must first contend with a rather complex array of environmental laws and permitting regulations administered by a number of different Federal, State and local agencies. At our lost count, there were about 55 federal enactments affecting base and precious metals projects. Applicable State and local laws will usually increase that number significantly. The time and costs associated with complying with all these various regulatory programs usually constitutes one of the major areas of uncertainty in the development of a proposed project. There are many in the mining industry who firmly believe that these environmental regulation and permit programs necessarily causes significant delays and increased costs in the development of a project. This belief, unfortunately, is probably a result of a basic misunderstanding of how the environmental permitting and regulatory system actually works.

Jan 1, 1984

By M. Z. Rashad

The intersection of joint sets and excavation planes leads to removable blocks which can be expected to fall or slide. The amount and cost of supports required to stabilize these blocks of excavation are related to the number and dimensions of key blocks, the mechanical properties of joints and the active forces present. In this work, the application of the block theory in the study of the kinematics and stability of removable blocks is investigated considering any number of sliding faces for some Egyptian limestone quarries.

Jan 1, 1993

By O. A. Velasquez, A. R. Kumar

"Dust generated on underground mechanized coal mining faces is a health and safety hazard. Continuous miners deployed underground usually have an integrated flooded-bed dust scrubber mounted onto the machine that arrests the generated dust from close to the face and cleanses the air around it. However, the impingement screen might get clogged depending on the coal seam being worked. This necessitates the cleaning of the screen which in turn, reduces the overall availability of the scrubber and, hence the continuous miner. A novel non-clogging screen has been developed at the Department of Mining Engineering, University of Kentucky. The proposed impingement screen is built up of three individual aluminum screen units 1.5 mm thick and separated by 3 and 2 mm respectively. The screens have long vertical slits measuring 6 mm. A water spray continuously keeps the screen wet and provides for the filter element to arrest the dust particles. The slits force the dust-laden air to make sharp turns. The dust particles cannot change directions rapidly, impact one of the three screens and are separated out based on their momentum. Preliminary computational fluid dynamics (CFD) models have indicated significant cleaning efficiencies in the respirable range at the expense of much lower pressure drops. Results indicated by CFD models and supported by laboratory experiments have been discussed in this paper.ACKNOWLEDGEMENT The authors acknowledge the National Institute for Occupational Safety and Health (NIOSH) for funding this research. Dr. Thomas Novak, Professor of Mining Engineering, is also acknowledged for his continued support and encouragement. INTRODUCTION Continuous miners are ubiquitous in coal mining around the world. The miners are operated against bling headings, ensuring adequate flow of air at the face could be difficult. The minimum requirement of ventilation airflow quantities at those coal faces are legislated to dilute dust generated to harmless levels. New dust rules promulgated recently have further called for lower exposure levels of personnel working underground (Courtney) (MSHA, 2014) (NIOSH, 2010). Water sprays are also installed at strategic locations and serve as powerful air-movers. The sprays capture some amount of dust generated while cutting. In addition to this, usually, all continuous miners are equipped with a flooded-bed dust scrubber as shown in Figure 1 to capture the dust from close to the extraction drum (Chao & De-sheng, 2000) (Wala, Vytla, Huang, & Taylor, 2008) (Organiscak & Beck, 2010)."

Jan 1, 2018