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By John G. Kuhm

INTRODUCTION The goal of any development drilling program is the drilling of the exact number of holes necessary to adequately determine grade and dimensions of an orebody, no more and no less. This cost of development drilling represents a large part of the total development budget. Any technique which eliminates unnecessary drilling costs produces beneficial results, both to the company and to the person who can claim the savings. This high development cost factor has produced a quantity of research to develop techniques, for efficient control of drilling programs. Recent mining literature is full of articles describing methods for measuring and increasing the effectiveness of these expensive projects. The method described in this paper was developed during the latter part of a major development drilling project at the Christmas Mine of Inspiration Consolidated Copper Company in Gila County, Arizona. It was used to test the need for drilling individual holes but could be expanded to control an entire project. This technique was used at Christmas as a practical means for evaluating adequacy of drilling on an individual hole basis, and it was possible to eliminate several previously approved holes. Application of this method involves an evaluation of geological conditions present and a good bit of common sense. Projects involving large disseminated, rather homogeneous orebodies of the porphyry-copper type would be the most likely candidate for application of the technique. Discontinuous orebodies would not be amenable to this technique. The method is based on the measurement of the linear correlation between the spatial distribution of two sets of data. The Pearson product-moment correlation coefficient is used. This is a standard statistic commonly used to measure linear correlation between two sets of data. The statistical significance of the correlation coefficient at a 95% confidence level is the main criterion for controlling the project. For purposes of reference we will call our technique the "correlation method" in this paper.

Jan 1, 1971

By J. E. Dreier, R. E. Scheffel, A. Guzman

"This paper outlines a comprehensive, cost-effective testing program for the acid-ferric sulfate heap leaching of oxide, supergene and primary copper ores. It is based on extensive experience in copper heap leaching and uses the many technological advances in the field developed over the past several decades. The approach described requires firstly a detailed resource evaluation, then a hydrodynamic characterization of representative samples and, finally, a focused metallurgical testing program. The principles communicated here can be applied to other acid leachable minerals. The program varies considerably from conventional testing in its disciplined, orderly, step-by-step approach, its application of hydrological and chemical principles to leaching, and its reliance on fewer, more tightly controlled column tests. The purpose of the test program is to optimize the financial, time and other resources devoted to the program, while minimizing the financial risks to the development company or companies and the project funding providers. IntroductionThe major goal of any process development testing program should be the successful implementation of the project. With respect to heap leaching, the metallurgical testing program plays a critical role in the larger objective, as described in Scheffel (2013, 2014). McNulty’s series of papers (1998, 2004, 2014) confirm that the success of any project is directly proportional to the extent and quality of the testing program on which the process is designed.Therefore, a key development objective is to conduct a well-focused metallurgical test program. While the primary focus of this paper is copper, the acid leaching of any substance would benefit from a similar approach.This paper addresses primarily the sulfate system, which is compatible with the bioleaching of sulfide minerals. Nicol et al. (2011) described the advantages of the chloride leaching of copper sulfide minerals. United States patents Nos. US 2009/0173188 A1, US 8,597,933 B2 and US2015/0232963 A1, assigned to BHP Chile Inc. and BHP Billiton S.A. Ltd, describe methods for both the oxidative and nonoxidative leaching of primary and secondary copper sulfides. Reyes (2013) and Ipinza and Flaquer (2014) described commercial applications of chloride-based heap leaching. The testing disciplines discussed in this paper will also apply to the development of an acidic chloride leaching system."

Jan 1, 2016

By Andrea Brickey, RICHARD AMOAKO, Akshay Chowdu

Production forecasts derived from the medium-term schedule represent the best path forward for underground mining operations to achieve corporate and operational goals. Unforeseen circumstances, such as equipment breakdown, can cause significant deviations from established production forecasts in the short term. Such situations require timely mitigation of the effects of the deviations in order to stay as close as possible to the medium-term plan. This paper presents a deterministic mathematical formulation for short-term scheduling that addresses this challenge. The formulation is able to make up for deficits resulting from operational disruptions by minimizing deviations from medium-term production goals and mediumterm activity start dates. We demonstrate this in a case study by simulating disruptions involving reduction in ore extraction capacity and development advance rate. Aside from the rescheduling capability, this formulation can help mine planners conduct analysis on the impact of various disruptions on the schedule. The formulation can help identify those conditions or disruptions that are more detrimental to the achievement of forecast targets, or otherwise. The formulation also affords mine planners the flexibility to prioritize one production goal over the other, depending on operational conditions at the mine. In the future, we seek to incorporate in the formulation respirable dust, diesel particulate matter, and ventilation constraints in order to create more realistic schedules and enhance miners’ health and safety.

Sep 6, 2023

By Jie Zhang, Xi Zhang, Yu Wang, Wei Zhao

The study proposes a novel reagent scheme where adding a small amount of citric acid (CA) significantly improves the depression effect of sodium silicate on calcite and fluorite. The flotation results suggest optimal concentrations for CA and sodium silicate, achieving nearly complete depression of the minerals. Theoretical analysis indicates that CA dissolves calcium ions on the mineral surface, enhancing the adsorption of sodium silicate and preventing collector adsorption.

Mar 27, 2022

By Jim V. Rouse

Adverse water-quality impacts of uranium mining and milling activities on both surface- and ground-water resources in the Grants Mineral Belt have recently been documented.1 In some cases, the impacts resulted in violation of existing regulations and license conditions and have endangered public health. Unfortunately, industry-sponsored ground-water monitoring programs do not adequately record the actual impacts of mining and milling on ground-water quality.

Jan 1, 1976

By E. L. Montgomery

Salar basins in the Andean Highlands of Northern Chile contain ground-water resources which could be used to satisfy requirements for the mineral industry in the region. Salars occur in arid zones; average precipitation is about 200 millimeters per year at altitudes of about 4,000 meters, and average annual evaporation is two meters or more. The salar basins are hydrogeologic sinks where water flows from recharge areas at the margins of the basins to discharge areas at the salt encrusted salar at the lowest point of the basin floor. Groundwater circulation occurs principally in the alluvial and fractured bedrock aquifers. Results of pumping tests for exploration and production water wells indicate a range in maximum sustained pumping yield of 62 to 126 liters per second, and where abundantly fractured, ignimbrite comprises the most prolific aquifer. Chemical quality of groundwater is good. Long-term pumping from properly located production wells in the salar basins would result in lowering of groundwater levels and salvage of water in areas where groundwater is lost via evaporation.

Jan 1, 1986

By Erwan Yap, Brian Mangogna, Craig Romrell, Jeff McKay, Weishi Mang, Andrea Deml, Adam Steimel, Justin Dix

The Doe Run Company (Doe Run), a global supplier of lead (Pb), copper (Cu) and zinc (Zn) concentrates, and lead metal alloys, installed an enterprise expert control system— termed as Digital One—on the company’s Pb, Cu and Zn circuits at its Buick Mill in December 2022. Digital One was developed with Metso and deploys Metso’s product, VisioFroth™. This automated system is now running and optimizing the flotation processes for all three circuits (Pb, Zn and Cu), all plant air and methyl isobutyl carbinol (MIBC). In addition, Digital One also controls a second, newly built, modern flotation reagent system. Digital One also paves the way for automation and expert control of the entire mill, integrating grinding, thickening and filtration. Digital One is digitally immersed in a universal distributed control system (DCS); therefore, today’s mineral processing plants may be upgraded to it or designed around it. This presentation will explore the plant design and operation of this technology at the Doe Run Buick Mill.

Feb 1, 2024

By Jue Kou, Hongda Xu, Tichang Sun, Shichao Wu, Wenli Han

To investigate the effect of simultaneous change in particle size of raw materials (including ore, reductant, and dephosphorization agent) on the direct reduction process of high-phosphorus oolitic hematite, the experimental research of method with direct reduction and magnetic separation was conducted to investigate the effect of simultaneous change in particle size of raw materials on the final reduction products in the form of mineral composition, reduction speed, metallic iron particle morphology, phosphorus distribution, and powdery reduction iron. The results revealed that under the same conditions of reduction temperature, the raw material particle size affects the mineral composition of the final reduction product, the coarser the raw material particle size, the slower the reduction speed, the lower the metallization rate, and the larger the final metallic iron particle size formed. Under the same conditions of raw material particle size, the reduction temperature affects the mineral composition of the final reduction product, the higher the reduction temperature, the faster the reduction speed, the higher the metallization rate, and the larger the size of metallic iron particles within a certain reduction time. Neither the raw material particle size nor reduction temperature affects the form of phosphorus present in the reduction product. Both the raw material particle size and reduction temperature affect the grade of powdery reduction iron to a less extent, but affect the recovery rate and phosphorus content significantly. At the same reduction temperature, the recovery of powdery reduction iron and phosphorus content gradually decreases with the increase in raw material particle size. For the same raw material particle size, the recovery of powdery reduction iron gradually increases, and the phosphorus content gradually decreases with the increase in the reduction temperature. The results identified the effect of simultaneous changes in particle size of raw materials on the direct reduction process of high-phosphorus oolitic hematite and provide a basis for the selection of raw material particle size for the industrial application.

Dec 20, 2022

By R. Bruce Tippin

because of the mineral's high monetary value and the spotty occurrence of free gold in the deposit. Setting up a plant sampling procedure by simply applying the usual statistical sampling theory was questionable. Two sampling concepts were considered in the sampling study: o a sufficient number of assays can be taken such that the average determined from these individual samples represents a known quantity of ore. o a sufficient weight of sample can be taken such that when assayed it represents a known quantity of ore. The test program included evaluation of sampling techniques, sample preparation and analytical methods. The overall sampling program is depicted in Figure 2.

Jan 1, 1985

By MEHMET KIZIL, PETER KNIGHTS, ROYAL REA

A 1/20 scale experimental dozer push test rig was designed and constructed to quantify the expected production rates (loose cubic metres per hour) for dozers operating in hard rock bulk push applications. The particle size distribution of the material employed in the test rig was modelled on a fragmented muckpile representative of that for a typical surface copper/gold mine overburden. A commercially available road base material was found to be highly representative of site conditions. Buckingham Pi theory was applied to mathematically develop factors for scaling up dozer productivity parameters, including blade loads and push times. Dozer production rates were investigated for various dozing distances and slope angles. A series of instantaneous productivity curves were produced which are applicable for use in hard rock dozer push operations. Currently, it is difficult to estimate dozer push productivity in hard rock environments due to dozer productivity correction factors that are empirical in nature and provide only discrete, end-point values for a range of operating conditions. The productivity curves produced demonstrate that dozer productivity declines rapidly over the range of 10 m to 40 m. As such, it is recommended that efficient bulk dozing operations in hard rock mining blocks should not exceed 40 m dozing distance. Further testing of muckpile conditions with increased clay and moisture content would be beneficial in order to better understand and quantify the effects of cohesion on hard rock dozer push productivity.

Nov 23, 2021

By William Gleason

"Caterpillar is the largest manufacturer of mining equipment in the world. In hundreds of surface mines around the globe, Caterpillar’s flagship 793 haul trucks can be found moving material for copper, coal, gold, iron ore and other mines. Likewise, its iconic yellow bulldozers are at mine sites the world over — the company recently announced the sale of its 40,000th large dozer. And since its acquisition of Bucyrus in 2011, Caterpillar has positioned itself to become a worldwide leader in the underground mining sector as well.But don’t think that the company is resting on its reputation. As evidence of its commitment to the global mining sector, as well as its confidence in the future of mining, Caterpillar invited mining trade press, including Mining Engineering, to its Tinaja Hills Training Center near Tucson, AZ in November to introduce the latest editions to its mining portfolio. The two-day event focused mostly on the newest electric drive haul trucks, the Cat 796 AC, which will operate in the 326-t (360-st) class, and the 798 AC in the 360 t (400 st) weight class.Caterpillar representatives also spoke about new offerings in the underground space as well as the newest version of the D11 large dozer.“It has been 10 years since we launched the F Series,” Jean Savage, Caterpillar’s vice president, surface mining and technology said. “Since then, we have been on a journey to serve our mining customers and we wanted to have trucks in every application. Today, we are launching two new trucks that will allow us to fill out our portfolio.”While Caterpillar previously offered the broadest range of off-highway haul trucks to the mining industry, it was noticeably absent from the 326-t (360- st) and 360-t (400-st) weight classes."

Dec 1, 2018

By J. F. Burr, D. Snyder, W. Calder

This paper provides a determination of the equivalent level of protection of the international standards relative to similar criteria used by the U.S. Mine Safety and Health Administration (MSHA) to approve two-fault intrinsically safe (IS) stand-alone equipment. U.S. mining law requires such a determination for MSHA to use alternatives to existing standards. The primary issue is to demonstrate that the international standards for equipment evaluation will provide at least the same level of protection for miners as the document currently used by MSHA.

Jan 1, 2018

By J. F. Burr, D. Snyder, W. Calder

This paper provides a determination of the equivalent level of protection of the international standards relative to similar criteria used by the U.S. Mine Safety and Health Administration (MSHA) to approve two-fault intrinsically safe (IS) stand-alone equipment. U.S. mining law requires such a determination for MSHA to use alternatives to existing standards. The primary issue is to demonstrate that the international standards for equipment evaluation will provide at least the same level of protection for miners as the document currently used by MSHA.

Jan 1, 2017

By S. Rukhaiyar, M. Ramulu, G. Pradeep, P. K. Singh, P. B. Choudhury

The drill and blast method is the most prominent rock excavation method used in mining and civil engineering projects. The ground vibration is the most undesirable effect of the blasting and needs to be controlled. The blasts are designed so that ground vibration at nearby structures must remain under the prescribed limit. Various empirical blast vibration attenuation models have been presented to estimate the ground vibration for designing purposes. These models assume ground vibration as a function of distance and maximum charge per delay. United States Bureau of Mines (USBM) model is most commonly used for the blast design. However, the uncertainty associated with these models is seldom characterized, thus diminishing its reliability. The probabilistic Bayesian approach associated with the Monte Carlo method can easily quantify uncertainties associated with the model and its parameters. Thirty-three blast vibration observation data from a granite quarry in Kerala, India, is used to estimate the probability distribution of model parameters. Markov Chain Monte Carlo (MCMC) approach is used for sampling 12,000 samples for obtaining the posterior distribution of parameters. The uncertainty associated with model parameters is quantified from the posterior distribution, and this is further used to estimate the credible and prediction limits of the model. The point estimate of the most optimum value of the parameter is estimated using maximum-aposteriori or MAP estimate. The model parameters are also obtained using the commonly used least-square error method, which is a maximum likelihood estimation or MLE approach. It has been observed that the accuracy of the model obtained using both MAP and MLE approach is almost equal. However, the MAP estimate as per Bayesian probabilistic analysis has the added advantage that it can estimate the uncertainty of parameters as well as the model, which is not possible using the MLE approach.

Sep 27, 2021

By Shiwei Wang, Ziwen Li, Chenhu Zhang, Peng Chen, Chengyong Wang

Accurate prediction of the partition coefficients in coal gravity separation is key to improving the preparation efficiency of coal and promoting its clean utilization. In China, the approximate formula method (AFM) has been applied to the calculation of coal gravity separation partition coefficients for decades, but its accuracy is limited. To improve the accuracy of the predicted partition coefficients, and thus the product yield of coal preparation plants, the present study proposes a modified hyperbolic tangent model to derive direct calculation formulas for the heavy medium and water medium separation partition coefficients. Four groups of coal samples were used to verify the accuracy of the direct formulas, and their predictions were compared with those of the AFM. The results showed that the partition coefficients and partition curves predicted by the direct formulas were closer to the actual values than those predicted by the AFM. Further, when the cleaned coal ash content was basically the same, the cleaned coal yield predicted by the direct formula was lower than that predicted by the AFM, and was also closer to the actual value. These results demonstrate that the direct formula produces more accurate results compared to the conventional AFM. As this formula has a reasonable theoretical basis, is simple to apply, and produces accurate results, it is expected to help improve the design and management level of coal preparation plants.

Oct 15, 2022

By K. KAKLIS, O. SAUBI, Z. Agioutantis, R. JAMISOLA

Three-point bending (TPB) tests were conducted on prismatic Nestos marble (Greece) specimens. The specimens were instrumented with piezoelectric sensors, and comprehensive recordings of acoustic emission (AE) signals were obtained. Machine learning in the form of artificial neural networks (ANNs) was then applied in an effort to investigate whether specimen load evolution can be predicted as a function of AE signals. A number of ANN models were developed, and the optimum model was selected based on the highest coefficient of determination (CoD) value as well as the lowest root mean square error (RMSE) value that was calculated for each model. The best performing ANN model exhibits accuracy above 99% with an RMSE value below 4%. It can be concluded that ANNs can potentially be applied to predict rock behavior under load especially when such loads lead to failure.

Sep 7, 2022

By E. J. Owen, S. Cherotich, V. T. McLemore

Breccia pipes are vertical pipe-like columns of rocks that provide conduits for fluid flow and open spaces for mineral precipitation, hence are focus areas for exploration. In the Gallinas Mountains, Lincoln County, New Mexico, there is recorded production of Cu, Pb, Ag, F, Fe, REE (as bastnäsite), and Au from 1902 to 1980, but no production reported from the breccia pipes. Previous studies described the occurrence of REE in breccia pipes, but their transportation and deposition controls are still unclear. The aim of this research is to characterize the magmatic-hydrothermal breccia pipes in order to understand the geochemical and physical conditions of deposition of REE and gold in the breccia pipes found in the Gallinas Mountains. There are more than 20 exposed breccia pipes that form a NE-trending belt about 3–5 kilometers, mostly gray-brown and consist of angular- to sub-rounded rock fragments, some host high concentrations of REE (80,500 ppm total REE) and Au (175 ppb). Preliminary studies suggest they are magmatic and intruded into the host rock and, subsequently, hydrothermal fluids precipitated F-REE and Au along the edges of some breccia pipes. More studies are underway to test this hypothesis.

Feb 1, 2023

By Ashis Bhattacherjee, Bijay Mihir Kunar

A literature review on quantitative analysis of mine safety studies revealed that investigators use a wide range of statistical techniques for the analysis of mine injury data. Researchers have addressed the various issues of accident causation and prevention through analysis of mine injury data collected from mines. These studies are generally based on historical accident/injury data without considering the injured person/population at risk. In this paper, a public health approach, based on scientific methods of epidemiology, is presented to address mine safety issues. Epidemiology is the scientific study of disease and injury patterns among populations in time and space. Originally, epidemiology was concerned with epidemics of communicable diseases. Then it was extended to non-communicable diseases. Safety researchers found that epidemiologic methods are the best tools for injury research, because the occurrences of injury and the occurrences of disease are quite similar. As a result, some researchers started applying this concept to injury research. This paper presents some of the techniques used in epidemiologic studies and illustrates the application of a case-control study design to evaluate the role of some risk factors associated with injuries in underground coal mines. In this study, the injured persons were identified and, simultaneously, interviews were conducted to find the significant risk factors responsible for occupational injuries in coal mines.

Jan 1, 2011

By Robert C. Freas

While on the surface limestone marketing may appear mundane, it has continued to provide a series of challenges beyond the realm normally envisioned with this industry. This paper presents a case history of a mature and well-established quarry company that has attempted to keep pace with an ever-changing economy. It examines the impact of socio- economic and technological factors on the company's marketing efforts, and looks at the role of both short and long range planning. The realities which have had to be faced and how product requirements have been kept in balance with production restrictions are also discussed.

Jan 1, 1981

By Mohammed Sakr

The empirical relationship between torque measured during installation and pile capacity has gained a wide acceptance in the helical pile industry in the last few decades. This paper presents a theoretical model developed to estimate torsional resistance of cohesive soils to helical pile installation. The proposed torsional resistance model was then used to establish torque factor, Kt, a factor that is widely used in the industry. The results of the study indicated that the Kt factor is a function of the load path (i.e. tension or compression), pile geometry and soil properties. The assessed Kt factors in tension and compression were validated by the results of 74 installation records and full-scale helical pile load tests. A parametric study was also performed to qualitatively assess the relative importance of different parameters that affect the Kt factors.

Aug 1, 2013