Search Documents

By QUANWEN PU, Yonggang Wei, Bo Li

The spent catalyst is one of solid waste resources, which contains precious metals with considerable recovery value. However, due to the different compositions of catalyst, the recovery process is difficult. Most of the catalysts are supported by alumina which has good alkali-soluble properties, while platinum is insoluble in alkali. Platinum is enriched by pressurized alkaline solution which is a kind of hydrometallurgical process. The novelty of this study is the separation of alumina and platinum from the spent catalyst and the enrichment of platinum in the solid phase. In this study, a leaching process using NaOH as leaching agent under high temperature and pressure was employed. The effects of alkali concentration, leaching temperature, leaching time, and liquid–solid ratio on leaching efficiency were investigated. The optimum process conditions were determined as follows: alkali concentration of 240 g/L, temperature of 200℃, pressure of 1.20 MPa, time of 1 h, liquid–solid ratio of 5:1. It was concluded that the leaching rate of alumina can reach 99.69%. The content of platinum increased from 0.1749 to 21.12%, the loss of platinum was 3.39%, and the enrichment ratio of platinum increased by 120.82 times. The leaching kinetics of alumina was studied based on the shrinkage core model. The activation energy of alumina leaching is 19.53 kJ/mol, and the leaching process is controlled by chemical reaction. Pressurized alkali solution can not only efficiently leachate alumina from the spent catalyst and enrich platinum, but also reduce the reaction time and increase reaction rate.

Feb 11, 2022

By Carl E. Williams

During the past two years a computer program called "COPOR," Computerized Open Pit Optimization Routine, has been developed and used for mine planning of several base metal deposits. This routine utilizes a three dimensional computerized block model of an orebody, some economic parameters and operating constraints to locate the mineable or economic limits of the deposit schedule the yearly production from the mine and produce bench by bench ore reserve summaries and maps of the yearly and ultimate pit configurations. The moving cone method is used to perform these functions with a conventional block model. This model is conventional in the sense that each block is assumed to be homogenous; i.e., either ore or waste but not a mixture of the two. Due to the nature of a seam type deposit this approach is not realistic; therefore, revisions have been made to form a new version of the COPOR program. This version has been named "COALOR," Coal Optimization Routine. COALOR contains all of the power of the COPOR program but is equipped to handle the intricacies of coal seam type deposits. The deposit can be composed of a single seam or multiple seams which are horizontal or dipping at any angle. The numerous coal quality values can be incorporated to aid the optimization of the economic pit limits and yearly scheduling.

Jan 1, 1978

By Scott Burchmore, Jason Emery, Michael Melville

This paper presents best practice data management for monitoring of extensometers in Australian underground coal mines. This work is based on the combined experience of the authors and the available literature. The information and ideas presented herein are a culmination of many years of database development founded from mine site-based ground support design, underground inspections, extensometer data management and data analysis. Each author has more than ten years’ experience as a practicing geotechnical engineer at several operating industry wide research project focused on utilizing mechanical extensometer data for data analytics and machine learning. Principal hazard ground control management plans, stipulated in Australian coal mining legislation, outline the mandatory installation of ground monitoring devices during routine mining activities. After 20+ years of data gathering the barrier to implementing modern data analytics remains the challenges imposed by inconsistent data structure and data quality. This inconsistency is still routinely found between sites, companies and mining regions. Through the relatively simple application of a standardized database structure, the potential to shift from simplistic tracking of trigger levels, siloed at individual sites, to an industry standard method for compilation & comparison of monitoring data is enabled.

Jun 25, 2024

By Christopher Nelsen, Daniel Dobbels, R. Zachary Hollenbeck

Recent major floods have inundated Historic Ellicott City, Maryland, resulting in loss of life and property damage. Howard County, Maryland, has developed the Ellicott City Safe and Sound Plan to mitigate the risk of flash flooding in the Historic District, including a proposed stormwater conveyance tunnel. Challenges to overcome include thick zones of saprolite along the alignment, multiple near-surface structures, and minimal rock cover under an active railroad, while minimizing impacts to the public and historic structures. The project will also pursue recognition through the ISI Envision verification process.

Dec 1, 2022

By C. V. Deutsch, D. A. Silva

The geologic modeling of multiple domains is required for the prediction of mineral resources and reserves. In general, explicit methods have wide acceptance among modelers due to the ability to manually add deemed important trends and geological features into the models. As an alternative, implicit geologic modeling techniques are increasingly adopted to reduce professional time requirements. These methods aim for objective, repeatable and flexible models by replacing the manual time-consuming interpretation of sections with the interpolation of signed distance values. These techniques, however, have been developed for the binary case of two domains at a time. The current paper presents an algorithm that extends the binary case to multiple domains. The method is able to transfer large-scale geological features from data to geologic models. A case study illustrates the benefits of the algorithm and practical implementation considerations.

Jan 1, 2016

By J. Bilant, B. Carlson, N. Gow

High Pressure Grinding Roll (HPGR) technology has been evaluated to replace tertiary cone crushing at Coeur Rochester operations (Coeur Rochester, Inc.) as an opportunity to improve silver recovery. In 2016 and 2017, onsite and third-party pilot programs were initiated to evaluate the impact of metallurgical recovery and heap leach performance of crushed product generated by an HPGR. In 2018, Forte Dynamics evaluated the HPGR laboratory metallurgical data from Coeur Rochester and all third parties to develop field-scale leach curves based on new crushing scenarios. The laboratory recovery test work data was consolidated and scaled to field conditions to determine projected heap leach performance. Based on the metallurgical testing conducted, the replacement of current tertiary cone crushers with HPGR technology has the potential to increase Coeur Rochester’s silver recovery rate by 8%, from 61% to 69%, and shorten the overall timing of silver recoveries from 20 years to just over two years. INTRODUCTION The Rochester mine, and associated valley fill heap leach facilities is an open-pit silver and gold mine located in Pershing County, Nevada, approximately 26 miles northeast of the city of Lovelock. In 2017, Rochester produced approximately 4.7M troy oz silver (Ag) and 51k troy oz gold (Au). Ore mined at Rochester is either fed directly to the primary X-Pit crusher, crushed at an in-pit crusher system, or placed directly onto a heap leach pad as run-of-mine (ROM). Both crushing circuits are comprised of three stages of crushing to produce a nominal 3/8” ore. Primary crushing consists of jaw crushing while secondary and tertiary crushing are composed of varying cone crushers. Historical recovery rates of crushed Rochester ore average 61.4% Ag and 95.9% Au over a period of 20 years [1]. These rates were derived from third party verification of in-house metallurgical test results, crusher production and heap leach production results from 1986 through 2004 in a private report for Rochester produced by KD Engineering Co., Inc. Recovery rates are regularly verified by compositing daily samples of ore delivered to each leach pad from the X-pit crusher, in-pit crusher, and/or ROM. A proportionate split of each sample is used to generate monthly composites for metallurgical analysis utilizing column leaching and bottle roll leaching. These tests are run in a manner analogous with production conditions and deliver test results that provide expected heap leach performance. As the Rochester oxide deposit has been mineralogically and metallurgically consistent, the gold and silver recovery trends have also been consistent over the life of the project. In 2016 and 2017, onsite and third-party pilot programs were initiated to evaluate the impact of HPGR technology to metallurgical recovery and heap leach performance of crushed product in an open circuit configuration, as a potential replacement for the currently in place tertiary cone crushers. During these years, HPGR was evaluated in three phases of test work.

Jan 1, 2019

In this paper, the logic and the capabilities of a long term production planning method for open pit mining are presented. The method is the first attempt in obtaining simultaneous solutions to the four interrelated parameters of open pit mining; 1) the mine life, 2) the specific blocks to be mined each year, 3) the amount of ore and waste to be mined each year, and 4) the ultimate pit limits. An efficient cutoff grade can also be obtained through a sensitivity analysis. None of the existing methods can bring such a comprehensive solution to the problem. A production plan for a real life gold deposit is given to illustrate the logic and the capabilities of the method.

Jan 1, 1993

By G. L. Smit

The Buffelsfontein Gold Mining Company is situated in the Klerks-dorp district of the Province of the Transvaal in the Republic of South Africa, approximately 100 miles west of Johannesburg. Gold production commenced in January 1957 and Uranium treatment of residue slimes as a by-product started in July 1957. The mining property is 5435 mining claims in extent, the equivalent of 7,988 acres or 12.5 square miles. The mine was initially exploited by the Pioneer Twin Shaft System, consisting of a 26 feet diameter down-cast shaft and a 22 feet diameter up-cast shaft, sunk in the north-west area of the mine to cater for the hoisting and ventilation requirements for a milling rate of 150,000 tons per month.

Jan 1, 1964

By Neilson Rudd

Many deep well waste disposal. operations have adopted the technology of the petroleum industry but fail to make full use of the knowledge and experience upon which this technology is based. Inexperience in subsurface exploration commonly leads industrial personnel to an over simplified understanding of the complex subsurface rock/fluid environment and overly optimistic "degree of exploration /adequacy of knowledge" ratios. Several fundamental differences between disposal and petroleum production are discussed. In particular, the evolution of understanding of the subsurface in relation to degree of exploration is demonstrated by summarized case histories of such other forms of subsurface fluid exploitation as oil pro¬duction and underground gas storage, tracing subsurface interpretations from the initial exploratory concept to that of fullest development. Evolutionary changes in interpretation and their significance as applied to deep well disposal are stressed.

Jan 1, 1971

By P. D. Rao

Although phosphorus is a very important biogenic element, its concentration in coal is generally low. Phosphorus concentrations typically range from 0.001 % to 0.229% in raw coals of the contiguous 48 states. Some Alaskan coals in the Cook Inlet region contain horizons unusually high in phosphorus. A foot by foot analysis of deep drill core, containing 70 ft. of sub bituminous 'C' coal from the Beluga coal field, Alaska, showed certain increments contained as high as 17.03% P2O5 in the coal ash; 1.01 % P on a moisture-free coal basis. Crandallite has been identified by electron microprobe analyses as a phosphorus numeral in these coals. The authors could quantify calcium, barium, strontium and phosphorus concentrations from the coal attributable to crandallite. These high phosphorus coals provided a unique opportunity to study the association of phosphorus in coals using chemical fractionation for exchangeable cations and acid extractable elements. Since the source of high phosphorous horizons in Cook Inlet coals is attributed to volcanic ash, it is suggested that the profiles of acid extractable phosphorous concentration may be useful for coal seam correlations.

Jan 1, 1992

By T. Gelpe

A digital simulator of classification and grinding circuits is used to evaluate the performances of various flowsheets. For a given flowsheet configuration, unit processes dimensions and operating conditions, the simulator calculates the steady-state values of the process variables. A supervisory algorithm is implemented in the simulator to determine the conditions which meet the required criterion on operation, tonnage and product quality. Calculation illustrations are proposed for the design of wet and dry grinding circuits. The performances of various arrangements of cement clinker and sulphide ore grinding flowsheets are evaluated and discussed.

Jan 1, 1983

By U. K. Custred

Who We Are Farmland Hydro (FHLP) is a Limited Partnership formed by Farmland Industries, the largest U.S. farmers’ cooperative, located in Kansas City, MO, and Norsk Hydro, a large Norwegian company engaged in fertilizer, petroleum and the specialty metals industry. Both of our parent companies have a long history of commitment to the fertilizer industry. This year, Farmland Industry celebrates its 71st year in the business, and Norsk Hydro celebrates its 100th operating year! We employ approximately 300 associates in Central Florida. What We Do Farmland has been active in Hardee County, FL since the 1970’s as a large landowner and citrus grower. We plan to expand this activity into phosphate rock mining. The phosphate rock produced here will be shipped to our nearby chemical fertilizer complex in Polk County, where we produce quality phosphate products - liquid and granular fertilizers. Of the phosphate rock mined, 90% is used to make fertilizer. Other uses include animal feed, vitamins, medicine, light bulbs, soft drinks, film, flame resistant fabric, optical glass, toothpaste, bone china and other consumer products.

Jan 1, 2000

By John L. Halls

Modern business practice dictates that in order to ensure the economic optimization of investment, the size of any investment venture must be such that every increment of capital invested in such a venture yields at least a corporate minimum acceptable rate of return. This practice is based on the premise that alternative investment opportunities capable of yielding the minimum corporate return are immediately available. If a mining corporation is to make the maximum use of its investment funds, any capital investment in a mining property must comply with the above practice. The most important parameter in estimating ore reserves is the cut-off grade which is used to separate material into ore or waste. The cut-off grade is calculated on the basis that material of cut-off grade produces sufficient revenue to cover the estimated costs of mining and processing through to sales, including depreciation and produce a pre-determined profit. Ore reserves so estimated are adequate for determining the magnitude of an orebody but do not provide a sound basis for determining plant size and therefore capital investment in a new property or for expansion consideration on an existing property. From a financial analysis of this one ore reserve it is impossible to ascertain whether each increment of capital investment is providing the minimum acceptable rate of return, Other difficulties associated with the calculation of a cut-off grade including the determination of depreciation and the amount of pre-determined profit to be included in the cut-off grade calculation are outlined in the text. The proposed solution to determine optimum ore reserves and plant size for new properties avoids the complication of calculating a cut-off grade by computing a series of ore inventories using arbitrarily selected cut-off grades. A comparison of the cash flows generated by production from such ore inventories using incremental financial analysis clearly indicates the ore reserve and plant size which will best serve the corporation's investment and metal production goals. Incremental financial analysis of a corporation's operating mines and prospects assists management in assessing the comparative expansion and investment possibilities of each property for increasing or maintaining metal production on a long term basis.

Jan 1, 1969

By W. R. Sharp

The ability to target, delineate, excavate, and produce local resources is essential to the establishment of man's long-term presence in space. Many procedures and equipment utilized to mine resources here on Earth may be directly applicable on the lunar surface, while others may need extensive redefinition and development. This paper compares, for a lunar base, the alternative of burrowing into and below the lunar surface with that of surface mining. A conceptual underground mechanical excavator is presented.

Jan 1, 1991

By R. C. Milici

Historical production data and reserve decline rates can be used both to predict future coal production rates and to estimate when the reserve will be depleted. Reserve estimates inferred herein from historical production data and decline rates are commonly lower than estimates made from geologic data. The latter include significant amounts of lower quality (deeper, thinner, higher sulfur) coal which may be mined when the better deposits are depleted.

Jan 1, 1997

"The paper treats the spatial aspect of mine sequence optimization. This aspect is revealed in the context of determination of the optimum number of cutbacks of an open pit mine. Cutback mining is a dominating method currently in base\precious metal mining and it is based on a pseudo-economic discretization of the pit space by using advanced pit design algorithms. The result of the implementation of such approach of pit design is the generation of pit shells, which need to be grouped into an optimum number of cutbacks for maximization of the project value. A mathematical solution of this problem is developed with the utilization of a combinatorial analysis. The solution provides a multi-variant investigation of the optimum mine sequence with the implementation of an author’s method for production scheduling optimization, which uses the Net Present Value as a criterion for assessing the economic efficiency of mine sequencing. A case study is provided for the conditions of a hypothetical open pit gold mine to illustrate the applicability of the approach. The results obtained reveal the complex nature of the variation of the Net Present Value as a function of the cutback geometry. INTRODUCTION The mine sequence optimization in open pit mining is a procedure that predetermines the efficiency of the production scheduling optimization. From a technological standpoint, the mine sequence optimization deals with two aspects – spatial and time. Each of them plays a tremendously important role in searching for the optimum solution of the open pit design problem. Original results on the time aspect of mine sequence optimization are published by Halatchev [2002]. They reveal a wide range of the Net Present Value (NPV) variation for a multi-variant arrangement of mine sequence over time and using a fixed geometry of the cutbacks, which determines the economic potential of a single open pit mine from a deterministic standpoint. The results show a range of NPV variation up to 30% depending on the stripping ratio of the mine. The effect of this variation is mainly due to the implementation of the mine planning principle of waste deferment in the scheduling optimization and using all theoretically possible variants of mine sequence arrangement by the inclusion of the bench sequences over the Life-Of-Mine (LOM) in the production process."

Jan 1, 2015

By Dong Yang, Jicai Han, Xiaoshuang Guo, Tichang Sun, Zhengyao Li

Straw charcoal was used as a novel reductant in the co-reduction roasting of laterite ore and red mud. The influence of the reductant dosages, co-reduction temperature, and co-reduction time were investigated. Results showed that a powdered ferronickel product of 1.81wt.% nickel and 81.40wt.% iron was obtained under straw charcoal dosage of 15wt.% and roasted at 1250 °C for 80 min. The corresponding recovery of nickel and total iron were 97.21wt.% and 98.87wt.%, respectively. The performance of straw charcoal was also compared to that by the conventional coke reductant. Results showed that ferronickel particles using straw charcoal were larger in size than coke, mainly due to the lower S (0.14wt.%) and ash content (3.80wt.%), which could not hinder the agglomeration of the ferronickel grains, and lower melting point that producing liquid phase and promoting ferronickel particles growth. In addition, the gasification reactivity of straw charcoal is better than that of coke, which is beneficial to the iron oxide reduction and the recovery of iron. To conclude, straw charcoal is a promising reductant for the co-reduction of laterite ore and red mud in coal-deficient areas.

Aug 12, 2021

By D. Anthony, R. A. Williams, R. Raponi

Barrick Gold Corporation in conjunction with SNC Lavalin Engineers and Constructors have developed basic engineering design for counter current decantation thickener (CCD) plants capable of processing 44 000 t/d. To achieve this throughput in a single train, the largest high-rate thickeners installed to date have been utilized in concert with large process slurry and solution transport systems. Process reliability and plant operability and maintainability have been carefully considered in order to develop a practical, yet cost effective design. The design also incorporates the challenges associated with installation of large equipment and structures in a remote location, with a climatically hostile environment, situated in a high seismic activity zone.

Jan 1, 2002

By P. D. Rao

Chemical and physical properties of typical low-rank coal (LRC) ash are significantly different than bituminous coal ash. With the exception of extraneous ash, which is incorporated during mining or is due to ash partings within or between coal seams, LRC ash consists primarily of inherent ash that is bonded into the coal's organic matrix or finely disseminated mineral matter. This paper reviews the nature of LRC ash, both inherent and extraneous, and how this impacts the prospects of washing and utilizing LRCs. A literature review, as well as washability data, proximate and ultimate analyses and ash analysis of 25 Alaskan LRC seams are used as a basis for this discussion. The authors' recent research into the nature and distribution of phosphorous in an Alaskan LRC is also discussed

Jan 1, 1997

The ability to track miners and communicate with them while they work in underground coal mines is important during normal daily operations, and critical in emergency conditions. As was evident during recent incidents at underground coal mines worldwide, communication with miners and the knowledge of their location is of great importance for rescue efforts and the preservation of life. Numerous technologies have been developed, adapted, and deployed to meet tracking requirements of the Mine Improvement and New Emergency Response (MINER) Act. Evaluating the performance of these systems has proven to be difficult for mine operators, system manufacturers, and regulatory agencies. The MINER Act of 2006 requires operators to improve accident preparedness by developing an emergency response plan specific to each mine. With the recent implementation of the provisions of the MINER Act of 2006, all underground coal mines in the United States are subject to the mandates of legislation concerning communication and tracking system installation. As of June 2011, 203 new or revised tracking and/or communication systems had been approved by the Mine Safety and Health Administration (MSHA), with nearly 50 other systems or revisions in the approval process (MSHA, 2011). At that time, the available approved systems for underground coal mine use included these types: ? Leaky Feeder Communication Systems ? Fixed Node-Based Communications and/or Tracking Systems ? Wireless Node-Based Communications and/or Tracking Systems ? Medium Frequency (MF) Communication Systems ? Communication System Peripherals Other types of tracking systems have since been developed and some manufacturers are seeking approval for use in this application. Some of the new products include Through-the-Earth (TTE) systems and various radio frequency (RF) adaptations. New technologies that are currently being developed and deployed in other industrial applications should also be considered, including acoustical, optical, inertial, and hybrid technologies To date, no uniform method has been employed in the industry to effectively compare and evaluate the performance of installed systems. Neither industry operators nor regulatory agencies can accurately assess the capabilities of installed systems in the continuously changing mine environment. There is need for a uniform evaluation method that provides the ability to assess how different systems and technologies perform in various mining applications, and whether they can satisfy the regulatory requirements.

Feb 23, 2014