Abstract: There is an increasing requirement for mines to meet a certain minimum criteria for sustainability within the context of the physical environment, ecosystem and socio-economic system in which they are located. The mining industry has wrestled to develop methods for assessing the ‘sustainability’ value of a mining project and indicators of ‘sustainability success’. A methodology for the evaluation of sustainability of a mining project using the Multiple Accounts Analysis (MAA) system was developed. The MAA is a platform for engagement of stakeholders and for the assessment of site-specific alternatives based on both qualitative and quantitative indicators of

Abstract: Iron ore tailings from beneficiation plant are solid wastes.Its utilization is an interesting issue cared by the whole society.According to features of high-silicon iron ore tailings from dressing plants in Tangshan area,some new ways and their applications of utilizing tailings as building material are introduced.

Abstract: The “functional performance equation for ball milling” was first presented in 1988. It has now been used successfully in a substantial number of mineral-processing plants. This powerful, yet simple, tool provides a new level of understanding of closed circuit grinding. It shows how grinding circuit efficiency is really comprised of two distinct efficiencies. It demonstrates how circuit production rate is a factor of these two efficiencies, energy input and the grindability of the ore. And it links circuit performance to design and operating variables that can be manipulated. Thus, it provides an effective strategy for making plant improvements. This paper covers the derivation and industrial validation of this equation. As part of a grinding process engineering system that also incorporates suitable metrics and process control, all operators can use this tool to improve and manage the performance of their grinding operations with clarity and confidence. (McIvor, 1984). The same engineering procedures that were used to select cyclones and pumps for a new application could be used to make cyclone and pump changes in an existing plant to manipulate the internal size distributions and related mass flows (the circulating load) of a closed grinding circuit. Combining this new-found knowledge with the critical and well-known relationship between grinding circuit productivity and the circulating load ratio (for example, see the references by Davis, 1925, and Gaudin, 1939) led to the realization that there existed a valuable opportunity to improve grinding circuit efficiency. An observed poor (low) circulating-load ratio could be increased by suitable pump and cyclone changes — thus increasing circuit efficiency. This, in turn, could be verified by Bond work index analysis and the related operating cost savings used to justify the cost of the plant improvements. But, although the circulating load effect published by Davis and Gaudin was broadly known, it was not at all understood. The question was: “Why is circuit performance so drastically affected by circulating load ratio?” The literature, including Davis’s and Gaudin’s, offered no explanation. It was while examining size-distribution data from two plants that had about the same circuit product sizes (P80s) but different circulating load ratios — one extremely low (<150 percent) and one extremely high (>500 percent) — that a revelation occurred. Seeing very different size distributions into and out of the two ball mills, the reason for the huge difference in circuit efficiencies shown by the Davis relationship suddenly became clear. With the low circulating load, the ball mill was relatively full of fines (P80 product size or finer material). Therefore, most of the grinding energy of the mill was being wasted. With the high circulating load, the mill was relatively full of coarse material and relatively little MIN_047_051.indd 47 10/18/06 9:59:59 AM 48 novEMbEr 2006 Mining EnginEEring of its energy was being wasted. The effect that circulating load has on circuit efficiency was related to the corresponding proportions of coarse versus fine material in the mill. Subsequent investigations showed that the arithmetic average of the percentage of “coarse” material (the circuit P80 being the typical cut off size) in the mill feed and discharge size distributions yields a meaningful, quantitative measure of the percentage of coarse material in the mill (McIvor, 1988). The validation of this and subsequent aspects of this new method for improving plant grinding performance is the subject of this paper. Derivation of the functional performance equation Circuit “classification system efficiency” and “effective mill power” defined. With reference to the standard closed grinding circuit shown in Fig. 1, the above-described observations lead to the following definition of ball mill circuit “classification system efficiency” (CSEff). It is the percentage of “coarse” material in the ball mill, relative to the target grind size, typically the circuit target P80. The “coarse” material is targeted for further grinding, while the “fines” have reached target product size or finer. It follows that the circuit CSEff is also the relative percentage of mill power being expended on “coarse” material versus “fines.” Similar to the efficiency of a drive component, such as a motor, it is the percentage of the mill energy that is delivered and used for the intended purpose. It is noteworthy that a higher CSEff also means less overgrinding of “fines” and, therefore, improved recovery of valuable minerals in downstream processes such as flotation (McIvor and Finch, 1991). The CSEff can be calculated as the arithmetic average of “coarse” material in the ball mill feed and discharge. It represents the net outcome of all the factors that create the size distributions of the material entering and leaving the mill. There are two key factors in this regard. The first is the classifier performance. It controls the percentage of “fines” versus “coarse” material reporting to the cyclone underflow/mill feed. The second factor is the length of time in the mill. This determines the amount of “fines” that accumulate during each pass through the mill. Low circulating load equates to long mill residence time and the buildup of fines. Another factor that plays a role is the breakage characteristic (the tendency to create fines during a breakage event) of the ore. But it is the combination of classifier performance and circulating load ratio that is the key to determining the net outcome of circuit performance in terms of CSEff. The “effective mill power” (EMP) can then be defined relative to the total mill power (TMP). EMP is the percentage of total mill power draw delivered to the “coarse” ore and is defined as EMP = TMP x CSEff (1) The ball mill circuit functional performance equation. A practical measure of a given circuit’s productivity (as used by Davis, for example) is the relative production rate of new product (PRNP) size material (in Davis’s case, -106 μm or -150 mesh). The production of new product (or “fines”) comes about from the application of power to the “coarse” material. This is the “effective mill power” (EMP) as defined above. So it can be stated that the production rate of “fines” in the circuit equals the specific grinding rate of “coarse” material (SGRC), i.e., per unit energy applied to it, times the amount of power being applied to it (the “effective mill power”). This can be written as PRNP = EMP x SGRC (2) Substituting EMP from Eq. (1) gives PRNP = TMP x CSEff x SGRC (3) The specific grinding rate of coarse material (SGRC) will depend on two factors, the grindability of the ore (the opposite of its resistance to size reduction) and the efficiency of usage of the energy that is applied to the coarse particles. This efficiency will be determined by factors, such as grinding ball sizing and percent solids in the mill. A standardized lab grindability test can be carried out on the coarse material that is being fed to the mill. Then, the ratio of the plant mill specific grinding rate (SGRC) of coarse material to the standardized lab mill-grinding rate (LabGr) of coarse material will be a relative measure of the efficiency of usage of this energy that is being applied to coarse material (the efficiency of the mill grinding environment). So, to incorporate the material’s grindability into Eq. (3), divide and multiply the specific grinding rate of coarse particles by the measured lab grindability of the same material as follows PRNP = TMP x CSEff x SGRC/LabGr x LabGr (4) One can then define the ratio of plant to lab grinding rates as the relative “ball mill grinding efficiency” (BMGEff) as follows SGRC/LabGr = BMGEff (5) Substituting in Eq. (4) gives the “functional performance equation” for ball milling PRNP = TMP x CSEff x LabGr x BMGEff (6) Equation (6) demonstrates that the production rate of the circuit is dependent on four factors. One is the power draw of the mill. Another is the nature of the ore in terms Figure 1 Simplified schematic of the Selbaie ball mill circuit. MIN_047_051.indd 48 10/18/06 10:00:00 AM Mining EnginEEring novEMbEr 2006 49 of its grindability. It also shows that there is not just one “efficiency” but two active and distinct efficiencies involved in determining the circuit production rate. These are the “classification system efficiency” of the circuit, or the percentage of the mill energy used on coarse particles, and the “ball mill grinding efficiency,” which characterizes how well the energy being applied to the coarse particles is being utilized. The functional performance equation was developed and named as an outcome of “value analysis and engineering” (Miles, 1972) of closed circuit grinding. Given the information outlined in the introduction to this paper, this process identified that the purpose of the grinding circuit is to generate as much new product with as little energy as possible. It then identified that the purpose of the equipment (pumps, cyclones and mill) was twofold: first, classification to maximize the use of energy on coarse material, and secondly, the efficient size reduction of the coarse material by effective use of this energy. Industrial use and validation The following are some examples from mineral-processing plants for which permission was granted to publish the data. They are intended to show how the functional performance equation is a tool that can be used to better understand and effectively improve grinding-circuit performance, as well as to demonstrate how the validity of this equation has been tested and assured. Sample calculation and dimensional analysis. Table 1 presents data from the Les Mines Selbaie grinding circuit Survey No. 2, which was performed with the crusher fines stream off on a standard closed ball-milling circuit (Fig. 1). From the data, the work index performance of the circuit is calculated as follows: • The

Abstract: The traditional design of mining often uses 2D to express 3D geology environment and the layout of laneway.That restricts the efficiency and the rationality of the mining design.The article emphasize on how to apply the 3D visualization technology to the aided design of mining efficiently and also put forward the idea of building 3D parametric aided design support system of mining.

Abstract: The effect that isopropyl xanthogen ethyl formate is synthesized with isopropyl xanthate under differ condition has been studied.Floatation experiment in Wushan show that isopropyl xanthogen ethyl formate has higher recovery ratio and higher grade in concentration ores than xanthate when they are used as copper sulfide collector.

Abstract: The structure and property of bentonite were showed.Several modifying methods of bentonite were introduced.The adsorption effects of organic pollutants from wastewater by natural bentonite and several kinds of modified bentonite were summarized.The influences of pH,initial concentrations and adsorbent amounts etc.on the adsorption of bentonite were discussed.Moreover,the adsorption mechanisms and rules were dissertated,and applying prospect of bentonite in wastewater treatment were also presented.

Abstract: The coal resource is a precious wealth of the country,and can not rebirth.So mining and using of coal resource should be reasonable in order to increase the recovery.In this article,I analyse the profits for enterprise and country by increasing recovery and talk about some viewpoints on how to increase recovery at the basis of the present condition of our country's recovery.

Abstract: According to slope characteristic of Qidashan Iron Ore Mine and its major influencing factor,exposits forecasting theory and judging method on destroyed slope of Qidashan,and suggests mature and effective administration means in slope prevention.

Abstract: The Catastrophe Theory Evaluation Method is used to assess the economic profit productivity of a high output high efficiency mine.The results of assessment conform to actual status of the mine.Therefore,the results of assessment can be taken as basis for technical reconstruction of the mine.

Abstract: With the increase of mining depth,swell-up of tunnel bottom plate in underground coalmine occurs often that is a danger for safety of mining activities.The reasons of swell-up and its form are discussed,and the precautions against swell-up are explained.

Abstract: Principle,characteristic and application area about disposal methods of heavy metal wastewater are described in the paperWith structure and capability of sepiolite,the current research development in disposing heavy metal wastewater is discussed,and its exploitation is analyzed

Abstract: The composition of mine wastewater is complicated and the harmfulness is great,among the rest the acid mine drainage is the worst contaminative.This paper has summarized the development and the current situation of acid mine drainage treatments;it has introduced neutralization method,constructed wetland and microorganism method in detail.

Abstract: Compared with sinter,pellet possesses advantages such as low investment,low operation cost,high quality,high blast furnace techno-economic indexes,energy saving and environment-kindness.Increment of pellet ratio in BF burden can bring remarkable comprehensive benefits.

Abstract: With rapid development of market economy in China and to meet synchronization of engineering design with international mode,the"Engineering,Procurement,Construction"emerges as the times require that brings vitality to market economy.The contents,advantages and attention-calling issues of EPC are discussed.