| Industrial grade is an index to calculate industrial reserves at a given mining block, so it is a concept closely associating with the geological attribute of mine. In addition, the industrial grade of ore mining is an essentially critical grade between the industrial ore with economic value and the low-grade ore without economic value, therefore, industrial grade has explicit economic meaning. In fact, the change of industrial grade inevitably makes the ore grade and ore quantity changing correspondingly, even with the rate of recovery, dilution rate, concentration recovery ratio of ore changing more or less. This shows, industrial grade is a directly influence factor for the ore grade and ore quantity, which influences the concentrate ore’ quantity. What is more, the quantity of concentrate ore is an important means of mine enterprise to gain profit, and the price of concentrate ore is also an important factor for the economic benefit of mine enterprises. So, the dynamics of mineral products price determines the ore industrial grade should also take on dynamic.To sum up, industrial grade is a dynamic concept, which is highly relvent with income, cost, geological grade, dilution rate, loss rate and so on, it is actually in the mining process associated with those indexs closely, so it is a highly nonlinear function, which would change with time and space complicatedly, in view of this, it is difficulty to try to build its fuction or expressions. Therefore, the grade optimization needs the help of intelligent algorithms or dynamic programming methods. Among them, genetic algorithm, neural network and particle swarm algorithm has been widely used in mining engineering.From a long-term point of view, industrial grade is also affected by the production technology and opreation environment. With the development of mining and milling of ore technology, it is possible to reduce the ore grade in the process of ore mine, which means industrial grade should be adjusted accordingly. Mine production cost of iron ore enterprises also affects industrial grade too, if cost high, it is necessary to reduce direct cost in the process of mining and milling, which means that high grade ore rises esources should be used as much as possible, so industrial grade should be increased correspondingly. Conversely, industrial grade should be reduced accordingly. Optimization of industrial grade is based on the basic assumptions, which is that ore enterprises would gain reasonable profit or maximum profit from the ore productions, but the iron ore price and production cost of ore is the most important two indexes affecting the economic profit of mining enterprises, in fact, industrial grade has a certain sensitivity to concentrate prices and the cost of management of mining enterprises. Therefore, industrial grade is a complex system includes mining enterprises economic technology and geological properties. The research methods should adopte with system engineering method.Industrial grade has the obvious technical and economic significance, so its grade value of accounting requires of the economics principles to establish the calculate model. This grade is the critical grade between the low-grade ore and the table of mine, if the economic principle of "incremental revenue equals with marginal cost" used, the marginal grade of low-grade ore mining is the industrial grade, so the calculating model based on this principle is called "static model", which is according to static compare between marginal cost and marginal revenue; if the economic principles of "economics people pursue the economic profit maximization" used, the optimal model of the industrial grade is to be establish based on the industrial grade system analysis, and this model is called dynamic model, just because of the dynamic of model parameters and its solving process. An important premise of the method is distribution of geological grade based on the sample data to be known well, which is very useful to determine the relation between the industrial grade and ore quantity, and all constraint conditions could be clear.Iron mine of Jinshandian is a typical underground mine, and this iron ore enterprise is selected as a case study of industrial grade optimazation based on grade optimal theory in this paper. For this company, there are some essential information about production management, geological properties of Iron mine, the main technical parameters and its cost structure a required for optimal industrial grade, therefore, this paper gives a detailed analysis of the cost management structure of this enterprise, and calculate the unit variable cost and fixed cost and their annual growth rate based on2009-2011historic data, and analyzes those results. In addition, the price of iron ore is a very important indicator of business environment, so this paper analyzes the the mechanism of price of the Wuhan Iron and Steel Group, and compared the price trend characteristics between imported ore and domestic ore. All those basic analysis is to be a good foundation for optimize the industrial grade.Accoring to the actual production data of Jinshandian iron mine and other related information, this paper gives the calculation results, such as the basic industrial grade, economic grade and profit grade. Among them, the concept of profit grade is put forward by the writer according to the calculating connotation. According to the latest national standard classification of solid resources reserves, economic grade can be used as industrial grade because of the consistency of practical significance. The results show that the industrial grade optimization result is reasonable, which means that this method has a certain practical value. But it is also some obvious shortcomings, such as iron ore price has large influence, and some indexs inclding the relevant investment loans index, expected profit index and the investment recovery period index are difficult to accurately calculate. Even so, this method still can not deny its practical significance, because its economic meaning is very clear, and the calculation results is ocular, as well as its additional grade corresponds with thinking mode of input and output, what is more, this result is consistent with the industry standard and actual production. Besides, this paper gives another dynamic model according to the profit of net present value maximizing principle. This model has its obvious advantages comparing with that static model, because it considers with the dynamic of the capital of time value and the enterprise business operation, this conclusion has been confirmed by this paper’research. Therefore, the industrial grade optimization decision system should be established by this paper based on the dynamic optimization model.In short, industrial grade optimization in underground mining is a system engineering, which involves many factors including geological, production technology and economic benefit etc,. This paper studies on industrial grade of iron ore mining in uderground, and comprehensive, systematically summarizes the basic theories and method, meanwhile, this paper is also mixed together or integrated of intelligent algorithms for optimial modeling about the indexs of ore mine. According to those, this paper studies as a case of the iron ore of Jinshandian, and comprehensive analyzes of this mine enterprise grade management related data about production management and its operation, then, the optimization model is built, and the ndustrial grade is optimizated by this model. Lastly, a decision support system of industrial grade optimization is to be constructed based on this model. The main results are as follows:(1)This paper put forwards the industrial grade optimization of static model in underground mine. The static industrial grade model is derivated by the model of economic grade about low-grade ore utilization in open pit mine at home and abroad, and it combines with the production technical conditions in the underground iron ore, what is more, it applies economics principle of " marginal revenue equals with marginal cost, then, calculated some grade indexs, such as the basic industrial grade to maintain the enterprise daily operation, and the economic grade, which can compensate for investment loans besides the normal operation, and the profit grade, which can ensures the normal production and investment loans compensating, and in particularly, a reasonable profit expectation can be gained. Among them,"profit grade" is a word putfowarded by the writer according to the economic significance of the grade. The calculation result shows that this result accords with the actual production and operation of this iron mine.(2) Proposes a dynamic model of industrial grade optimization in underground iron mine. This paper gives the dynamic model of industrial grade optimization based on the principle of "Lane", which can carry out the target of NPV of profit maximam, and describes the algorithm of this model and its basic steps. In the case study, after systematic and comprehensive analysis of various constraints about industrial grade in Jinshandian iron mine in the process of production management, the mathematical model is built to optimizate the industrial grade of this enterprise, and calculation results are also obtained by genetic algorithm, then the analysis of results shows the reasonablities of the model. (3) Systematic comparison the static models with the dynamic models. In order to scientific evaluation optimal models of industrial grade, this paper compares the static with the dynamic models, and compares the calculation results from two types of models based on the data of Jinshandian Iron mine with a lot of assumption conditions. Analysis of comparison results shows that the dynamic model has more advantages than the static model. This conclusion provides the basis of construction the decision supporting system for the industrial grade optimzation.(4) Studies the forcasting technology of Concentrate production cost. Optimization of industrial grade must involve the production cost indexs of mine enterprises, in which the unit concentrate variable cost has important influence on the optimization models and the optimization results. However, the mine enterprises could generally not forcast the cost, because of the leading of industrial grade decision-making, and the lag of the cost accounting, as well as the cost varieties diversity and complexity, so that the unit variable cost prediction of mining enterprises concentrate. In order to optimization of industrial grade, this paper presents the theoretical arithmetic about the unit concentrate variable cost, and provides the theory basis for quantifying this index.(5) Carries out calculation of the dynamic optimization model by genetic algorithm, based on the analysis of industrial grade system. In Jinshandian Iron Mine, the average industrial grade is40.35%in2011, geological grade is correspondingly41.23%, while the industrial reserves is totally2948000tons of annual plan. In addition, the average recovery rate is0.807, the dilution rate is0.248, the concentration recovery ratio is0.8188, and the grade of iron concentrate is65%, after calculation, the results of Optimization:industrial grade is23.52%, and the output of iron concentrate is1206200tons, while the utilization ratio of low-grade ore is58.74%. Comparison of actual iron concentrate output of115.35in2011, the actual production is increased by53700tons, and economic benefits improving more than4000.00thousands yuan. The optimization results are accorded with the table of mine reserves and the practical production in Jinshandian Iron Mine.(6) Constructs the industrial grade optimization decision system of Jinshandian iron mine by Matlab software platform. This paper constructs the industrial grade optimization decision system based on the dynamic model and its optimal algorithm, by doing so, the industrial grade of Jinshandian iron mine can carry out dynamic management of daily operation. |
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