Mining Speed Research Articles

Numerical Simulating Research on Orifice Pre-splitting Blasting in Coal Seam

Aiming at the actual problems such as bad effect of gas drainage, slow mining speed, high cost and so forth of drilling along layers in mining face of coal seam of low air-permeability but high gas-content, effect of orifice pre-splitting blasting on crack extending in coal seam was studied through adopting ANSYS/LS-DYNA software. Different diameters and depths of holes were set in the simulation, and groups were divided through using method of controlling variable volume. Results show that when depth of hole is fixed, with diameter of hole increasing, time for elements at the same location to receive stress shortens gradually, and when diameter of hole is fixed, with depth of hole increasing, time for elements at the same location to receive stress prolongs gradually, that is, the bigger the diameter of hole is, the more easily cracks extend in coal seam, and the deeper the hole is, the more adversely cracks extend in coal seam. This conclusion can provide theoretical basis for researching the gas drainage effect of actually applying orifice pre-splitting blasting.

BARO algorithm and application in equipment fault diagnosis

It can solve the bottleneck of knowledge acquisition in mechanical equipment fault diagnosis through combining the data mining techniques and the fault diagnosis techniques. This paper presents the bitmap-base association rule optimisation (BARO) algorithm to aim at solving the problems of mining speed slower and the demand of internal memory bigger in association rules mining process. The BARO improves the data structure to reduce the scanning frequency of database and compresses the matrix to reduce the quantity of candidate itemsets in order to improve the speed of equipment fault diagnosis. Based on the BARO algorithm, this paper designs equipment fault diagnosis system.

Bitmap-Base Association Rule Optimization Algorithm and Application in Equipment Fault Diagnosis

The Apriori algorithm needs to continue scanning the database and may provide mass candidate itemsets in fault diagnosis process which causes the mining speed too slow and the computer memory too large. According to these weaknesses this paper presents the bitmap-base association rule optimization algorithm (BARO). The BARO improves the data structure to reduce the scanning frequency of database and compresses the matrix to reduce the quantity of candidate itemsets in order to improve the speed of equipment fault diagnosis. It proves that BARO is superior to Apriori algorithm in equipment fault diagnosis of efficiency and mining speed by a concrete example.

No-header-table FP-Growth algorithm

Concerning the problem of low traversal efficiency when searching the FP-tree for conditional pattern bases,a new no-header-table FP-Growth algorithm was proposed.The algorithm employed a recursively backtracking way to search for conditional pattern bases,avoiding traversing the same FP-tree path multiple times.Compared with FP-Growth algorithm in terms of theoretical analysis and actual mining performance,this algorithm greatly reduced the searching cost and improved the mining efficiency of frequent patterns by 2-5 times.Finally,the algorithm was used to mine association rules in telecommunication network alarms.The high mining speed,with the coverage of 83.3% against correct rules,shows that it is superior to FP-Growth both in time and space performance.

Evaluating natural resource projects with embedded options and limited reserves

This study proposes a Dynamic Option Simulation (DOS) approach to evaluate natural resource investment projects that contain several embedded options and limited reserves. To construct a practical pricing model, DOS combines simulation and dynamic programming techniques that can value natural resource investments with multi-variable, early exercise, various embedded options and finite reserve properties. A copper mine project offers a demonstration; the mine holder may temporarily close, reopen and abandon the mine at specific times before the expiration date. The mine holder may also accelerate mining speed to be optimal, referred to as the acceleration option. Numerical analyses of the copper price and interest rate effects on the copper mine value suggest that DOS can efficiently assess complex, multiple-variable, American-style real options problems.

Analysis and Optimizations on Retreating Mining Measures of Rock Burst Prevention on Steeply Dipping Thick Coal Seam in Deep Exploitation

Abstract With the reduction of mine reserves in shallow coal-bearing series, the mining proportion of steeply dipping thick coal seam in deep strata is increasingly high. Deep exploitation not only increases the chance rock burst happening in mine, but also there are some difficulties for the stability of corollary equipments in working face in the process of full-seam mining of steeply dipping thick coal seam. 4# coal seam of Huafeng colliery is under the geological condition of steeply dipping thick coal seam in deep mining. In the process of retreating mining, rock burst and stability of equipments always restrict the mine's production. Through comprehensive analysis of 4# coal seam, including the places of rock burst happened, comprehensive management actions of rock burst and the relevant mining method and so on, found that adopted the exterior entry layout of dislocated strata gateway in the colliery is still inadequate to improve the problem of stability of equipments along coal seam floor. Besides, continuous mining to the east is too long, reduce the mining speed and mining of protective seam are not effective measures, even the occurrence reasons of rock burst. In response to these issues, further proposed the internal entry layout of dislocated strata gateway, through theoretical and experimental analysis, getting that the reform of tunnels arrangement not only improve the stability of mining equipment, but also change the present situation of rock burst of 4# coal seam fundamentally in Huafeng colliery.

Multi-Scaling Sampling: An Adaptive Sampling Method for Discovering Approximate Association Rules

One of the obstacles of the efficient association rule mining is the explosive expansion of data sets since it is costly or impossible to scan large databases, esp., for multiple times. A popular solution to improve the speed and scalability of the association rule mining is to do the algorithm on a random sample instead of the entire database. But how to effectively define and efficiently estimate the degree of error with respect to the outcome of the algorithm, and how to determine the sample size needed are entangling researches until now. In this paper, an effective and efficient algorithm is given based on the PAC (Probably Approximate Correct) learning theory to measure and estimate sample error. Then, a new adaptive, on-line, fast sampling strategy -- multi-scaling sampling -- is presented inspired by MRA (Multi-Resolution Analysis) and Shannon sampling theorem, for quickly obtaining acceptably approximate association rules at appropriate sample size. Both theoretical analysis and empirical study have showed that the sampling strategy can achieve a very good speed-accuracy trade-off.

Mining pattern of the honeysuckle leaf‐miner Phytomyza lonicerae

SummaryThe mining pattern of the honeysuckle leaf‐miner Phytomyza lonicerae which feeds on Lonicera gracilipes was analyzed with special reference to the avoidance of parasitoids' attacks. The leaf‐miner makes the linear mine with branches and crosses by turning and branching, off the backtracking mine. Both average numbers of turnings and branchings were about 4. The speed of mining was 1.5 times faster in backtracking than in advancing. The mine width increased as the mining larva grew and total volume of consumed plant tissue was nearly constant independent of variability of the number of turnings and other characteristics of the mine. The majority of larval mortality were due to attacks by parasitoid wasps (Chrysochairs pentheus and Diglyphus minoeus), which locate the present position of leaf‐miners, by tracing mine tracks, and wasps attack leaf‐miners at a higher rate in backtracking than in advancing. The adaptive significance of branching and crossing by leaf‐miners was discussed in terms of the reduction of parasitoids' attacks.