This report treats an analysis of the ore grade of limestone by means of thermogravimetry. Although a simple wet chemical analysis (titration lime method) is well known for an analysis of the ore grade limestone, it is not easily employed at mine site because it requires an acid reagent and skill. Thermogravimetry with stepwise heating can be operated easily and safely. Limestone sample releases H₂O and CO₂ on heating. The ore grade of the sample is calculated by the sample weight ratio before and after the release of CO₂. A stepwise heating maintains a sample at each reaction temperature constant while following three reactions have occurred:(1) 200°C; release of physically absorbed water (2) 650°C; release of structural water of clay minerals contained in the sample (3) 1, 100°C ; release of CO₂.
When the weight of the sample is the same as that of two minutes before, the sample is heated up to the next step.
By this method, a sample which is sized under 5mm and weight 15 grams, for example, is analyzed in one hour without predrying. The correlative cofficient between the data obtained by the wet chemical method and those by this method is 0.995. This method has-been carried out in the Higasitani mine of Mitsubisi Mining & Cement Co, Ltd since 1986. Sample heating, weight measuring and ore grade calculation are performed by pocket-computer system. Theequipment does not require a special room for analysis and more than ten times larger amount of sample may be analyzed in a shorter time, comparing with the chemical method which is conventionally employed in Japanese mines.
By use of this analyzing system, the dispersions of the ore grades have been reduced when raw materials of cement are mixed in cement producing process.

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In the previous report it was clarified that montmorillonite is one of the factors which dominate the susceptivity of mechanical properties of coal measure rocks to the influence of water.
In the present paper discussion is made on the basis of experimental data on two other mechanisms to which the lowered rock strength with increased moisture is ascribed. Firstly, it is shown that adsorption of water reduces the free surface energy, which leads to the decrease in strength of the rocks in thelower humidity range. Secondly, it is made clearthat reduction of capillary tensions with increased moisture can lower the strength of the rocks in the wider range of humidity.

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A practical application for evaluation of rock deformability by means of the crack theory is discussed and presented. In the theoretical analysis presented in the 1st report, discontinuities of rock mass are assumed to be represented by circular cracks and to be classified into two types, i. e., theopen cracks and the closed cracks. The effective Young's modulus E of rock mass is expressed as eq.(4) and it is a function of four parameters which are the intrinsic Young's modulus E, the frictional coefficientμon the discontinuity surface, the crack densityΦand the state coefficient q of discontinuities. In this paper, the practical procedures to evaluate the four parameters are discussed and it is pointed out that E andμshould be determined from the laboratory test and the joint roughness investigation, and a combination of the scanline survey and the seismic exploration are available to evaluateΦand q .
For an application of the theory and the procedures to in-situ rock mass, the field investications have been carried out at two sites of Yanahara mine. The four parameters have been quantified and in-situ Young's moduli are determined theoretically. From the reasonable, agreements of the results with those of the back-analyses, it is concluded that the theory and the procedures proposed have a promise to estimate rock deformability quantitatively.

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In coal mines AE method is applied to testboring in an attempt to obtain the necessary information about the stress distribution in coal seams where coal outburst might occur. AE counts are measured as the main value in AE activities. This value seems to be affected by borehole diameters. There havebeen in a state of uncertainty with regard to the relation between AE counts and borehole diameters.In order to make clear this uncertainty, six boreholes of various diameters were drilled, and duringthe drilling AE counts were measured.
As a result of this tests, AE ring down counts, (Y) during boring are related to borehole diameters (X) by the following equation: Y=2.3×10^-2X2^2.004Theoretical formula for the relation between X and Y derived by using the probability theory agree with theexperimental result.

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The acoustic emission activity from coal gas outburst was monitored during an entry drivage by blasting against the 11th coal seam in SUNAGAWA Coal Mine. In this observation, the source location analysis was conducted to determine the location of the acoustic emission activity which occurred prior to the coal and gas outburst using a multi-channel acoustic emission monitoring system. Moreover, themethane gas concentration in the driving face were measured successively after blasting.
As the observational results, both acoustic emissions and gas emission after blasting increased and decreased remarkably in the approaching process of an entry driving face to outburst-prone fault zone, as well as the cases of cross-measure drivages presented in the first report of this study. Additionally, the continuous AE waveforms similar to the waveforms of gas outbursts were detected immediately after each blasting prior to the coal and gas outbursts. On the other hand, from the source location analysis and the frequency distribution of acoustic emission events against median frequency, it was revealed that the acoustic emission activity occurred locally ahead of the driving face. Therefore, these flactuations in acoustic emission activity and gas emission after blasting in the approaching process of driving face to outburst-prone area seem to be related to a local fracturing activity in the gas outburst source ahead of the driving face.

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A method to estimate the remaining strength of locally corroded P. W. S. ropes was developed. In this method, the degree of corrosion first evaluated in terms of the loss of cross-sectional area by magnetic inspection. Second, the remaining strength is estimated from the area loss by a numerical simulation of the load-elongation behaviour of the corroded P.W.S. With this method the remaining strength was considerably lower than expected from the area loss, because the P. W. S. consists of wires corroded to various degrees. To verify the validity of this method, bundles of partially thinned wireswere examined as a model of locally corroded P.W.S. The area loss and the strength for these specimens were in good agreement with the actual values. The method was then used to evaluate the degree ofdeterioration of P.W.S. 75 ropes that had been seriously corroded during 15 years' exposure to weather as suspension members of roofing. Two P.W.S. 75's were removed from the roofing for replacementand then subjected to tensile test. The remaining strength of those ropes was successfully predictedbythis method.

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Pick failure is often induced by severe vibration of cutting drum when the roadheader is trying to cut the rock of high strength. This would have two consequences. First, the direct cost of picks is increased.Second, the time lost in changing picks may become a significant portion of the overall downtime. For this reason, the analysis ofvibration of roadheader is an important problem to apply the roadheader to the rock of high strength. However, neither the force induced by cutting nor the model of roadheader to analyze the vibration are known mainly because of the complexity.
In this study, first, the force induced by the cutting is examined with the aidof newly developed computer program. The calculated results are shown in Table 1, which indicate that on cutting of highstrength rock, the dominant frequencies of induced force are 12.5, 0.83 and 11-23 H_zdepending on the causes.
The simplified vibrational model of roadheader to analyze the mode and natural frequency is proposed. The calculated results with the computer program developed for this study indicate that the resonance may occur with the primary or secondary mode of the estimated natural frequency of 5-8, 10-15 Hz respectively. Also, the torsional vibration of shaft-gear system from the cutting drum to the electric motor are examined by the transfer matrix method and foundthat the vibration of the shaft-gear system may not be severe problem.

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The purpose of this paper is to investigate the form of Probability Density Function (PDF) of pressure fluctuation in solid-liquid flow using the Maximum Entropy Principle (MEP).
By the analysis using MEP, it is found that PDF is expressed as Eq.(6), In Eq.(6).λ_k (k=0, 1, N) are the unknown coefficients and they are determined by the results of the experiment.
The experiments of pressure fluctuation measurement are carried out in the apparatus shown in Fig. 2. The pressure is measured by the pressure transducer, and sampling clock is 10 msec, sampling number is 2048, cut off frequency in Low Pass Filter is 10 Hz.
As shown in Fig. 3 and 4, PDF is expressed by the MEP distribution of 2 moments in the higher velocities. On the other hand, as shown in Fig. 9, PDF is not expressed by the MEP distribution of 2 moments and is expressed by the one of 4 momests.
In the result, it is concluded that PDF of pressure fluctuation in solid-liquid flow is expressed by the MEP distribution of 4 moments.

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The behaviour of sulfur and oxygen in copper electrorefining has been investigated. The form of anode slime and the dissolution state of anode surface after electrolysis as well as the effect of dissolved oxygen in electrolyte have been revealed. It was clarified that the anode passivation occurs depending on the concentration of oxygen and sulfur in the anode.
In the case of anode copper with low oxygen content, the fine Cu_1.96S particles in the matrix remained on the surface, thus forming the compact layer of anode slime and caused the anode to passivate very sensitively. In the case of high oxygen containing anode, Cu_1.96S particles were coasened and fell off the anode surface, and the anode passivation was not observed. The anode passivation was greatly accerelated with increasing current density, and it was unaffected by the concentration of dissolved oxygen in the electrolyte.
The anode containing sulfur, arsenic and oxygen was also investigated in termes of the form of anode slime and the anode passivation. On the electrolysis of the anode with high arsenic content, the fluffy slime of Cu₃ As was filled up in among the Cu_1.96S particles and was occured the anode passivation with great facility. Copper anode of low arsenic content did not passivated since the slime layer tended to fall.

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Phase separation behavior between a molten sulfide and molten oxide is investigated in a FeS-FeO-AO ternary system where AO is a strong acidic oxide such as B₂O₃or P₂O₅. Experimental results indicate that a wide miscibility gap occurs along the increment of a strong acidic oxide component, The immiscibility behavior based on the experimental results is compared with a previous work on the FeS-FeO-SiO₂system to describe the effect of a strongacidicoxide component on the phase separation between molten matte (sulfide) and slag (oxide). Basedupon the regular solution model, ternary immiscibilities for various smelting systems are explained thermodynamically from the binary data.

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