The paper presents the results of two-dimentional orthogonal cutting experiments on such a brittle specimen as plaster to estimate and analyze the cutting forces on rake surface and clearance surface of the blade-type tools.
The cutting experiments were carried out in two method at the same depth of cut and with the same tool; in the first method the specimen was formed into a right-angled buttock, but in the second it was prepared to notched shape on front wall of the buttock. The second experiment was aimed to eliminate the effect of resistance on the clearance surface of the blade on the cutting forces.
The experimental results were: the chips formed in both tests were the same in shape and size, but the cutting forces measured in both were not equal.
From these results it was considerd that in the first method, the cutting forces were measured as the resultant forces on two faces of the tool, but in the second they were measured as only the forces on rake surface. Thereby we could estimate the resistant forces on the clearance surface from the differences of the forces measured in both tests.
Furthermore in these experimental ways rake angle and depth of cut were varied. From these measurements it may be concluded that:
1) the cutting forces in normal orthogonal cutting are the resultant forces of those on both surface of the blade
2) the resistant forces on the clearance surface are hard to neglect, and they increase with the depth of cut.
It is important that if we intend to make clear the mechanism of the chip formation in cutting, we must consider the cutting forces on the rake surface and not adapt the valves of resultant forces.
Further study along these lines will be continued in our laboratory.

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The rate of flow in mine airways is influenced by the natural ventilation pressure in each mesh, which depends upon the distribution of altitude, temperature and humidity along the mesh. The temperature and humidity, however, are affected by the rate of flow. This relationship should be considered on analyzing ventilation networks. The authors have investigated how to practice such an analysis and have obtained a computer program for this purpose.
This program consists of a subsystem for networks analysis and a subsystem for temperature and humidity analysis. The latter is a kind of trial and error methods, in which the heat transferred from rock, machines and soon to air current, the variation in altitude and the evaporation of water on rock surface are taken into account. By comparing the results of calculation with those of measurement, it has been ascertained that this program yields considerably good results and can be put to practical use.

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An experimental study of the size effects and the energy laws of single particle crushing under slow rate of loading in a coarse size range was carried out by using irregular shaped specimen made of borosilica glass and 4 kinds of minerals.
The mass of particle ranged from about 0.01 to 2 gram for borosilica glass and from about 0.1 to 70 gram for 4 kinds of minerals and rate of loading was 0.3t/min.
A summary of experimental results was as follows I) as illustrated by equation (9) the strength of irregular shaped particle is proportional to its breaking load and inversely proportional to the square of the distance of loading points, II) the Weibull's coefficient of uniformity obtained for irregular shaped particle was approximately equal to that obtained for spherical particle, III) the energy law of equation (4) concerning the single sphere crushing can approximately be applied to the estimation of the energy requaired for fracture of irregular shaped particle.

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Pyrite samples from one of the typical Kuroko deposits, Hanaoka mine in the northern part of Japan, were studied from crystallographical and surface topographical viewpoints in the previous report.
The present paper deals with the relation between structural deviation of pyrite and its surface chemical as well as flotation characteristics.
The values of ζ-potential and pH as ζ=0, phζ=0 could be correlated with non-stoichiometry, crystallographic indices of pyrite and the distribution of etching structures on the mineral surface; the less the value of S/Fe and the lattice constant, the higher the pH value of pHζ=0
The results observed could be explained from the semiconductive nature of non-stoichiometric pyrite.
Batch flotation tests on the sized pyrite particles (53/37μ) using xanthate as collector at pH 1-12 showed that the flotation rate constant was dependent on the value of S/Fe, crystallographic factors and the distribution of etching structures.
Notably in this connection the inversed relationship was obtained under acidic and alkaline conditions, suggesting different adsorption mechanisms of xanthate ions on pyrite for different pH conditions.

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With the view to study the properties of the organic dithiophosphates and their related compounds as mining chemicals, dithiophosphates (Aerofloats), monothiophosphates and phosphates were chosen.
The solubilities of metal salts in various solvents, the oxidation reaction of those reagents, the complexformation reactions, the molecular-association in benzene solution and the contact angle on minerals in aqueous solutions were examined and the differences between those three reagents could be interpreted by the soft-hard Lewis acid-base theory.
From the results of the contact angle measurement it was found that the monothiophosphate ion might have a good selective property as presented by the American Cyanamid Co.

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Activity of each component in liquid copper-lead-bismuth and copper-lead-tin ternary systems has been determined by the use of transportation method at 1, 100°C.
Vapor pressures of lead and bismuth were simultaneously determined by the chemical analysis of the condensate transpired from the copper-lead-bismuth system. The activities of bismuth measured were in good agreement with those calculated from the Gibbs-Duhem equation by using the activities of lead measured.
On the other hand, the activities of lead for the copper-lead-tin system showed a plateau in the range of concentration 0.2 to 0.6 in NPb along the line of N_cu/N_sn=7. The activities of copper and tin in the copper-tin binary system estimated from the data of ternary system fairly well agreed with the results reported in the previous paper.
The interaction parameters which are representing the effect of lead, bismuth, and tin on the activity of lead in adilute copper base solution were estimated to be:ε(Pb)/Pb=-3.6, ε(Bi)/Pb=-2.6, ε(sn)/Pb =+3.3 (1, 100°C).

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The anode consisted of intimate mixtures of titanium dioxide (or titaniferous slag), pitch coke and pitch (or tar) was obtained by moulding method and baked at 800°C-900°C in the electric furnace. The anode was applied in a 150-200A magnesium reduction cell containing fused magnesium chloride and sodium chloride mixture.
The following results were obtained.
1) In the 150 A electrolysis by the anode containing titanium dioxide, the main constituents of the gas collected in the anode compartment were titanium tetra-chloride, carbon monoxide and carbon dioxide and its free chlorine content was less than 3 per cent. The cathodic current efficiency was very low owing to some unsuitable cell constructions for magnesium collection.
2) In the 200A electrolysis by the anode containing titaniferous slag, the reaction between the anode constituents and free chlorine was better than in the case of the anode containing titanium dioxide, while the cathodic current efficiency was yet low (about 60 per cent), because of mixing of impurities from the anode into the electrolytic bath.
It will be possible to obtain better results by improving the cell construction and operation.

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