Recent developments in the dressing of non-sulphide minerals of copper, lead, zinc, tungsten, tin, and fluorine were reviewed on the basis of the literature published for the past ten years.
Because of abundant pieces of research work on the flotation of those minerals, this discussion focuses mainly on flotation and related problems, namely, the flotation fundamentals, the development of flotation reagents, the modification of flotation technique in the fine particle treatment, the combined processes of flotation with the other dressing or chemical processing techniques, and so forth.
In contrast to the successful practice of sulphide mineral fltation, it is very important for the non-sulphide mineral flotation researchers and engineers to establish the principle of non-sulphide mineral flotation and to obtain a successful application of flotation to the non-sulphide separation practice.

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It is well known that the external effects of a detonating explosives are of two elements in a rock blasting due in the first place to the shock wave and in the second place to the expansion of the detonation products. In the case of confined charged blasting, which of these two elements could be the main part of the effective energy required for complete loosing of the rock?
It is not solved yet experimentally, because of many difficulties and restricts in experiment with explosive, depending on its rapidity of reaction, enormous pressure and high temperature.
So until now, the large number of researchers had made an experiment in such a way that they gave the whole energy of these two elements to the rock at a time, trying to put an end to the arguments.
But here we took the new method for our experiments that could give the two different elements to the rock separately: releasing the detonation products from the confined bore hole artificially, at the suitable moment when the gas expansion is just going to work, after the moment when the dynamic energy have been given thoroughly to the rock as same amount as usual.
The result of this experiment showed that the action of the gas expansion could be the main part of rock breakage. And we could confirm that in properly balanced explosive shot, the rock was not broken only by the shock wave.
For example, with the conditions of which the burden W equals to 35 cm, the amount of the charged explosive (18% NIG) is 34g, the diameter and the length of the borehole are 30mm and 36cm respectively, the rock was broken completly, and the blasting result was excellent.
And under the same conditions except for W=30cm, and without the work of gas expansion, the rock was not broken, and remained without any effect from the standpoint of practical blasting result.

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According to the remarkable advances in electromagnetic detecting technique for steel wire rope, it becomes possible to estimate with higher accuracy the static strength of wire rope being used. In addition to this, it is very important to know the dynamic tension loaded on the wire rope during winding.
From these considerations, the authors tried to prepare a tension meter of right-angled triangle type. The reliability and accuracy of this equipment was examined in the laboratory. And afterwards, it was also tested to measure the dynamic tension of the wire rope being used in the inclined and vertical shafts in a coal mine.
From these results, it was confirmed that this equipment is suitable for the practical use: the dynamic tension of vibrating wire rope can be measured accurately.

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This paper gives the results of dust survey taken place in 79 rock crushing plants in Tokai District. The airborne dust concentrations were surveyed with a high volume air sampler, the size distribution of airborne dust were calculated with an optical microscope attached a Patterson-Cawood graticule and the free silica contents of dust were analysed by the modified phosphoric acid method. The main results of the survey are as follows:-
1. On the airborne dust concentration......Among various equipments, the third or more higher order crushing unit produces the highest concentration. The dust concentration in the leeward from the origin decreases in accordance with the following formula,
C=C₀e^-0.072T/0.01369x²+0.314x+1
where, C=airborne dust concentration at distance x m and time T sec C₀=airborne dust concentration at the origin
2. On the size distribution of dust particles.........The mode of size distribution of deposit dust differs according to the kind of equipments. On the contrary the airborne dust from every kind of equipment has the nearly same size distribution. The average respirable dust concentration below 5 micron surveyed near the origin is about 2.5% in weight.
3. On the free silica content.........The maximum content is 76.22%(silicated sandstone) and the minimum 0.22%(peridotite). Most parts of sample contain between 30-50% free silica.

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An experimental study concerning the relationships between specific fracture energy and specific surface area of fractured product in single particle crushing under slow rate of loading (0.3-1t/min) in a coarse size range is carried out by using various shaped specimens, i. e., spheres, disks, cylinders and cubes made of silicaglass, borosilicaglass, quartz, feldspar, lime stone, marble, gypsum and talc.
The fracture energy is calculated by the load-deformation curve and the specific surface area S_w [cm²/g] is calculated by the following equation
S_w=f/100ρΣM_i/X_i...(1)
where f assumed to be 6 is the shape factor, ρ is the density and W_i is the weight percent of fractured product corresponding to the size X_i.
From the above experiment the following result is obtained that the specific fracture energy. E/M [kg-cm/g] is proPortional to the specific surface area of fractured product S_w [cm²/g] irrespective of kinds of samples, shape and size of specimen.

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The valuable minerals of our plant (started since October, 1968) are scheelite, chalcopyrite and magnetite. The ore is ground to all minus 48 mesh by one-stage ball mill-classifier circuit. Copper concentrate is, first, floated by xanthate, iron concentrate is' next, separated- by magnetic separator and finally scheelite is floated by all-flotation method after intermediate thickening.
The 20% WO₃ concentrate from rougher flotator using caustic soda, water glass and fatty acid contains scheelite, apatite, calcite, sulfides (chalcopyrite and pyrite) and silicate gangue minerals. From this concentrate, first, sulfides are fejected by sulfide-reverse-flotation in batch flotator. At this stage by hydrochloric acid pH 0.1-1, calcite and apatite are changed to water-soluble state (Ca⁺⁺, Cl^-, PO₄4^---, etc.) and fatty acid adsorbs to sulfide mineral surfaces preferentially, so only sulfides float. Sinks (scheelite and silicate gangue minerals) after centrifugal dewatering and washing are repulped in the batch flotator and aerated at pH 2-7. This flotation pH must be selected by the quantity of residual adsorbed fatty acid. Generally speaking the more fatty acid adsorbs, the lower the flotation pH must be set.
At this stage fatty acid adsorbs to scheelite mineral surface preferentially, so only scheelite floats and 60-70% WO₃ high grade concentrate is able to be separated from silicate gangues by pH and batch flotation time control.
In this plant these flotation processes are called “Dephosphorization and Grade Up Process”.

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For the purpose of investigating some behavior of thiourea in the copper electrolysis, quantitative microanalysis of thiourea in the electrolyte was confirmed by improving the method offered by previous workers which was based on the fact that two molecules of thiourea react exactly with one molecular iodine according to the following chemical reaction.
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A known amount of iodine was added excessively to the electrolyte containing thiourea and the excess quantity of iodine was measured photometrically after extraction with toluene or after reaction with starch. The photometric measurements were determined to be made at 500mμ and 520mμ of wave lengths in the cases of toluene and starch, respectively.
The influences of temperature, pH, and the concentrations of iodine solution at each step of the analytical procedure were examined.
The method of preventing thiourea from oxidation and the treatment of removing such reducing substances as As³⁺, Fe²⁺ and Sn²⁺ from electrolyte were also discussed.

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