The mine water in Toyoha Mine is remarkably high in contents of Fe, Zn, SO₄ and some other ions compared with the other similar kind of mines that produce zincblend, galena and pyrite.
The author attempted to search the cause of this unusually high concentration of ions, by the experiments in which the powdered samples of each ores, were subjected to oxidation by air waterb ottle at varing temperatures.
The pyrite of Toyoha Mine has a high reactivity for oxydation, due to its imperfect crystal structure as confirmed by X-ray difraction pattern.
In the writer's view, the mine water was in the earlier stage a solution of FeSO₄ which was yielded from pyrite by its reaction with air and water. In the second stage, the solution became rich in Zn⁺⁺, as a result of reaction with the zincblend standing in the solution, Fe⁺⁺⁺ ion became also rich in the mine water as the oxydation proceeded.

抄録全体を表示

The percussion drilling tests of mine rocks by the drop hammer type drilling test machine were concluded in this second report.
This report includes:
1) parallel two blows test,
2) cross two blows test,
3) multiple blows test.
The parallel two blows test and the cross blows test were to measure dimensions, i. e. volume, plane area, depth, width, etc., of a compound notch made by adding the next pecussion blow of bit parallel-placed or cross-placed to the former single blow notch on a rock surface. In the multiple blows test, a measurement of the depth of the drilling hole made by multiple percussion blows of bit with a constant rotation angle of a bit was carried out.
Aims of those tests were to find the most suitable distance between parallel two blows to get larger notches, the most suitable cross angle of cross two blows and the most suitable rotation angle of bit for percussion drilling.
On those tests, the most suitable values for granite were showed as follows:
The most suitable distance was 0.65cm on 2m-kg blow energy. 0.90cm on 4m-kg blow energy, 1.15cm on 6m-kg blow energy.
The most suitable cross angle was 20° on 2m-kg blow energy, 24° on 3m-kg blow energy, 28° on 4m-kg blow energy, 28° on 6m-kg blow energy.
The most suitable rotation angle of bit was 24°-34° and there is a tendency to increase with a blow energy.

抄録全体を表示

We made a new portable dust meter using photo-transistor and discussed on the flotability of airborne dust.
Compared with the Funken konimeter and Rôken filter paper dust sampler, our photo-transistorized dust meter has smaller in size, lighter in weight and wider practical applications in the field of dust clouds measurement in our laboratory and some colliery.

抄録全体を表示

These are tests to examine quality of three types of mining power cable. i. e.
(1) the GR-1 insulated cable
(2) the polyethylen insulated cable
(3) the P.T.A. type paper insulated cable.
Test result
The first two (synthetic material insulated) are superior to the last from the stand-point of safety, mechanical and electrical strength, and economical use.

抄録全体を表示

We reviewed the Gibbs' adsorption equation and the relationship between contact angle and surface coverage presented by Rehbinder or Cook from the adsorption isotherm of dodecylammonium acetate on hematite reported by Gaudin and Morrow.
New equation γls=αX+_b was proposed, where γls and X denote the interfacial tension between solid and liquid and the surface coverage respectively and both α and b are constants. It was shown that this equation agreed well with the results obtained from the data in the range of the concentrations which is of interest from the flotation standpoint.
The bend in the adsorption isotherm of dodecylammonium acetate on hematite was speculated to be the saturated point of adsorbed ion lain flat on the interface and corresponded to the surface coverage of 25% from the dimension of the adsorbed ion. The same condition may also exist in the adsorption isotherm on quartz.
Discussions were also made on the surface coverage required to give the proper flotation performance.

抄録全体を表示

It is known that the function of auxiliary blades attaching to the impeller of Fahrenwald flotator is consisted in preventing settling of ore particles by applying agitation to the bottomof cell as subsidiary action assisting the main blade, while both the types of fluidization of are particles by auxiliary blades and the relationship of the main blade with auxiliary blades have not been made distinct.
From the point of view above, the authors inspected the flow patterns at the bottom of cell employing the apparatus composed of an agitator of batch-system and a model impeller. The results obtained are as follows:-
1) The critical agitating speed at which the are particles are fluidized is to be varied in response to the difference of geometrical condition in the relation between the cell and the impeller.
2) The critical setting-depth of impeller where the minimum critical speed is available under the same condition, is to be obtainable.
3) By lowering the critical depth with dish-like bottom to that of impeller installed and by applying bottom-agitation effectively with the main blade, the essential agitation is made possible by the minimum power.

抄録全体を表示

We studied to the effects of cobalt (II) and cobalt (III) in the electrolyte to the lead anodes and zinc deposit during the electrodeposition of zinc when used to the lead alloy anodes in various kinds.
The corrosion and potential of anode differ by the kinds of lead anodes, but there is lowered by the presence of cobalt in the electrolyte.
The current efficiency, cathodic potential and lead content in the deposited zinc showed various results by the kinds of lead anodes. In the presence of cobalt in the electrolyte, cobalt (II) is much lower the current efficiency, but cobalt (III) is prevented the loss of current efficiency.

抄録全体を表示

The corrosion of pure and silver-containing lead anodes in electrolytic zinc deposition has been studied under various compositions of electrolytes. The anode potential observed when the bath containing 60g/l zinc increases with increasing the acidity ranging from 50 to 200g/l. On the other hand, anode potential decreases with increasing silver content in the lead anode, irrespectiveof the compositions of electrolytes. The amount of anode slime increases with increasing acidity unless the silver content of lead anode exceeds 0.5%; above this the change is so small and almost negligible. The lead content of cathode zinc is proportional to the amount of anode slime.
From these results, some considerations can be made on the relation of anode potential, the amount of anode slime, distribution of lead in cathode zinc, and the lead content of zinc deposit.

抄録全体を表示