Copper was discovered at the present Sipalay Mine in midthirties, and was explored by San Remigio Mining Co. for years before the World War II, but did not produce much except some high grade oxide ore.
After the war, several mining companies made inspection of the property but no attempt was made to develope it until 1953. Mitsui Mining & Smelting Co., at the invitation of Elizalde & Co., made an inspection and found it to be huge “Porphyry Copper” type deposit. To undertake more through exploration, an exploration company, Sipalay Copper Mining Co., was organized under Elizalde & Co. and started exploration in full blast. After two years of extensive and intensive trenching, diamond drilling and tunnelling, 12 million tons of are assaying 0.9% copper were blocked out in Binuling orebody.
In the fall of 1955, it was decided to develop and exploit it under the management of the Present Marinduque Mining & Industrial Corp., Considering the shallow occurrence of the orebody and large lateral extent, open pit mining was adopted. Accordingly, by January 1956 the construction of 4, 000 tons/day mill and stripping of Binulig orebody were started and by May of the following year production commenced, followed by first shipment of concentrate in August.
While concentrating the mining operation in Binulig, exploration of other areas of the property was continued which resulted in blocking out of 8 million tons in Baclao area by 1959 and delivery of are therefrom started in 1960. On the other hand, the results of diamond drilling in Binulig and the geological observations made as it was being mined, all pointed toward the possiblity of existence of another orebody in the adjoining area across the river. This area was a rice field owned by a private party, so the diamond drilling was started soon after its purchase in 1961. Beyond expectation, this developed into huge orebody now known as Cansibit deposit.
With the discovery of Cansibit, mill was expanded to 5, 000 tons per day in 1963 and at the same time its development was undertaken. By January 1965 three pits, namely, Binulig, Baclao, and Cansibit were producing and in November of the same year, copper production per month exceeded 2 million-pound mark for the first time, of which record was broken repeatedly during the subsequent months in 1966.
The are reserve as of January 1, 1966 reached 75 million tons which justified the further expansion of the mill and preparation is well under way to mill 6, 500 tons/day by January 1967. By then, Binulig pit will be mined out after producing 11 million tons of are and will give way to Cansibit which will be the major producer for years to come. It is noteworthy that Sipalay is the only producer of molybdenite concentrate in the Philippines since 1959. The copper production up to the end of 1965 amounted to 72, 000 million tons all of which were exported to Japan.
The present paper is to introduce this remarkable mine to Japanese mining circle, principally on the mining aspect of the operation which will include pit design, equipment used and their performance, problems encountered, specially on the drainage problem of Cansibit pit. Special mention is made on the use of Sauerman excavator for the stripping of Cansibit orebody.

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The aim of this study is to prevent the risk of coal dust explosion and to reduce the health hazard of miners by consolidating coal dust deposited on floor, ribs and roof-skim.
Deposition of coal rich dust on a mine roadway might increase the risk of coal dust explosion, if a substantial amount of coal dust remains loosely on the surface of the road.
This paper describes the effect of the consolidation of deposited coal dust by spraying deliquescent salts, such as CaCl₂, NaCl, MgCl₂ and antirust agents or surface-active agents.
Experimental results abtained are as follows;
1) Increase of moisture or suppression of its vaporization in deposited coal layers is due to hygroscopei c phenomenon of salts.
2) Suppressions of coal dust are gained excellently by consolidating action of salts.
3) Inflammability of coal dusts is loweredby addition of salts.

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The wave of rope for colliery and mining purposes shows many faults in using. The causes to waving come from both manufacturing and using rope.
The wave of rope is formed by plastic bending and twisting. As the curvature and twisting degree, of plastic strain of rope vary with the kinds of ropes, we must take them from the bending and twisting properties, which have been tested preveously for each rope. From these values we can calculate the diameter and pitch of wave in rope.
In this study we explain theoretically the influences of the wave property of wire and the manufacturing condition upon the wave property of rope and the condition to manufacture the waveless rope.
To prevent the wave of rope in using, it is necessary not to form plastic bending and twisting-generally to unwind rope rightly, not to bend or twist rope and not to scrub rope severely.

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In order to study the mechanism of activation of pyrrhotite by heavy-metallic ions in flotation, theadsorbabilities of Cu²⁺, Hg²⁺, Ag⁺, Cd²⁺, Pb²⁺, Zn²⁺, Ni²⁺ and Co²⁺ ions on the pyrrhotite were studied. Then the amounts of ethyl xanthate adsorbed on the pyrrhotite which had been activated by these respective ions were determined at various pH values of the pulp. Also the floatabilities of the pyrrhotite conditioned with the solution containing these ions were measured.
From these experimental results, it was shown that Cu²⁺, Hg²⁺ and Ag⁺ ions were strongly adsorbed on the pyrrhotite accompanied by the replacement of Fe²⁺ ion on the surface of pyrrhotite; that the amounts of ethyl xanthate adsorbed on the pyrrhotite fairly increased only when the pyrrhotite had been pretreated by Cu²⁺, Hg²⁺ and Ag⁺ ions; and that the floatability was promoted by the presence of these respective ions.

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In this study, the extent of variation of the floatability of pyrrhotites in xanthate flotation wasmeasured.
Relation between the floatability and crystallographic, magnetic and oxidation properties were also investigated.
The main results obtained are as follows:
1) The variation of about 30 percent in flotation recovery was recognized under the experimental condition used in this study. It may depend upon the fact that there is a difference in floatability between monoclinic pyrrhotite and hexagonal one.
2) The floatability increases with an increase of the intensity ratio of two reflections (called aand b-reflection respectively in this report) appearing in the 2θ range from 55° to 57° using iron radiation. The floatability also increases, with an increase of the magnetic susceptibility and the oxidation rate, with a decrease of the interplanar spacing. Namely, the floatability depends upon the abundance of monoclinic crystal in pyrrhotite.
3) On a basis of the stage in course of oxidation of pyrrhotites, the following three may be expected. a) The relationship is similar to the article (2). b) The relationship is opposite to the article (2). c) It is difficult to find a difference in floatability based on a difference in properties of pyrrhotite samples.
4) Besides, “Effect of Activation with Copper Sulphate” and “Relation between Floatability with Xanthate and Natural Floatability” were also discussed.

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Studies were made on the reduction roastings of dead-roasted complex sulfide are and the dilute sulfuric acid (0.4N) leaching of the reduction-roasted calcine for a purpose of separation of metallic copper from zinc oxide, both of which were contained in the calcine.
In case that the extent of the reduction was so insufficient that iron oxide was not entirely reduced to FeO and Fe₃O₄ remained in the calcine, the separation was not attained on account of dissolution of the metallic copper. The copper dissolution is caused by an oxidizing effect of Fe³⁺-ion which forms when the magnetite dissolves into the leaching solution in the presence of metallic copper.
Copper dissolution and zinc extraction were 20% and 95% respectively, when calcine, which was roasted by means of a batch-type rotary kiln of a laboratory scale for 2 hours at 850°C in an atmosphere composed of 10% CO, 10% CO₂ and 80% N₂, was treated with 0.4N H₂SO₄.
Coke was inadequate as a reducing agent for this purpose, because it could not reduce Fe₃O₄ to FeO at 850°C
It was also ascertained that a considerable amount of zinc oxide vaporized in a weakly reducing atmosphere even at 750°C. This unexpected fact was resulted from formation of zinc vapour as a reduction product of ZnO by CO.

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Vapor pressures of bismuth and antimony have been measured for liquid bismuth, antimony, copper-bismuth and copper-antimony alloys respectively, in the temperature range from 900°C to 1, 200°C by the use of transportation method. The vapor pressure of each gaseous species, such as Bi, Bi₂, Sb, Sb₂, and Sb₄, and total pressures were calculated from the available data on the equilibrium among these gas species of metals and the data obtained in the current work. The results shown below are agreed well with the values reported by the others:
logP (Bi+Bi₂)(atm)=-8970/T+4.71 (900°-1200°)
logP (Sb+Sb₂+Sb₄)(atm)=-6030/T+2.99 (900°-1200°)
Activities of bismuth and antimony were calculated from the vapor pressures using the following relation
a_i=(P_in/P°_in) ¹/n
where n is the number of atoms per molecule in vapor phase. On the other hand, the activity of copper were determined by the Gibbs-Duhem integration. For Cu-Bi system, the activity-composition curves show positive deviations from the Raoult's law. On the contrary, the activity of antimony shows a negative deviation especially in the copper rich side of Cu-Sb system. The maximum values of the heat of mixing were 1.5kcal/mole at N_Bi=0.52 for Cu-Bi system and-2.8kcal/mole at N_sb=0.26, near the composition corresponding to the intermetallic compounds, for Cu-Sb system.
In addition, the removal of bismuth and antimony from crude copper have been estimated from the activity coefficients of these elements in the infinite dilute solution, and the results indicate that the contents of bismuth and antimony in crude copper can not easily be reduced even by oxidation or vaporization.

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