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ART. II-Report by Lieut. JOHN GLASFURD, Executive Engineer Kumaon division, on the progress made up to the 1st May, 1839, in opening the experimental Copper Mine in Kumaon.
The ground selected for the experiment is at Pokri in the Pergunnah of Nagpoor in Gurhwal, where mines of Copper have long been worked.
The mines, or rather excavations, are numerous, and are situated on the western side of a steep hill in talcose schist and clay slate. The soil is extremely soft and decayed, and has defied all the efforts of the present race of native miners, according to whose accounts the workings do not extend beyond 120 feet from the entrance in any of the excavations, which are constantly liable to accidents, and of which a new one is generally commenced after every rainy season. It is however universally admitted that the Pokri mines have been very productive, and it is said that the one known by the name of the Rajah Kān, yielded one year upwards of 50,000 rupees. Judging from the ruins of the houses, workshops, &c., and the accumulation of slag, the working must have been carried on, on an extensive scale.
The village of Pokri is situated about 6,100 feet above the level of the sea, and 3,800 above the Alukmenda river, from which it is distant nearly nine miles; the distance from Almora is eighty-six, and from Sreenuggur little more than thirty miles, and to both of these places there are good roads. The climate is good but changeable, owing to the vicinity of the Snowy range; and the temperature is from the same cause as cold as that generally found at elevations from 7,000 to 7,500 feet. The vegetation, as might be expected, is European in its character, and the forests of oak, rhododendron, and the common long-leaved pine are almost inexhaustible in the immediate neighbourhood of the mines. During the greater part of the year there is water sufficient for washing the ores in the immediate vicinity, and at a distance of about two miles, there is enough for the purposes of machinery throughout the year. The village consists of eighteen to twenty-two houses, and from sixty to eighty inhabitants, who are chiefly of the Chowdry and Mining castes. The right of mining was rented by them from Government on a quinquennial lease of 100 rupees per annum, which expired about a year ago; but the people are so poor, and their resources so limited, that they have been unable to undertake any new lease, and indeed before the present experiment was commenced they hardly attempted more than the re-smelting portions of the slag from the old working.
The mining ground lies in two ravines, both on the western face of the hill, and about 500 yards apart, separated by a low ridge, the direction of the ravines being nearly east and west. The most northern of the two, and in which the village is situated, is where the old mine called the Rajah Kan was. The right, or northern side of the ravine is of dolomite, the left being talcose schist, which forms the ridge separating the two. The southern ravine is known by the name of Chumittee, and is full of old excavations; the formation is talc, bounded on the south by a dolomite limestone, and on the north by the low ridge of talcose schist through which in one or two places granite protrudes. Besides these, there are several other localities on the same hill where copper has been extracted; one very promising situation is an old mine known by the name of the Dandu Kan, or hill mine, about four miles from Pokri, and there are also many other places in the Pergunnah of Nagpoor, where copper is known to exist.
The experimental works now in progress were commenced in January last, and consist of two adits, or galleries, one in each ravine; that in the northern, or Rajah Kān ravine, has been driven and secured with timber to a distance of 149 feet from the entrance; the gallery is six feet high by three feet wide, and the frames, which are oak branches of three and a half to four inches diameter, are placed from two to two and a half feet asunder; the top and side sheeting are also of oak branches, the diameter of which is about two and a half inches. The gallery is being carried in with a slope of one inch per foot nearly on the ruins of an old working, which has been roughly secured with timber, but has long fallen in. The soil is an alluvial deposit filled with masses of rock, chiefly of dolomite, and the water proceeding from the gallery is slightly impregnated with sulphate of copper. When about sixty-three feet from the entrance the superincumbent soil gave way, and fell in on the head of the gallery; this breach has been cleared and converted into a rough shaft, which at present answers for the purpose of ventilation, but as it is directly in the line down which the water runs in the rainy season, it will probably be necessary to close it.
In the Chumittee ravine a gallery has been driven and secured with timber to a distance of 111 feet from the entrance; it is in size and mode of timbering exactly similar to the other, the slope averaging only half an inch per foot. The first seventy-five feet were driven through talc slate, with occasional beds of quartz, in which were small quantities of copper pyrites; the next six feet passed through an old working which apparently went down obliquely, and had been regularly timbered with deal; on reaching this working, traces of copper were found, but were lost on entering it. The next twenty-four feet went