« AnteriorContinuar »
Dhárwár series; in which respect it seems to resemble the Wainad region, which is peculiar and unique in having its auriferous reefs developed in the crystalline or gneissic series. The further examination of this tract will be taken up later on in the year. Considerable additions were made to our knowledge of the occurrences of iron
ore in the Dharwárs, particularly in the Kunchur tract southIron.
west of Hadagalli. Amongst the crystalline or gneissic rocks, several large and important bands of
pot-stone were examined in the Harapanahalli area. The Pot-stone.
most extensive band occurs at Nilgunda, seven miles to the west-south-west of Harapanahalli. The rock is often fine-grained and homogeneous enough for architectural carving; but no particular development of the finer steatitic form was noted.
Other occurrences are reported, which will, however, be described in detail in Mr. Foote's forthcoming memoir on the Bellary district. The very numerous and great runs or walls of fault-rock traversing the crystal
line area are a conspicuous feature in the Bellary country ; Fault-rock; cuprife.
1ee though, contrary to expectations, they are only rarely metal.
thong rous at times.
liferous, and then usually with iron ore to a poor extent. In the great 12-mile dyke or ridge north of Harapanahalli, however, the numerous interstices of the rock are locally filled by films of rich green carbonate of copper. At one place, on the slope of the ridge near the Nandi Bevur-Itugi road to Bellary, are two old open workings from which the ore had been raised in some quantity n times of which there is no recollection or tradition now.'' CENTRAL PROVINCES.-- Lower Gondwana. Although there is now no Survey party
. in this division of Peninsular India, the Department has not Chhattisgarh - coal thrown off all connection with any future development of fields. Ib coal.
the Chhattisgarh coal fields.' Renewed interest has been aroused, by the striking of a seam of coal in the foundations of a bridge over the Ib river during the progress of construction of the Bengal-Nagpore Railway, though much importance was not attached at first to this find, because that part of the country had already been surveyed and tested by a series of borings which pierced several thick seams of coal and carbonaceous shale of too inferior quality to encourage further exploitation. ..
The Ib bridge find was, however, followed by the digging of a small pit; whence a reported trial of the coal gave such favourable results that arrangements were made for me to visit once more this field, in which I had myself failed to strike any sufficiently promising seams. This small pit furnished continuous samples of 8 feet of apparently uniformly good coal, on which I advised as to a system of boring should any of these samples be favourable ; but, after all, even this coal was found to be not of much better quality than that already known in the field. Still, its uniformity and thickness are in its favour; and, above all, it was certainly better than the coal then being used on the railway from the Warora colliery. Several other borings have been put down by the railway authorities, but it is doubtful as yet whether this particular seam has been met with again ; while a very thick seam, purporting to be all coal, of some 40 odd feet in thickness, has been struck quite near the surface. No samples of this thick seam have yet Leen sent down to the Survey for examination; but it will prob
ably turn out that much of it is only carbonaceous shale, and that it is the same seam which I had already tested at Ghanamal near the broad exposure in the Lillari river. In the meantime, one of the two sets of American steam-boring plant sent out to
this Department by Her Majesty's Secretary of State has been Utilization of the Sur.'. Tor vey boring machines.
· lent to the Bengal-Nagpore Railway Company for further
exploration. There can be no doubt of the almost illimitable quantity of coal in this field, but nothing more can be reckoned on as to its quality than that it may in places be better than the Warora coal; all the good samples I have seen, with the exception of the Ib bridge, being only from thin bands associated with a preponderating thickness of poorer fuel or useless carbonaceous shale. It still remains to find a fairly uniform thickness of coal in the seam answering to that struck in the small pit at the Ib bridge. BENGAL PRESIDENCY.–Lower Gondwana.-Renewed enquiry having been insti
tuted as to the capabilities of the Western Bengal coal fields, Messrs. La Touche
uche in view of the construction of a line of railway between
in u; and P. N. Bose.
Howrah and Moghulserai, the Daltongunj coal field has become the scene of fresh research. Towards the end of the year Mr. La Touche
most was deputed to the geological part of the work; that is, to Daltongunj coal. was a field. Utilization of se.. select sites for borings and trial pits, a series of which he has cond set of Survey bor. accordingly arranged. Active operations have been coming plant.
menced, while the second set of American boring-plant has been lent to the Department of Public Works for the furtherance of the work.
The trial borings in the Hura field of the Rajmahai tract near Semra have reHura coal field, Raj.
à Raie sulted in the abandonment of that exploration. I visited
sus mahal. Borings relin. the place in January last in company with Mr. Atkinson, quished.
: of the firm of contractors who had undertaken the work, and pointed out two sites of the set of three borings which were contracted for. Unfortunately, the operations were again and again delayed for a considerable time through loss of boring tools: the results being that two of the holes were run down to 142 and 300 feet respectively. The first failed utterly through the whole string of tools being lost in the hole, and no fresh hole in that locality has been sunk, although I had expected that such would have been carried out eventually. The second hole, further to the deep by 600 yards, was then run down 300 feet; and two coaly seams were reported as struck at 200 and 209 feet. The samples sent down yielded over 31 per cent. of ash, showing that the coal, such as it is, is unfit for fuel. The poor coals already struck in the previous borings in 1889 were all near the edge of the field; but it was to be expected that there might have been some improvement in the quality of any higher coalfurther from the edge of the field. The last boring has dispelled such anticipation. I am obliged therefore, however reluctantly, to come to the opinion that there would be no gain by prosecuting any further search by boring at this part of the western side of the Rajmahal country. During the past season Mr. Bose has steadily and successfully explored the
coal area to the southward of Kalimpong in the Darjiling Darjiling coal. Mr. P. N. Bose. district between district between
the Sisu and Ramthi rivers, a very
detailed report on which appeared in the Records of the Geological Survey of India for November last. A sum of Rs. 2,000 was sanctioned by the Bengal Government for the exploration ; and considering that Mr. Bose
he poor 31 perceed as stone
tested the ground by over a hundred shallow pits and trenches, coked the coal in the field, and opened paths and clearings in the exceedingly close jungle of this overgrown tract at the foot of the hills at an expenditure well within that sanction, the whole exploration was managed with admirable economy.
As a rule, the coal is very high dipping and much crushed, while faults are numerous : thus, the working of it will be very difficult and precarious. The quality of the coal is, however, good, and a great part of it can be coked. It would appear that there may be some 5 million tons available of good coal, while it is estimated that 20 million tons may be set down for the whole explored area of a little over one square mile.
Mr. Bose divides his coal into three classes-A, B, and C-of which A cakes strongly, the percentage of ash not exceeding 16, while B cakes strongly, and has between 16 and 22 per cent. of ash.
Of the principal coal seams, not less than 5 feet in thickness, as indicated by his pits, all belonging to classes A and B, he counts about 25; although his calculation for 51 million tons of coal is based only on 11 seams.
During the original enquiry after this Darjiling coal, when thin seams were known as occurring in the neighbourhood of Teendaria and other places, a very poor opinion was formed as to its capabilities, and the best that was thought of it was that it might be compressed into bricquettes. The later finding of seams of from 16 up to 27 feet in thickness was far too encouraging, however, to leave the utilization of the fuel an open question, to be tried merely by samples in the laboratory : so Mr. Bose took the opportunity of spending some days at the coking operations at the Sanktoria colliery near Barakar; while a small press was most obligingly lent him by Messrs. Burn & Co., of Calcutta. The pressing of the coal was a failure owing to some fault in the press; but the coking experiments, which were carried out in the field, in three open kilns of good size, were completely successful.
Thus far,—and that is as far as geologists can report on a coal field,—the survey of the Sisu-Ramthi area is finished : it remains for actual coal mining, which can of course be carried out best by colliery engineers with experience of high-dipping coal.
EXTRA-PENINSULAR INDIA. BALUCHISTAN.-Tertiary.--Mr. Oldham carried on the survey throughout the Mr. R. D. Oldham yo
year, and added very considerably to our knowledge of and Sub-Assistants the coal, oil and water resources in British Baluchistan. Hira Lal and Kishen Early in the year his work still lay in the Harnai valley, Singh.
and a special report on the more favourable sites for Petroleum explorations in the Harnai district was published in the May number of the Records, following on a general description of the mode of occurrence of the petroleum and his reasons for believing that it exists in workable quantities, which description appeared in the following number of the same publication. Three localities were indicated at Spintangi, Pir, and Kipar Mand; although,
taking all things into consideration, he is in favour of the Location of oil sites in the Harnai valley
second locality being adopted for the commencement of
exploration. In any case, the depth of boring would be very considerable, 1,000 feet or more, according to the situation, though this can hardly be considered a prohibitive depth in such close proximity to the line of railway.
I went over the whole ground with Mr. Oldham in March, and was struck with the remarkable display of shows of dried-up oil in the limestones of the particular localities pointed out, while all his reasoning and expectation thereon appeared to me to be fairly justified. There is, in fact, little doubt but that a large store of oil lies within profitable reach of this part of the Sind-Pishin railway. During his examination of the Bolan pass in February and March, Mr. Oldham
I was led to make the following remarks on the oil locality Bolan valley: oil.
near Kirta :-“At the foot of the hills west of the dâk bungalow there are extensive deposits of travertine which have evidently been deposited by hot sulphurous springs, which have now ceased to flow, though warm gas still oozes up through the travertine and can be recognized by its smell. It is difficult to say why these springs issued there: no certain indications of a fault can be found, and one of the springs issued formerly from the hillside, 250 feet above the top of the talus fan at its base. They occur along the outcrop of the band of sandy limestones and calcareous sandstones with belemnite-bearing shales at their base.
“These travertine deposits are impregnated to a marked degree by petroleum, and on the strength of these surface indications a bore-hole was sunk in the spring of 1889. It pinetrated the belemnite shales; and at 360 feet a copious spring of hot sulphurous water was struck, and a small amount of oil obtained. The derrick was shifted, but no second boring was put down.
"In view of the importance of discovering petroleum in workable quantity near the line of railway, it is important to discuss the probability of its so occurring near Kirta. A careful examination of the outcrops has convinced me that the petroleum which impregnates the travertine and surface soil was not derived from any rock now exposed at the outcrop, but was brought up from below with the hot water of the springs. Further, from the occurrence of an abundant supply of hot sulphurous water, which, when released by the bore-hole, flowed freely at the surface, it would seem that these springs have ceased to flow owing to their channels having been blocked up by a deposit of travertine. If this conclusion be correct, any boring sunk along the line of these old springs would be likely to be troubled with hot acid water, which would rapidly corrode the casing of the bore-hole.
“A bore-hole sunk further out in the valley might escape this trouble. On the other hand, it is impossible either to determine with certainty the structure of the beds underlying the valley gravels, or to give any estimate of the depth to which it would have to be sunk.” An important and somewhat hopeful result has been attained concerning the
occurrence of oil in the Sherani country, on the north-west Sherani country: oil.
e side of the Sulaiman range. • In the first instance, a small bottle was sent to the Department in January 1890, labelled “Sample of raw mineral oil, procured by Police Sergeant Shehr Dil Khan, from a place in the Sherani hills, called Terai, about a mile from the Chin Khey! village of Mogul Kot, 15 miles out of British territory. Forwarded from Dera Ismail Khan by F. Broadway, Esq., District Superintendent of Police, on the 2nd December 1889."
On being tested in the Survey laboratory, the sample was pronounced not crude, but a commercial kerosene oil of Russian origin.
Independent testing of another sample by Dr. Warden, Chemical Examiner to
the Government of Bengal, gave rise to even a more confirmed suspicion that the oil was a commercial article.
Subsequent enquiry resulted in a further sample being sent down to Dr. Warden in August last : a report on which was given by him, dated 30th September 1890, the penultimate paragraph of which is :-"Assuming this sample of oil to be what it is stated to be-crude petroleum, its value commercially, if it can be procured in sufficient amount, can hardly be over-estimated. A large supply of a natural oil of this quality would simply drive out all foreign oil from the market; there could be no competition."
Ultimately, Mr. Oldham was enabled to visit the locality during the late Zhob Valley Expedition, in November last. His preliminary report shows that the petroleum near Mogul Kot issues at several spots from a band of hard, unfossiliferous sandstone, probably of cretaceous age. The actual overflow of oil at the springs is probably small, not more than ten gallons a day. The oil is clear, limpid, of a pale-yellow colour, and, as it issues from the rock perfectly free from water. He considers there is no reason for doubting that the samples examined in Calcutta were genuine samples of the oil.
His general conclusions are that there can be no doubt of the existence of oil of excellent quality and great value in the district, but that it would be premature to undertake any expensive operations at present. • The sample sent down by Mr. Oldham has been tested in the Survey laboratory by Mr. T. H. Holland, who has furnished a full report : but his results do not supplement Mr. Oldham's estimate of the oil as favourably as might have been anticipated. He considers, after giving all details of the examination, that “as com. pared with other samples obtained from this district, the specimen sent by Mr. Oldham must be considered to be decidedly inferior in quality.” ...
The enquiry, therefore, cannot be considered otherwise than as yet but very preliminary; and it must remain so until a more thorough examination of the locality and its conditions can be carried out.
Exploration for coal in the Baluchistan region has been prosecuted in the Bolan valley, and in the hills east and south-east of Quetta. The coal seams of the Bolan are practically confined to the neighbourhood of
Mach; and, as in the Harnai valley, the limitation of the Bolan coal.
i distribution of the coal seems to be due to the original limitation of the conditions under which it would be formed. South of Ab-i-gum, nothing beyond an occasional exposure of carbonaceous shale or thin layers of coaly matter has been observed.
The coal exposures eastwards of Mach have long been known, and have been worked in a small fitful way for several years. A grant of land in the Hannar valley was made to Messrs. Beahan and Wright, and some drifts made by them in a coal seam gave the following section :