On Coal, with reference to its screening, transport, &c

Front matter

ON COAL WITH REFERENCE TO ITS SCREENING, TRANSPORT, &c. By FRED. CHAS. DANVERS, jJ Assoc. Inst. C.E., Assoc. Soc. Tel. Eng., of the Public Works Department, India Office, and Late Member of Council of the Society of Engineers, London. " I am really concerned for the honour of Coal ; it is an interesting subject, " especially in India; and, as very little relative to what is herein recorded has " been said about it hitherto, that I know of, I reckon the subject my own, " and therefore I wish to be its faithful historian."— Paraphrased from a " Natural History ofthe Mineral Kingdom, 1789." PRINTED BY ORDER OF THE SECRETARY OF STATE FOR INDIA IN COUNCIL. LONDON: Wm. H. ALLEN & CO., 13, WATERLOO PLACE, S.W. 1872. METCHIM & SON, 20, parliament street, S.W., AND 32, CLEMENT'S LANE, E.C.

Preface

. The importance of economising our Coal resources has only been forcibly recognised within the past few years, and the voluminous Report by the Coal Commission recently published sets the whole question of Coal Economy before the public in a more complete and comprehensive manner than had previously been anywhere attempted. That Report, however, deals principally with waste iu working and waste in consumption, so far as the direct question of economy is concerned, but it does not directly deal with the many considerations by which Coal is affected between the Colliery aud the place of its ultimate destination, such as " Screening," " Transport by Railway and Canal," "Storeage," Shipment," &c, all of which are most important subjects in connection with the great question of Coal Economy. With the exception of the last-named, these subjects do not appear ever to have received the serious consideration they deserve of those who have before taken up the investigation of questions connected with our Coal supplies, and the present Work has there fore been prepared with the view of affording information concerning them.

This treatise on " Coal Economy" was commenced with the view of forming the subject of a Report to the Indian Government. It has now been approved and ordered to be printed by the Secretary of State for India in Council, for circulation in India; but the importance of the subjects dealt with ajipears also to warrant its publication in this country, and, from the opinions expressed by those to whom the manuscript was submitted prior to publication, to justify the expectation that the information collected would form a not altogether invaluable addition to existing publications more or less relating to " Coal Economy." F. C. D

Chapter I

Introductory. Importance of the Subject — Fuel for Indian Railways — Manufacture of Iron in India — Economy of Fuel — No published information existing on the Subject — Determination to make investigations into it — Time limited, and enquiries therefore confined to South Wales and Northumberland — The Colliery — Methods of Mining not investigated — Treatment of Coal at the Pit's mouth — Amount of small Coal left below, and brought to bank — Loss in small Coal made after reaching the surface — Screening — Softness of Indian Coal — Utilization of small Coal — The Heapstead — Collieries visited — Railways on which Coal is carried — Mineral Railways — Main Lines — Unloading of Trucks — Depots for Coals — Canal carriage — Delivery into barges — Loading and unloading of vessels — Ports visited — General Observations.

Having for some years past taken particular interest in the development of the Indian Coalfields, that subject appears to me to have attained considerably increased importance since the determination was made by Government to undertake the construction of a system of State Railways throughout India. As the length of open line increases in India so must the question of fuel supply for the locomotives, and other services in connection with railway working, increase in importance. If the manufacture of iron be ever introduced into India to any extent, and if, as it is to be hoped may be the case, provision be made for re-rolling the railway bars in India, as they become worn out, then it is clear that the continuous increase in the demand for fuel, for the above purposes alone, must in future years progress at a very rapid rate, to say nothing of the demand which will most probably increase in a similar ratio for other purposes of commerce and manufacture.

It does not appear probable that any amount of forest conservancy will ever suffice to secure a supply of wood fuel that will render India independent of her coal supplies. There exists no reason for supposing that in this respect India will form any exception to other B countries where coal has been found, for it has been the invariable rule that with an increase of serviceable coal supply the demand for fuel has so extended that the use of wood alone becomes impossible. It is stated in Mr. Juland Danvers' Report on Railways in India for 1870-71, that " A regular system has been organised in the Madras Presidency for obtaining an adequate supply of wood fuel for railway purposes. It has been estimated that nearly one hundred square miles will be required to meet the demand, &c." This alone will give some idea of the extent of country that would have to be devoted to the purposes of growing fuel for railways, and which might probably be more profitably devoted to the growth of grain, if the demand should increase in any rapid proportion ; for it must be borne in mind that an increase of traffic on a railway causes an increase in the consumption of fuel, and that for every additional ton of merchandise carried so much extra fuel is expended.

The railways of the United Kingdom now run over 12,803 miles, and the quantity of coal used by them, for locomotives and for other railway purposes, amounts to 2,027,500 tons in the course of the year." The length of railway now open in India is a little in excess of 5,000 miles, but the traffic being less, a proportional amount of fuel to length of line is not now required; the number of train miles run being 139,647,569,f and 14,396,7904 in England and India respectively. The beds of coal worked in India having, until quite recently, been confined to the Ranigunj district, the use of Indian coal for railway purposes has necessarily been very limited, but the rapid increase in the quantity raised is somewhat remarkable; "with some fluctuations, the amount of coal raised in India has, during the eleven years, from 1858 to 1868 inclusive, steadily increased from 61^ lakhs of maunds in 1858 to 127^ lakhs of maunds in 1868.

In other words, the quantity has con siderably more than doubled during the lapse of ten years. If we go back still further, we find that in 1850 the total quantity sent away from the Ranigunj field was * "Report of Coal Commissioners, 1871," vol. 3, p. 204. t Printed Parliamentary Paper (c. 229) of 1870. J "Report on Indian Railways, 1870-71." lakhs of maunds; while in 1868 this out-turn had grown to 126 lakhs, or nearly six times the amount. Few industries can point to such an extension within the same number of years." * With the development of the coalfields recently discovered in the Central Provinces, it may well be anticipated that the quantity of coal raised in India in future years will continue, for some time to come, to increase very rapidly. So far as railways are concerned, it is unquestionable that the demand for fuel must annually increase in India; and it may not be altogether out of place here to remark, that by the use of a rotary puddling furnace recently introduced in America, the principal difficulties in the way of iron manufacture in India may be successfully overcome.*)" Should my anticipations in this respect be fulfilled, there will at once be opened up a new industry in India, for which a very large supply of fuel will be required.

Professor JervousJ has pointed out that, although, according to the mechanical theory of heat, the work done by coal in a good engine ofthe present day does not exceed about one-sixth part of what the coal is capable of doing, any improvement for tlie purpose of economising its power is not likely to be accompanied by a corresponding reduction in consumption. " It is wholly a confusion of ideas," he says, " to suppose that the economical use of fuel is equivalent to a diminished consumption. The very contrary is the truth." If a diminished demand for coal then, is not to be looked for as a consequence ofthe introduction of improved and more economical means of using it, the same amount of fuel may be made to go further by the introduction of improvements in the means of getting it in the first instance, and in the haulage * " Coal Commissioners Report, 1871," vol. III., p. 233. t I refer to Danks's Patent Rotary Furnace, a paper on which was read at a recent meeting of the Iron and Steel Institute at Dudley, at which I was present.

So favourable an opinion was entertained by the members of the Institute, of the value of this invention, that they sent out a Commission to America to make further enquiries concerning it, who have since reported most fully in its favour, and puddling furnaces on Danks' principle are now being put up by several leading iron masters in England. X " The Coal Question," W. S. Jervous, 1866, p. 123. B and transport of it in the second ; or, in other words, by the avoidance of waste. Although an immense amount of information exists relative to the getting of coal, and a few papers have been published relative to the shipment of coal, I have been able to discover no published books or papers what ever that would throw any light upon the important questions of the " screening," " transport," " haulage," and " storeage " of coals.

Being impressed witli the conviction that information on these points would be of great use for genera] information, but more particularly for India, where coal mining may be said to be yet in its infancy, I resolved last year to investigate various questions embraced under the several headings above mentioned. As the time at my disposal was, however, not sufficient to admit of my visiting all the principal coal fields in England, I determined, after seeking advice on the subject from several competent authorities, to limit my present investigations to the coalfields in South Wales, and about Newcastle, as I was assured that, after visiting those districts, I should probably have seen all the best and newest appliances in use in England. Thus, whilst my enquiries may be said to have been, to a certain extent, only limited in the extent over which they have been conducted, so far as regards questions con cerning the delivery of coal from the mouth of the pit, I have reason to believe that I should have gained very few additional items of information had I extended my investigations to the Lancashire and Midland coal districts.

By reference to the Coal Commissioners Report, Vol. I. Page ix., it will be seen that the South Wales coal-bed is the largest, and, with the exception of the Midland coal bed, which i-anks second in importance, the Northumber land and Durham coal-field is the next largest. For the special object of my enquiries, however, I was advised to visit the Northumberland rather than the Midland district. My investigations at the colliery were with reference to the treatment the coal receives from the moment it emerges from the pit's mouth; more particularly with reference to the mode of screening and delivery into wagons ; but I have purposely omitted any allusion to the working ofthe coal underground, as that is a subject which has repeatedly, and most fully, been treated of by others more acquainted with the subject, and therefore better qualified for the purpose than myself.

The amount of small coal made in working, and the quantities of it left below and brought to bank respectively, have, however, received my particular attention, as well as the extent of deterioration which the coal undergoes during the several processes through which it passes, prior to arriving at its destination for consumption. My enquiries on this latter question may, to a certain extent, be considered as an extension of the investigations undertaken by Committee C, appointed by the Coal Commission to report on " waste in working." A great deal of most valuable information is contained in the evidence given before that Committee/"" showing; an amount of waste which is equivalent in reality to a great national loss, for under favourable svstems of working the loss is estimated at about ten per cent., while in a very large number of instances the ordinary waste and loss amounts to forty per cent.f My recent inquiries not only enable me fully to corroborate the above statement, but I am prepared to show that the loss in many instances is considerably greater than is there stated.

The foregoing refers, however, only to the loss in working, but after being raised, coal undergoes a further continuous depreciation in every stage through which it is passed until it finally arrives at the point of its ultimate destination. Thus, waste of coal through breakage is occasioned by delivery down a shoot, and still more so by the process of screening, for, as will be found in a subsequent portion of this report, the more coal is screened, the more small is got out of it by the breakage of the coal in passing over the screen, and it is unquestionably a fact, as was remarked to me during my visit to Swansea, " if you only had a screen long enough all the coal would pass through, and none would ever reach the bottom of it." I believe the practice of screening, to the extent to which it is adopted in South Wales, is particularly destructive, and it is a some what curious fact that whereas the steam coal of South Wales has to undergo numerous screenings, that of the * "Coal Commissioners' Report, 1871," vol. IL, p. 313 to 412. •j* " Coal Commissioners' Report, 1871," vol. I., p. 9.

Newcastle district, which would not suffer so much from the process, is, as a rule, scarcely screened at all. This question of screening becomes therefore an important one for India, where much of the coal is of a very soft character, and it is one to which I have consequently devoted a considerable amount of attention. In addition to the loss made by screening, the shaking of the coal in railway wagons during its conveyance from the colliery, causes further breakage, and its delivery from the wagon, either into ships or into depot, is, even when the greatest possible care is exercised, and the best known appliances and machinery employed, invariably attended by a still further depreciation in the amount of large coal ulti mately available for use as " round coal." Again, with very soft coal, such as that obtained from the Mayo Pit, at Chanda, exposure to the atmosphere causes it to dis integrate to a certain extent, occasioning thereby a still further loss of serviceable coal.

It will therefore be seen that, even with the greatest care, a very large amount of coal is depreciated, if not actually destroyed, in addition to the loss made in working. My attention has, for some time past, been particularly given to the question of how to utilise this small coal, which is now too often wasted. In Northumberland I have seen railway lines ballasted with coal, and some small railway embankments con structed apparently, entirely with small coal, whilst at almost every pit's mouth are to be seen heaps containing thousands of tons of what might be converted into valuable fuel. In Chapter VI. this question is dealt with more fully, and I shall, therefore, say no more on it now. The arrangement ofthe "heapstead," or " pit bank," as the head works of a colliery are technically called, appeared also to be deserving of a little consideration and attention, as the economical working of a colliery pit must depend, in a measure, upon all the appliances used in connection with it.

In this respect I have found various practices prevailing in different parts, which will be more fully described in another chapter. The collieries at which I have gathered information especially for the purposes of this paper are, in South Wales, the Powell's Duffryn, the Nixon's Dufiryn, and the Nixon's Navigation Collieries at Mountain Ash, and Blamgwawr Colliery, belonging to Messrs. David Davis and Sons, at Aberdare. In the northern district, the Hilda Colliery, at South Shields; Ryhope Colliery, at Sunderland ; Cambois Colliery, near Blyth ; and the Barrington and Bedlington Collieries near Morpeth. With reference to railways and the haulage of coal, my investigations have reference to the permanent way, weight of rails, speed of trains, locomotives, rolling stock, maximum weight of trains, and rates charged for carriage.

Not the least important amongst my enquiries has been the question of break of gauge, as that is one which will shortly arise in India, when narrow gauge lines shall have been constructed to connect the Central Provinces coalfields with the Great Indian Peninsular Railway. Fortunately there has been some experience on this point in England, for at one time, before the narrow gauge was laid down on the Great Western Railway between Wolverhampton and London, coals bad to be transhipped at the former place from narrow into broad gauge wagons. I have taken great pains to collect all the information obtainable upon this head. It may be said that, for coal traffic, two classes of railway exist, and the present paper would have been incomplete had my enquiries been limited only to one of them. There is, first, the mineral line, leading direct up to the several collieries, and carrying little else besides coal, and the great main lines of railway over which coal is conveyed from the mineral lines to the principal centres of industry along their respective routes.

In the former case, the railway is laid out with special reference to its coal traffic, the conveyance of passengers being only a secondary consideration. To this class, it is presumed, the contemplated line from Chanda would most properly belong; and as, with the discovery of new coal fields, other lines of a similar character will be required, I have thought it of sufficient importance to make most minute enquiries into the construction and working of such lines in England. For this purpose I selected the TafiF Vale Railway in South Wales, and the Blyth and Tyne Railway in Northumberland. The second class of railway to which I have referred, on which there is a large coal traffic, consists of those main lines which would correspond with the existing arterial lines in India, and their future probable extensions.

With these, wherever there is a large passenger traffic, the goods trains must of course give way to the passenger trains. Although the East India Railway is not unac quainted with coal traffic combined with passenger traffic, I have thought it desirable, with a view to render my present paper complete, to institute enquiries into the mineral working of our main lines of railway, and I have accordingly collected my information, under this heading, from the following railways, yiz: — The Great Western, The North Western, The Midland, The Great Northern, The Great Eastern, and The North Eastern. Immediately connected with the latter class of raihvays is the question of unloading railway trucks, and deposit ing coal iuto the great central depots for town consump tion. Very great improvements have of late years been made in the arrangements of urban depots, and some very extensive buildings have quite recently been erected in London for the purpose, in which are embodied all the improvements that experience has shown hitherto, can be adopted for the purposes of economy and expe dition.

The principal coal depots about London are those at Hackney, Holloway, Camden Town, Kentish Town, Caledonian Road, Agar Town, Shoreditch, Elephant and Castle, and Wai worth Road, particulars of which will be found in the following pages. As a rule, these depots are employed solely for the storeage of coal used for domestic and other town purposes, steam coal for vessels being usually emptied into barges in London, and so conveyed by means of canals to the Thames, excepting when such steamers happen to be in dock, and facilities exist for running the coal trucks direct on to the quay, when special machinery is employed, which will be separately noticed presently. During the process of delivering coal into depot, a considerable amount of " small" is separated from it, showing that since leaving the pit a further process of deterioration has been going on, and, although in the vicinity of large towns there is plenty of demand for small coal for brick burning and other manufacturing purposes, the price that it commands is considerably less than what can be obtained for round coal, and the loss of money to the coal merchant on the former article has, of course, to be made ap by an increase of charge on the latter.

Thus, the public have to pay, in the long run, for the breakage of coal in this, as in all other stages through which it has to pass; and any economy that can be obtained in this respect, by the introduction of improved means of trans port, or by the application of better mechanical appliances for the loading and unloading of coal into wagons, barges, ships, or depots, may fairly be regarded as so much addition to the available mineral fuel wealth of the country. If the above proposition may be considered a fair one with respect to this country, where we have coals of every degree of hardness, how much more will it apply to India, whose coal resources, as at present dis covered and worked, produce a fuel of a very tender and friable nature? Although canal carriage for coal has now been almost entirely superseded by railways, there nevertheless are certain circumstances under which the latter cannot convey coal to its ultimate destination, when barges can be employed for the purpose, and taking into consider ation the existence of numerous canals in India, leading to districts where railways will probably not find their way for many years to come, but where coal, if obtainable, would be eagerly sought after, and that others, such as the circular canals about Calcutta, may he economically employed for the distribution of coal, I have thought it desirable to collect such information as w7as available relative to the loading and unloading of barges writh coal.

With very few exceptions, barges for coal traffic are hardly to be seen in the colliery districts which I have recently visited, but a not inconsiderable trade is carried on, in this way, in and about London. The only other question to which I have given attention, for the purposes of this paper, is the loading and unloading of colliery vessels, and the filling of the bunkers of steamers with coal. So far as the loading of vessels with coals for transport is concerned, it is not probable that much will be required for India in that direction for many years to come, but the supply of fuel for steamers is a question already of every day importance, in India as much as anywhere else, where numbei'less river steamers, as well as ocean steamers, must constantly require to replenish their coal bunkers.

It seemed, therefore, that the present paper would be incomplete unless the subject were introduced, and full particulars given of the appliances in use for the purpose, at the different principal shipping ports in this country. It is true that information on this point has been already published to a certain extent, but nothing appears to have been written on the subject for some years past, and the improvements that have taken place in the machinery employed, within the last few years, have not so far as I have been able to ascertain, been recorded in such a manner as to make the information available to the public. The following remarks relative to this section of my paper are founded entirely upon personal observation on the spot, and wherever I may have found it desirable to borrow from the reports of others, the papers quoted from will be found mentioned in a foot note.

The ports visited for the collection of information on this head were, in South Wales, Swansea, Cardiff and Newport, and in the North, Newcastle and the Tyne Docks. In drawing up the following paper two points have been constantly borne in mind. Firstly, that in the absence of any previous publication treating on the several questions above mentioned, the information contained in the following pages will, it is hoped, be found to be of interest to all connected with the getting or sale of coal. The Coal Commissioners have, in Committee C, collected a vast amount of most valuable information on " Waste in Working," but their enquiries have been confined ex clusively to underground working, whilst my investigations have commenced where theirs left off, and I have endeavoured to trace the amount of waste, or more properly speaking, the amount of small coal made during tlie subsequent stages which coal has to pass through before arriving at its ultimate destination, and this, it will be seen, is a question only second in importance to that which has been investigated in Committee C. In drawing attention to this most important subject, two considera tions naturally suggest themselves, viz.: 1.

How is this waste to be reduced ? and 2. As under any circumstances, a certain amount of loss must arise from breakage, how can the small coal be best utilized ? There can be but little difficulty in replying to the former question. As the amount of breakage varies in the same coal, by the use of different appliances, so it will only be by the introduction of the most approved machinery that any diminution will be effected in the amount of small coal made. The necessity for offering every possible encouragement for the introduction of improved machinery and appliances will at once be apparent when it is pointed out that assuming the difference in the value between round coal and small coal, at the pit's mouth, to be only Qs. 8d.* the national loss occasioned in 1869 by every five per cent, of small coal made upon the total quantity retained for home con sumption will have amounted to no less a sum than £1,617,775.

As will be seen, however, in the following pages, the loss on this head considerably exceeds five per cent., but what the average might be for all the coal raised my enquiries have scarcely been sufficiently extensive to enable me to form any reliable estimate. The utilization of small coal is a question entirely distinct from the former, although dependent upon it to a certain extent, and will be found treated on in a subsequent chapter. Secondly. In taking up this question, the importance which the several points possess in respect to India appeared to me sufficient reason for undertaking my recent enquiries. With the opening up of new coal fields in India it is highly important that the best means and appliances should be introduced for working them economically in the first instance, with a view to avoid that waste which has already cost this country many millions sterling by the destruction and depreciation of a large proportion of her mineral wealth, and, by the neglect of possible and well known precautions, this waste is daily being continued in connection with many English collieries; there is also too much reason to fear that no satisfactory efforts will be made to put a stop to this great national loss until the subject is taken up in a decisive manner by Parliament. * Six and eightpence is a very low figure.

I have found the difference in price, during my recent enquiries, vary from 6s. 6d. to as high as 8s. per ton, and at some places where there is no demand for small coal, it may almost be had for anything you like to offer.

Chapter II

At the Colliery. Small Coal made by " long wall," and "pillar and stall" systems of mining — Small Coal from Steam Coal and Bituminous Coal seams — The " separation " and " altogether Coal " principles — Amount of small Coal raised — Modes of paying the Collier — Analysis of Coal raised in one day from collieries on the two principles — Colliery Trams of various sizes — Advantages of Small Trams — Cages for raising the Trams — The Heapstead — The Pit-bank — The Weighbridge — Position of the Screens — Dimensions and forms of Screens vary in different districts — Distance between the Screen bars — Rocking Tables at head of Screens — Breakage of Coal on the Screen — - Balanced Screens — They do not really save the Coal much, if at all — " Billy play-fair" — Register of small Coal raised — Considerations as to the cause of so much disintegration in Coal before it leaves the Colliery — Proper angle for Screens — Collection of small Coal where no " Billy-play-fair " is used — Illustrations of different kinds of Screen — Utilization of small Coal — Manufacture of Coke — Juke's Furnace — Burning Coal dust — Patent Fuel — Separation of small Coal into " nuts," " peas," and " duff" — Description of Screen for small Coal division — Value of different sized small Coal — Importance of economising Indian Coal — Duty of Indian Coal — Consumption in Locomotives on Indian lines.