The question of the rapid shipment of coal, with a minimum of breakage, is one of such vital importance to coal-owners, harbour authorities, and others, that the writer offers his experience of a new method of shipment with some confidence that it will prove of interest to the members. In doing so, he would venture to submit that a change from existing methods is so much to be desired, that every encouragement and facility should be given by those interested for the promotion of improved methods.

That the problem of improved methods of shipment is a very difficult one is proved by the continued existence of methods which are the same to-day as they were 50 years ago. The methods in general use are, so far as the writer is conversant with them, of the following descriptions :—

(a) The drop, in which the coal-waggon with bottom-boards is lowered against a balance-weight down to the level of the ship's hatchway and there discharged en masse by releasing the bottom-boards, the coal falling a distance varying from the full depth of the hold to the reduced distance consequent upon the heaping up of the coal in the hold.

(b) The spout, in which the coal is discharged from the waggons at a high level and gravitates down an inclined spout or shoot to the ship's hatchway, where it is controlled by a trap and is discharged into the ship, falling a similar distance to that which obtains in the case of the drop.

(c) The crane, in which the waggon is lifted on a cradle by hydraulic, steam, or other power from quay-level, and is swung round and discharged at, or occasionally a little below the combings of the hatchway.

(d) The hydraulic crane, in which the waggon is run on to a cage or platform, elevated to a shoot, and there discharged, the coal gravitating down the shoot to the hatchway, as in the case of the spout arrangement.

In addition to these systems, there are modifications of the general arrangements described in occasional use, and there are also several exceptional arrangements which represent the attempts which have been made to deal with the subject on a new basis. These attempts, in all instances which have come under the writer's observation, are so modern, and the result is so difficult to judge, that there is no generally pronounced opinion that any one system has effected a very marked improvement upon the older systems. Whilst this is so, however, there is little doubt that, although the results have not been generally acknowledged, in several of the modern attempts which have been referred to, causes of breakage have been removed, which must tend to reduce the breakage and to improve the condition of the coal.

Adverting to the systems generally in use, the writer is of opinion that the most desirable of the old arrangements, in so far as saving of breakage is concerned, are the drop and the crane, as in both these arrangements two causes of breakage are absent which prevail in other arrangements, viz., the discharge into a spout and the attrition of the coal in the spout. Both arrangements, however, lack that rapidity in shipment which is demanded, and in both there is also serious breakage of the coal until shipment has proceeded to a stage where the waggon can discharge on to a heap, with less fall than that to which it is subjected in the earlier stages of shipment.

With regard to speed of shipment, it may be taken for granted that no system is acceptable unless it fulfils the demand of the ship owner for rapid despatch and it is to be feared that this demand stands more than anything else in the way of improvements in the methods of shipment so far as breakage is concerned.

Before describing the arrangement of belts which is the subject of this paper, it seems desirable to summarize the points which tend to the breakage of coal in existing systems. The chief causes of breakage in shipment are :—(1) The fall from a waggon into a shoot, the fall being increased by the angle of inclination of the shoot ; (2) the attrition of the coal in the shoot and the breakage caused by impact of coal on coal as it slides down the shoot, especially if the trap be neglected ; and (3) the fall of the coal from the hatchway into the ship.

The following is a description of the Wrightson coal-shipper :— As shown by the accompanying plans (Figs. 1, 2, and 3, Plate II), the machine is constructed with two conveying-belts A and B, and one vertical belt C fitted with trays a, which lower the coal into the hold. The first belt A is carried horizontally upon a frame which forms the basis and foundation of the machine.

At the end of the belt A, an upright frame D is socketed in the centre, at the bottom b, into the frame and at the top into another socket or bearing c carried by stays, the arrangement resembling that of the mast and stays of a derrick-crane. The second belt B works as a jib from the pivoted frame, and is supported at its outer end by ropes, wound on to two drums E fixed on the pivoted frame D. On the end of the jib-belt B, and hung on a centre attached to the frame of the belt, is the trunk or vertical belt C. The entire machine is mounted on wheels, and can be run away from or towards the ship as required.

All the movements are obtained from an engine F of semi-portable type, which is seated on the back of the machine, the power being conveyed by a horizontal shaft d and a vertical shaft e, from which all the movements are derived by suitable chain or gear-wheels. The motion of the vertical trays a is transmitted by the links of the conveying-belt B, and by chain-wheels from the outer drum-shaft f, to the drum-shaft g and the vertical belt C.

By an ingenious arrangement, the vertical shaft e is placed concentric to all the movements of. which the jib is capable.

The movements conveyed from the engine are as follows :—(1) The machine may be travelled in and out, to and from its work; (2) the conveying-belts A and B can be put in motion; and (8) the jib-belt B may be put into motion or may be raised or lowered, or swung horizontally, with a range of 9 feet on each side of its centre — i.e., with a total lateral range of 18 feet. All these movements may be made simultaneously, or separately, as desired, by means of clutches on the various movements.

In working, the belts A and B are geared to different speeds, for the purpose of obtaining a regular distribution of the coal into the trays a on the trunk-belt C. The belt A is driven at 40 feet per minute, the jibbelt B at 60 feet per minute, and the trunk-belt C at 80 feet per minute.

The waggons are brought in at a high level, and discharge from the bottom into a hopper, the bottom of which is formed by the plates of the belt A. This hopper has been made of such size that, when a waggon of coal is discharged, the coal chokes the hopper, and consequently the fall to which it is subjected is minimized. The coal leaves the waggon, after choking on the heap, at such a speed as the speed of the conveying belt A permits, the depth of coal on the belt being regulated by a fixed trap on the outside of the hopper. This trap permits the belt to load to a depth of 18 inches. The coal is carried along the belt A in a stream 4 feet wide by 18 inches deep, the jib-belt B being set to suit the ship, and with the trunk-belt C placed in the hold, the stream is continued on to the jib-belt B, and from it delivered on to the trunk-belt C.

The possible causes of breakage to which the coal is subjected from the time it leaves the waggon are :—(1) in discharging from the waggon to the hopper ; (2) in being transferred from the first belt to the jibbelt ; (3) in being discharged from the jib-belt on to the trunk-belt; and (4) in being discharged from the trunk-belt on to the heap in the ship's hold.

The conclusions which the writer has formed from observation of the working of the machine over several months are as follows :—(1) In discharging from the waggon on to the belt, there is necessarily some breakage, but this is minimized when compared with the hopper connected with an ordinary shoot by the shallow hopper with a level bottom. The coal appears on the first belt with no apparent change in its condition, although there must of necessity be some alteration. (2) In being conveyed along the first belt, all the damage caused by the friction and rolling in a spout, and the damage caused by improper manipulation of the trap is avoided. (3) In changing from one belt to another, there is no apparent breakage, the coal flowing quietly from one belt to the other in a steady stream and without apparent fall. The condition of the coal on the jib-belt is apparently identical with its condition on the first belt. (4) In delivering from the jib-belt into the trunk, a fall is inevitable and damage occurs; this can be traced, to a certain extent, in the appearance of the coal in the trunk as compared with its appearance on the jib-belt. (5) In discharging from the trunk into the hold, the coal is poured on to the heap with a very slight fall, and no appreciable damage is sustained. (6) In the writer's opinion, which is formed from watching many ships while loading and some discharging after their voyage, there is considerable improvement in the condition of the coal as compared with the old system of spout-shipping.

In putting the first of a cargo into a ship, the wholesale breakage which is occasioned by the fall from the spout is avoided. The coal which is subjected to this treatment forms a considerable portion of the cargo, and the first of it (in discharging into the hold from a spout) is broken to dust. A considerable quantity of duff is also formed during the whole course of the shipment by the rubbing of the coal on the shoots, and a considerable part of the damage due to these causes is manifestly avoided in the belt-system.

The machine is now working as it was first designed and constructed, and up to the present time no alterations have been made in the original design, although experience has pointed to many possible improvements. Schemes for these are under consideration, but they need not be referred to further at present.

The machine was adopted by the directors of the Cramlington Coal Company as a serious attempt to deal with the breakage of their coal in shipment, and it has so far realized expectations that they intend to continue it and to endeavour to perfect the system.

The quantity which can be removed by the present machine has been found to be a 4 tons waggon in 30 seconds, or at the rate of 480 tons an hour. With a wider belt and a greater depth of coal, both of which are quite practicable, there would be no difficulty in removing even larger quantities.

The present arrangement of gangways has up to the time of writing this paper been inadequate for supplying more than 230 tons an hour to the machine, and it is at present in course of alteration to enable the waggons to satisfy the capacity of the machine. It is, therefore, amply demonstrated that the question of rapidity of shipment does not arise, and with regard to the lessening of breakage, the writer is of opinion that the machine is upon the right lines for solving a very difficult problem.