Delay at the
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"Sunshine Mines"
How Delays at Opencast Coal Sites Affect Haulage Rates. Demurrage Charges Justified Where Congestion is Serious
THE old and vexed question of demurrage came to my mind in reading through a schedule of haulage rates for opencast coal agreed between the Road Haulage Association and the Ministry of Transport. Table I shows these rates revised in accordance with an agreement that the originals should be increased by 10 per cent. In the figures shown in Table I, therefore, there is provision for a 10 per cent, addition to the rates as published in the first place.
In arriving at a schedule of rates of this kind, some agreement must have been reached as to the probable periods of delay at the loading and unloading end of each journey. That information not being provided, it seemed to me that it might not be a bad thing to find out what would be the maximum delay period which would allow these rates to show a profit.
The first thing to do, of course, is to get at the operating cost of the vehicle involved. I have assumed, as experience has shown me to be justified, that the vehicle employed will be a 6-ton tipper, and in Table II I have set out figures of cost for such a vehicle. Before proceeding, it is of interest to note that in this table I have provided for the penny per gallon increase in the price of petrol which became current on Monday, September 1.
Minimum Charges On the basis of an allowance of 20 per cent, for profit, the minimum charges which should be made for the use of this vehicle must be 9s. 7d. per hour; that is, 8s.. plus onefifth of 8s., Is, 7d., and 6/d per mile, which is 5.60d., plus 1.12d., making actually 6.72d. In taking a figure of 6/d., therefore, I am giving the haulier the benefit of 1-33d. for every mile.
Now in the previous set of figures which I gave for the operating cost of a vehicle.of this kind, the fuel cost was 3.00d. instead of 3.14d., and the total running cost per mile was 5.46d. instead of 5.60d On that occasion. adding 20 per cent, to the 5.46d., which is 1.09d., I arrived at a total of 6.55d. and took 60., so that on that occasion 1 gave the customer the benefit of 1-20d. per mile. An interesting point is that, taking those give-and-take fractions of a penny into consideration, the increase of Id. per gallon in the price of petrol has involved an increase of Id. per mile in the charge which the haulier must make.
Now, to assess the rates which should be charged on the basis of these time and mileage charges of 9s. 7d. per hour and 6/d. per mile.
Every operator will agree that the most satisfactory method, from his point of view, is to assess. the potential number of journeys per week and take that as a basis for calculating the rate. We have a 44-hour week, consisting of four days in which nine hours are worked and a fifth day of eight hours, and part of the problem which I am about to try to solve is to assess the number of journeys which can be accomplished in a week, so arranged.
In assessing the journey time, I again make the following assumptions, which have appeared before in similar articles. It should be appreciated that I am considering a vehicle at liberty to travel at 30 tn.p h.
The first half-mile in each direction will be covered in five minutes at an average speed of 6 m.p.h., so that for a onemile lead the time taken will be 10 minutes each way.
What is going to be the provision for loading and unloading time? As a preliminary, I propose to take the absolute minimum, insisting, at the same time, that such provision is hardly practicable. I shall take a quarter of an hour at each end.
The lorry is assumed to run under the chute at the opencast delivery depot with no loss of time and to have the coal delivered. The vehicle is then weighed, a tally given for the weight of the coal, and it then proceeds on its journey to the delivery end, where, on arrival, the tally is checked and the driver told where to tip the coal. A quarter of an hour at each end is a reasonable minimum.
, A Matter of Time
Now, for a one-mile lead we have for the total time 20 minutes, as set out above, plus 30 minutes for terminals. That means 50 minutes per journey and the maximum number of journeys per day of nine hours will be nine and of eight hours eight, a total of 44 journeys per week. The time charge for the week's use of the vehicle is 44 times 9s. 7d., which is £21 Is. 8d.
• In running the 44 journeys, of a mile each way, the vehicle will cover 88 miles, and the charge for that, at 61d. per mile is £2 9s. 6d. The total charge must therefore he £23 I Is. 2d.
The load carried is 6 tons on each of 44 journeys, which is thus 264; this divided into £23 Ils. 24., is about Is. 9d.
During the second half-mile in each direction, the vehicle may be assumed to travel at an average speed of 15 m.p.h. and will take, therefore, two minutes for each half-mile, four minutes for the mile, and eight minutes for the second mile of the journey in each direction. Altogether, for the two-mile lead, there will be a total of 28 minutes' travelling.
Observe that it is still theoretically possible to complete a journey within the hour, so that there again will be 44 journeys per week. The cost for time will be, as before, £21 Is. 8d., but this time the vehicle has covered 176 miles at 61d., which is £4 19s. The total charge will therefore be £26 Os. 8d. and that is 2s. per ton for the 264 tons carried.
The third mile of any distance will be run at an average
speed. of 24 m.p.h., and the mile will take 21 minutes. The total for the three miles each way will thus be 20 minutes, plus eight minutes, plus five minutes, which is 33 minutes in all, and the time for the complete journey, including terminals, will be at least three minutes over the hour.
It will not, therefore, be practicable to run nine journeys in a nine-hour day, or eight journeys in an eight-hour day, without overtime, and in practice it will be found that, during the nine-hour day, eight runs will be made and during the eight-hour day seven. That would mean 39 journeys per week, but as there is such a narrow margin, there is just the possibility of an extra journey being run, and I will assume that 40 journeys can be covered in the 44 holm.
This time the mileage per week is 240 and the cost at 61d. per mile is £6 15s. The total charge is thus £27 16s. 8d. and the tonnage carried 240. That means that the rate must be very nearly 2s. 4d. per ton,
A Paradox
Before going further, it is of interest to observe that these rates are below those which appear on the schedule, the difference being 6d. or 7d. per ton. That, as will be seen before I have completed the article, is something which can quite easily be accounted for. For the time being we will let it go at that and try out one or two more distances.
For every mile beyond the three-miles lead, the vehicle is assumed to travel at 30 m.p.h., so that four minutes extra is the time requisite for each additional mite lead. A mile lead involves, of course, two miles of running.
For a four-mile lead the travelling time would be 37 minutes and the total for the journey 1 hour 7 minutes. This time I shall take eight journeys per nine-hour day and seven per eight-hour day, making 39 in all, and on this occasion I do not propose to imagine that an extra journey will be squeezed in. We thus have 39 journeys in the week, a total of 312 miles, with a total tonnage of 234.
The cost of 312 miles at 61d, per mile is £8 15s. 6d., to which, as before, we add £21 Is. '8d. for the 44 hours, giving a total of £29 17s.• 2d., and, for carrying 234 tons, that is equiValent to a rate of very nearly 2s. 7d. per ton, again 6d. below the standard figure: Proceeding on these tines, I have calculated that the rate for a five-mile lead 'should be 3s., for a 10-mile lead 4s. 4d., for a 20-mile lead 7s. 5d.
Coming to the 40-mile lead, we are in the position of having either to waste a lot of time or work a tittle overtime. If no overtime be worked, then it would be possible only to work 10 journeys per week, and the minimum A36 charge would be 14s. 6d. if, however, the man works 11 hours' overtime on each of the four nine-hour days, then 14 journeys can be completed in the week at a cost of about £55 and a rate of approximately 13s. For a 50-mile lead I arrived at a figure of 16s. 6d.
Now, it so happens that I have visited several of these opencast coal-distributing depots recently, and I am quite certain that at none of them would it be possible to comply with the times above quoted for collecting the coal. In the very best example I saw the time was half an hour at the collecting end and in the worst the delay was upwards of three hours at the collecting end.
What I propose to do now is to assume a minimum average delay of three quarters of an hour at the collecting end, but still adhering to the quarter of an hour at the delivery end and let us see how that alteration in time affects our journeys and the charges which should be made.
Effects of Delays
Beginning again at the one-mile lead and applying these new conditions, we get the time for a round journey to be 1 hour 20 minutes, one hour for terminals, 20 minutes for travelling. In those circumstances it will be possible to complete seven journeys per 91-hour day; that is to say, there will be seven journeys for each of four days, making 28, and six journeys on the eight-hour day, but on each of the four days there will be half an hour's overtime.
The cost, making provision on the same basis as before for time and mileage, with a little extra for the overtime, will work out at 2s. 3d. per ton for the 204 tons which will be carried on the 34 journeys during that week.
Over a two-mile leaJ the total time will be I hour 28 minutes, and it is sufficiently accurate to call that 11 hours. There will thus be six journeys per nine-hour day; that is, 24, plus five on the fifth or eight-hour day, making a:total of 29 journeys, during which the vehicle will run 116 miles and carry a total of 174 tons. There will be no overtime, so that the cost will be that of 116 miles at 6id., which is £3 5s. 3d., plus £21 Is. Sd. for the 44 hours of the vehicle time, a total of £24 6s. 11d. The charge for 174 tons to bring that revenue must be 2s: 91d.
On a three-mile lead the time is rather more than 1+ hours per journey, being precisely ,l hour 33 minutes, according to the above calculations, so that provision will again have to be made for a little overtime in. order to complete six jour-' neys in the nine-hour day. On that basis the charge for the conveyance of 174 tons, running 174 miles, will be 3s. Id. per ton.
There is no point in going into detail with the remaining mileages. It will be enough to say that, with this provision for an hour's terminal delays, the rates which I arrived at by means of these calculations are more or less the same as those of the R.H.A. If anything, there is a tendency for them to be a little higher. I should imagine, therefore. that that is approximately the provision for terminal delays made in assessing these rates.
The difference which terminal delays may make can be calculated roughly, that.is without going into detail about the number of journeys per week, by taking the 9s. 7d. as the rate for the hour and dividing it by six for the tonnage carried. It can be seen that a diffzrence of, say, 1s. 7d. per ton should by rights be debited against the customer for whom the coal is being carried.
Operator Stands the Loss
In present circumstances, the operator has to stand the loss. On the basis of 20 per cent, profit, that means that, unless he is carrying for a rate something in excess of 8s., he is actually losing money on every load he carries, and even above the 8s. rate he never makes anything like a reasonable profit for his work.
There is justification, to my mind, for a demurrage charge of 10s. an hour for any delay in excess of three-quarters of an hour at any opencast coal-distributing depot. Where delays are excessive-as they certainly are in some placessteps should be taken to debit the Coal Board with that amount of extra cost.
As an alternative, it might then happen that those responsible for what is called the organization of transport at these depots will be persuaded to take a little more care to see that the lorries are not called until there is coal for them to collect. S.T,R.