March 9, 1917.

493

THE COLLIERY GUARDIAN.
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ENGINEERING SPECIFICATIONS
AND COAL.

“ Some Points in Connection with Engineering Speci-
fications,” was the subject of a discussion at a meeting
of the Manchester section of the Institution of Elec-
trical Engineers last week.

In opening the debate, Mr. J. Shepherd read a paper,
in the course of which he dealt with “ coal ” as one of
the salient features of a number of recent specifications.
In a large generating station, he said, having a good
load factor, efficient turbine units, good superheat and
condensing conditions, and coal at normal prices, the
generating costs per unit might be taken to be as follow :
Salaries and wages, 0’030d.; coal and ashes, 0-160d.;
oil, waste, and stores, 0-004d.; repairs to plant and
buildings, 0’012d.—total, 0'206d. Goal and ashes thus
represented 78 per cent, of the total-, namely, out of
every' sovereign spent *n the station, 15s. 6d. was
required for the supply of coal and the removal of ashes,
excluding, for the moment, questions of capital charges.
With the present high prices of coal, the proportion was
now even higher. With such high costs, the desir-
ability of buying coal cheaply was apparent. A buyer
with free power to purchase in the open market, and
with plenty of storage capacity for the coal when pur-
chased, would probably buy most cheaply by picking up
“spot lots ” where available, and especially at or near
a port; but, of course, such conditions did not apply at
the present time. When buying by contract, some form
of scientific specification was necessary, where locality
and circumstances allowed a free market; and the speci-
fication he intended to.describe was framed with a view
to buying coal in that, manner. As over one million
tons had been purchased in that way, it might be said
to have proved itself useful by the only true test, namely,
experience. Roughly, the specification might be said
to contain and set out :—

Quantity required, viz., 165,000 tons per annum.

Minimum quality to be accepted, viz.,

Calorific value not less than 11,000 British thermal
units.

Moisture must not exceed 14 per cent, for washed nuts,
or 9 per cent, for unwashed nuts.

Small coal must not exceed 30 per cent.

Ash must not exceed 15 per cent.

Delivery by steamer, and the berthing conditions are
also set out.

Methods of sampling were given in detail, but in later
specifications the .final sampling was done by a motor-
driven crusher and sampler. Methods of testing were
then specified, namely :—

(a)	For small coal, through a sieve with a mesh f in. sq.

(b)	Calorific value by Mahler bomb calorimeter.

(c)	Moisture after drying at a temperature of from 104

to 111 degs. Cent.

(d)	Ash determined by ignition at a low red heat.

When -tendering, the contractors are requested to state
both the price and the values offered of the following
particulars :—■

(a)	Calorific value -in British thermal units.

(c) Moisture in percentage by weight.

(e)	Small coal percentage by weight.

(g) Ash percentage by weight.

Those values must not be inferior to the minimum
values allowed. The specification provided for the
adjustment of the price paid for any particular cargo in
accordance with the values actually obtained for that
cargo, the -adjustment being made as set out below :—

Should the quality of the coal in any cargo, as ascertained
by samples tested, be found different, as regards calorific
value, moisture, small, or ash, from the values offered in the
schedule, the prices or sums payable as aforesaid shall be
varied in the manner following, viz. :—

(a)	If the calorific value be greater than the number of
British thermal units per pound offered in the schedule, the
price per ton shall be increased in the same percentage
ratio as the increase in the calorific value.

(b)	If the calorific value be less than the number of
British thermal units per pound offered in the schedule,
the price per ton shall be decreased in the same percentage
ratio as the decrease in the calorific value. Provided always
that the council shall have the right to reject the whole
cargo if the calorific value be less than 11,000 British
thermal units per pound.

(c)	If the moisture be less by weight than the figure
offered in the schedule, the weight of the coal to be paid for
shall be increased beyond ffie quantity actually weighed
out by a percentage equal to the percentage decrease of
moisture.

(d)	If the moisture exceed by weight the figure offered
in the schedule, the weight of the coal to be paid for shall
be decreased below the quantity actually weighed out by a
percentage equal to the percentage increase of moisture.
Provided always that the council shall have the right to
reject the whole cargo if the moisture exceed 14 per cent,
by weight for washed nuts, or 9 per cent, by weight for
unwashed nuts.

(e)	If the proportion of small coal in either singles or
doubles be less by weight than the figure offered in the
schedule when determined in the manner set out in clause
No. 10 of this specification, the weight of the coal to be
paid for shall be increased beyond the quantity actually
weighed out by a percentage equal to one-quarter of the
percentage decrease of small coal.

(J) If the proportion of small coal in either singles or
doubles exceeds by weight the figure offered in the schedule,
when determined in the manner set out in clause 10 of this
specification, the weight of the coal to be paid for shall be
decreased below the quantity actually weighed out by a
percentage equal to one-quarter of the percentage increase
of small coal. Provided always that the council shall have
the right to reject the whole cargo, if the proportion of small
coal exceeds 30 per cent, by weight.

(g) If the percentage of ash when determined in the
manner set out -in clause No. 10 of this specification be less
than the figure offered in the schedule, the net rate per ton
of coal shall be increased by Id. for every 1 per cent, reduc-
tion in ash.

(k) If the percentage of ash when determined in the
manner set out in clause No. 10 of this specification be
more than the figure offered in the schedule, the net rate
per ton of coal shall be reduced by Id. for everv 1 per cent,
increase in ash. Provided always that the council shall have
the right to reject the whole cargo if the proportion of -ash
exceeds 15 per cent.

The adjustment, he went on to say, might appear
somewhat cumbrous, but in practice it was not found to
be so. As an example, he submitted the details of an
actual invoice :—

Cargo of Scotch Nuts.

Weighed on delivery 1,447 tons 10 cwt.

Values offered
in tender.

20%

9%

12,500.

10%

Values determined
by analysis.

Small 14’70 %

Moisture 13’45 %

Cal. val., 13,070 B.Th.U. ...

Ash .	8’53%	...

Basis price for quality teniered 15s. lOd. per ton.

Coal as weighed............

Deduct for 4’45 % moisture ...

Difference.

+ 5’3

- 4*45

+ 579 = 4’56 %
+ 1’47%

Tons. cwt. qrs.

1,447 10	0

Add for calorific value 4’56 %
Add for ash l’47d. per ton ...

Add for small .j (5*3) = 1’325 %

61	8	1
1,383	1	3
19	3	2
1,402	5	1 at 15s. lOd. =
		£ s. d.
		1,110 2 6
			 50	12 5

8 17
_________

4

£1,169 12 3
Note price at net rate of 15s. 10d.,i.e, 1,447 tons

10 cwt. at 15s. lOd. would have been ... _____ <£1,145 18 9

Bonus on the cargo ..............................	£23 13 6

The reasons for the adjustment of prices w7ere fairly
obvious. They varied directly as the calorific value,
and inversely as the percentage of moisture. As regards
small coal, for each 4 per cent increase the rate w-as
diminished 1 per cent. The ash wTas indirectly allowed
for by diminished calorific value but'-a further penalty
of Id. per ton for each 1 per cent, increase over the
standard figure v-as deducted to cover the cost of con-
veying the ashes away by barges. As the coal tendered
by different- contractors might, and usually did, vary in
value, the rates per ton offered could not be directly
compared without adjustment to a common basis of
“ standard coal,” wffiich, for the purpose of comparing
tenders, wms taken at: Small 20 per cent.; calorific
value, 12,500 British thermal units; moisture,. 9-per
cent.; ash, 10 per cent.

After the comparison had been made and the tenders
awarded, all further adjustments for payment were made
in a similar manner to the examples he had given. The
volume of business dealt with by specification of the
character described was 100,000 tons in 1906, increasing
year by year to 160,000 tons in 1915. That necessitated
the removal from the boiler house of from 10,000 to
16,000 tons of ashes per annum. ’The coal usually pur-
chased’ under these specifications was Scotch washed
nuts shipped from various ports on the Firth of Forth,
and Yorkshire washed nuts shipped from Goole. The
Yorkshire coal had the higher calorific value, but wdieii
burnt under water tube boilers it was. found to be more
destructive of the brickwork sealings, a factor W’hich the
specification did not,. of course, allow for. If the
recovery of by-products became practicable in a power
station, modifications -in ihe specification for coal would
no doubt become necessary to suit the nitrogen contents
of the fuel. In passing, it might be remarked that a
specification for fuel was somewhat unique, having
little analogous in the ordinary run of civil engineer-
ing or architectural practice. The specifications had
enabled purchases to be made in the open market for
the past 10 years without giving rise to a single dispute
as to the value of the coal determined on delivery, and
for which the price was adjusted on the determination.

In his general remarks, the author stated that the
basis of all contracts depended upon much besides the
wording of a specification, and implied fair and reason-
able dealing on the part of both the supplier and pur-
chaser, without haggling on the part of the supplier, or
needless complaint or meddling by the customer’s engi-
neer. To the specifications he had described, coal, lay-
ing cable conduits, sub-station switchgear, re-construc-
tion of motor generators, etc., over 2-J- million pounds
worth of work had been purchased, and of that large
sum not more than £1,500 w7as spent .abroad, and that
w'as for articles wffiich were not manufactured in this
country. In the past, a large amount of. foreign pur-
chasing had taken place, resulting in the foreign manu-
facturer frequently escaping rigid inspection, burden-
some general conditions, exacting wage rates, and other
labour conditions. That state of affairs was not, how7-
ever, likely to be repeated during the next 10 years, nor,
it was to be hoped, for a much longer period.

In the course of the discussion, Mr. Robertson
remarked that those who had been trying to get coal
during the last two years coked upon the idea of pur-
chasing upon a heat basis, or calorific basis, as a kind of
vision which was quite unattainable at the present time.
Indeed, they were glad to get any kind of coal, and wise
enough not to question whether its calorific value was
up to the. standard, or whether the percentage of ash
was high. Speaking with some knowledge of the dis-
trict, he was afraid that state of things, w’ould continue
for some time to come. The principle of purchasing on
a calorific basis was, no doubt, quite right, but it would
be necessary to get the market properly educated up to-
il before it became a general practice. Some years ago
he did purchase coal in Scotland on that basis, the pro-
ducers accepting clauses, similar to those given in the
paper, which set forth how7 the price was to vary with
the calorific value. I
that way, an agent approached him with an offer to
•supply any quantity of coal from the same pits in cer-.
tain proportions at 9d. per ton less than the colliery

BOOK NOTICES.

An Introduction to Mine Surveying. By Thomas Bryson
and George M. Chambers. 288 pp.; 7| in. x 4f in.;
111 fig. London : Edward Arnold. Price, 5s. net.

This book has been written for surveyors and students
of coal mining, the authors being certificated colliery
managers, and otherwise excellently qualified for the
task of writing a text-book of this character. The object
aimed at is to provide an elementary handbook for
Students’ use. Its -scope is -such as to ensure qualifica-
tion for the serious candidate at any of the ordinary
examinations in surveying. A particular feature has
been made of plan drawing, not only of the mine, but
also of the position of underground workings with rela-
tion to the surface. The book is' arranged to cover a
tw'o years’ course, and importance is attached to the
order in which the chapters are arranged. The book
shows clearly the hand of the practical teacher. We
thoroughly agree with the views of the authors relating
to finished drawings. It is true that the more closely
the candidate’s plan at an examination resembles the
wx>rk of the trained surveyor, the greater will be the
measure of his success. It is, however, a fundamental
weakness of most examination time-tables that the
candidate has but little time for embellishing his work;
but he. should nevertheless know how . to do so. A
useful feature of the book is a collection of 138 exer-
cises, with answers to the calculations. To work con-
sistently through these should be productive of much
confidence and lability to deal with any ordinary pro-
blem. The amount of mathematical knowledge required
for the purpose of an intelligent study of this text-book
is not more than might be expected of those students
who aspire to become practical surveyors. The book
can be thoroughly recommended for the purpose for
which it is designed. We should be inclined to predict
that it will be widely appreciated by mining students.
Mineral Duties on Land Values. By R. F. MacSwinney,
barrister-at-law. 42 pp.	8 J in. x.5^-in. London:

Sweet and Maxwell Limited. Stiff covers, price 4s.
net.

This may be described as a concise supplement to the
fourth edition of the author’s legal text-book on mines.
When that edition w-as published, there had been no
legal decisions under the provisions relating to mineral
duties in recent Finance Acts, that is to say, the
Finance Act (1909-10), as amended by section 11
of the Act of 1912, section 43 of the Act (No. 2) of
1915, and section 46 of the Act of 1916. Now, as the
author states, there have been a sufficient number to
simplify some of the complexity and lighten some of
the darkness which he finds inherent in taxing Acts.
These decisions have accordingly been dealt with in the
form of notes to the enactments, and are published
separately. Special attention is given to Foran’s case,
and to Inland Revenue v. Sheffield.

Depreciation and Wasting Assets. By P. D. Leake, F.C.A.,
etc. 84 in. x 5| in. pp. xxiv. + 233. London : Sir
Isaac Pitman and -Sons. Price, 10s. 6d. net.

Experience as a chartered accountant in connection
with industrial and other undertakings has impressed
upon Mr. Leake the importance of substituting for the
'haphazard methods, which he considers to be much too
prevalent, a more systematic treatment of the element
of depreciation and wasting assets in the estimation of
profit and loss. As the champion of more scientific
methods, he has become a recognised authority on a
question which, in a sense, he has made his own, and
which has strong claims from the point of view of the
higher accountancy and a strictly accurate balance-
sheet. This volume is not his only contribution to the
subject, but it is the most comprehensive; and the fact
that the publishers venture on a second edition in these
times seems to indicate that the book has arrested the
__............._ ___ __ ,	__ attention of those to whom it was addressed. Some of

After buying for several years in these may consider that Mr. Leake is not altogether
an agent approached him with an offer to free from the tendency of the specialist to exaggerate
1 p J1 - ----------------------- — the importance of his proposals, but in the many com-

mercial and industrial developments of recent years he

proprietor’s agents were offering it at, provided the
calorific value clause was taken out of the specification.
As coal at that time was about 9s. or 10s. a ton, 9d.
per ton was a consideration, and he assented. For six
months he tried it almost every day, and the results
were quite satisfactory. He quoted that instance to
show that if severe conditions were introduced into speci-
fications, the colliery people,.or the agents, must put a
margin on the price to cover the risk taken under that
clause.

Mr. Shepherd, in the course of his reply to the dis-
. cussion, said it w’as an extraordinary thing that coal,
of which there was an output of something like 300
million tons per annum in this country,- was really the
only material that was practically all sold without
analysis. In the case of other minerals, or ore, the
material was carefully analysed after delivery, and the
next purchase based upon the results. But in purchas-
ing coal they bought a black-looking commodity, which
they trusted would burn, and in which the moisture
might vary from 4 to 15 per cent. It had been said
that they bought nine buckets of coal and a tenth bucket
, of moisture. Why. should they do that? If they made
a claim against the coal merchant, they generally found
if they got fid. from him, the next time he tendered they
were fined that 6d. Perhaps the better way was to pay
for the bucket of water, and allow for a reasonable
amount of water when doing so. He did not agree that
the percentage of moisture varied according to whether
the coal was delivered by steamer or by rail. Coal put
into a steamer w’as carefully weighed at both ends of the
journey, and the difference in the weights was 1 to
per cent., whereas the moisture in the Yorkshire coal
might be as high as 14 per cent.

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