coal trade bulletin - Clpdigital.org

When unsupported, the roof of the working
places in the No. 9 seam presents a great hazard
to the life of the workman. Only by careful in­
spection and thorough propping can accident be
avoided. As the workings approach the crop lines
the liability of accident becomes even greater,
the black slate cover here shows marked ten­
dencies toward disintegration.
In No. 11 seams, the gob roof between the coal
and the limestone, is even more hazardous than
the slate roof of No. 9. After the coal has been
shot down, the gob will overhang the working
places in thicknesses varying from 4 to 30 inches.
Being exceedingly treacherous, it will work down­
ward from the limestone cover without warning
and fall with a thunderous crash on whatever
happens to be below.
It is customary with one of the largest opera­
tors to work pick miners in entries where the
CHAHACTER (It THE KOOI
is such as to necessitate propping, too close for
the operation of coal cutting machines.
Several companies operating in other seams
have still more difficult roof conditions to contend
with. The strata overlaying these coals consists
of from 10 to 15 feet of light gray shale, which
is in advanced stages of disintegration.
On removing all the coal in these mines, the
shale will fall to heights of six to eight feet.
Twelve to 18 inches of coal is therefore
left overhead as a roof, of which 00 per cent, is
reclaimed in the rooms after they have been ex­
hausted. When the coal is mined to its full thickness
the rotton overlaying shale requires timber
sets, thoroughly and solidly lagged, to hold it.
In whatever entries are driven, no attempt is
made to reclaim this top coal.
The degree of caution exercised within the
mines of this field by superintendents and fore­
men is reflected by the following list:
During the year 1911, in the entire westein
Kentucky field there were only 3 fatal accidents
from falls of roof, and 19 minor or non-fatal ac­
cidents from the same cause.
A fair estimate fixes about two-thirds as the
net portion of the available coal measures which
is won from the mines. Superlative competition
in this field leaves so small a differential between
costs of production and the sales prices that crop
coal and coal of more expensive excavation must
be left untouched and forever lost.
With a decrease in the market price, the con­
sumer becomes more exacting and
MUCH COAL is WASTED
at the tipples in cleaning the product to make the
grades salable at even a small figure. Good coal
clinging to lumps of sulphur is often discarded
on the waste piles in quantities which more than
justify the lamentations of those sincerely in­
THE COAL TRADE BULLETIN. 45
terested in the conservation of our coal measures.
An instance of this. A large operator in this
field discovered that in satisfying the exacting
demands of his customers he was throwing away,
on the refuse pile at a single mine, coal which
if properly cleaned would have yielded him in
the neighborhood of $1,000 per month. This
shows that if there had been some means of
preparing the waste coal for use, provided that
the mine was operating on a very narrow margin
of profit, the net value would have done much
toward helping the balance on the credit side of
the ledger.
Another source of waste in this district is the
indifference with which some of our operators
plan the future development of their property.
On good authority, it is claimed that 50 per cent.
of the operators have no idea as to the amount
of their original holdings which they have ex­
hausted.
Coincident with (his is the general scarcity of
technically trained engineers.
Inadequate pillars also contribute to the gen­
eral waste. Frequently the smallness of pillars
results in a squeeze which necessitates the
abandonment of the working places. These rooms
must then be recovered by driving "cut-offs," ac­
companied by additional expense and the loss of
the coal which is left unmined.
It is taken for granted by most western Ken­
tucky operators that squeezing
GOES HAND IX HAND
with the mining of coal. It is regarded as a
necessary evil. It is looked upon as one of the
penalties of mining.
We have no definite data on the size of pillars
that are required by a given vertical thickness
of cover of a given character. Chief Inspector
Norwood is at the present time endeavoring to
secure government co-operation for the deter­
mination of these unknown quantities.
Operators working seams other than No. 9 and
No. 11, in several instances, find it wholly impossible
to recover more than 44 per cent, of
their available coal and are required by their
conditions to leave more than half of their coal
unmined.
Another question needing attention in this field
is that of cost keeping. It is perfectly safe to
say that 75 per cent, of the operators do not
know what it costs them to mine a ton of coal.
They get extensions on bills and buy equipment
on tho installment plan, which is altogether
within the limits of good management. But in
many cases these items are not charged off in
keeping with an accurate accounting system. At
the end of a given period they find their balance
on either one side of the ledger or the other, but
how it came about there is no telling.