LOCATION OF OUTSIDE IMPROVEMENTS.
On this subject we shall be brief, not because of its insignificance, or that it can be intelligently discussed in a few words, but for the simple reason that nothing short of an elaborate discussion could present the importance of the subject in a comprehensive or valuable shape.
The outside improvements of our large colliery establishments cost from $50,000 to $150,000,—depending on the amount of business to be done, the character of the plan adopted, and the nature of the location.
It too often happens that a set plan, from which there is no deviation, is made to answer every type of location, ignoring entirely every natural advantage which may be offered, the consequent result being a vast addition to the first cost, and a continual disadvantage in the operation. The object to be accomplished is economy in first expenditure and future operation; but if both can be accomplished, it is the duty and business of the engineer to see it done. Therefore, while a general and tried system of improvements may be followed, the natural advantages or disadvantages of the location should be duly considered, and either be made use of or provided against. How this may be done can perhaps be best learned from seeing how it has been done,—not in any one locality, but in many localities. If all the improvements made use of at the various collieries throughout the anthracite regions could be blended in one, we might expect a model operation. It is scarcely possible, however, for this to be done; but we know of many mining establishments that would have been much more convenient and more economically worked with certain additions or alterations which we have seen elsewhere. We cannot point out those instances without invidious mention and comparison, and will, therefore, only call attention to the subject in general. But, in order to make clear our meaning on this subject, we will state an instance, to show how natural advantages may be made use of.
A colliery was erected on a comparatively flat seam of coal. It was found, however, that the seam dipped more rapidly towards the centre of the basin, and that it would require a deep shaft to reach it, and that, when reached, only a portion of the coal could be obtained conveniently by breasts, or where the dip was sufficient; and that above the brow of the dip could only be brought down by inclines to the bottom of the shaft ; or one portion of the mine—say 50 yards—above the shaft could be worked only by "breast and shutes," and the other portion—say 150 yards—could be worked only by " breast and cars." Still, the true mode of working this coal did not occur to the
management. The location of the breaking establishment was changed from a fine natural site to one presenting many disadvantages, and a shaft was sunk to the coal on one side of the breaker, and a tunnel driven on the other.
The distance to the brow of the dip was not over 50 feet across the measures; or a shaft 50 feet deep, at an angle of 50°, would have reached the seam at a point where a perpendicular shaft could not be sunk, on account of the face of the hill. This short, sloping shaft would cut the coal on the brow, where 150 yards of breast, or an average dip of 15°, existed, and which could be mined with cars in all the breasts with much economy. Now, let us see the difference in first cost. The perpendicular shaft is about 150 feet deep, costing at least $10,000 more than the sloping shaft would have cost; the tunnel cost $7000, and the additional cost of breaker and machinery more than would have been required by the former mode, not less than $10,000.
Thus, we have $27,000 as the increased cost by adopting this mode. The business done may be placed at 200 tons per day from the shaft, and the additional cost not less than ten cents per ton over what would have been the cost in case a sloping shaft was used, from the greater drainage, the greater elevation, and the inconvenience of mining under the complicated system inevitable in the case of a deep shaft.
If a sloping shaft across the measures had been adopted, all the coal could have been elevated direct to the top of the breaker ; but, by the plan made use of, the coal from both tunnel and shaft was elevated to the top of the breaker by independent machinery. Therefore, we think ten cents per ton a low estimate for the additional cost entailed on a business of 200 tons per day, and one which would last as long as the colliery at the present level, which cannot be short of ten years. Thus, we find this error of loca tion entailing not only a yearly expenditure of $6000, but limiting the business to a small capacity, besides necessitating the increase of the original capital and its interest.
There are many other instances of error in location which betray a greater want of experience and judgment than this, but we must let this one suffice for all.