Coal and the coal mines

Front matter

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REFERENCE LIBRARY OF HOUGHTON MIFFLIN COMPANY

2 Park Street, Boston

Preface

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In treating of so large a theme in so small a compass it is impossible to do more than make an outline sketch. It has been the aim of the author to give reliable information free from minute details and technicalities. That information has been, for the most part, gathered through personal experience in the mines. The literature of this special subject is very meagre, and the author is unable to acknowledge any real indebtedness to more than half a dozen volumes. First among these is the valuable treatise on “Coal Mining,” by H. M. Chance of the Pennsylvania Geological Survey. Other volumes from which the author has derived considerable information are the State geological reports of Pennsylvania, the mine inspector’s reports of the same State, and the “ Coal Trade Annuals,” issued by Frederick E. Saward of New York.

The author desires also to acknowledge his invl PREFACE.

debtedness for valuable assistance in the preparation of this work to John B. Law and Andrew Bryden, mining superintendents, and George Johnson, real estate agent, all of the Pennsylvania Coal Company, at Pittston, Pennsylvania, and to the officers of the Wyoming Historical and Geological Society of Wilkes Barre, Pennsylvania.

HOMER GREENE,

HONESDALE, Pa., May 15, 1889.

Contents

II. Toe ComposiTIon OF COAL . « « « « Ill. Wuen Coat was FoRMED ... .« -« IV. How rue Coat Beps Lie .....

VY. Tue Discovery or CoAL .... .» VI. Tue InrropvuctTion oF Coat into UsE VIL. Tae Way into THE Mines.... . VIII. A Puan or A Coat MinE .... IX. Toe Miner at WoRK. ...-. « « X. WHEN THE Mine Roor Farts... - XI. Arm anp WATER IN THE MINES. . XII. Tue Dangerous GASES . .. ss - XIII. Tae Anruracire Coat BREAKER . XIV. In roe Brrumrnovus Coat MINES. . XV. Tue Boy Workers AT THE MINES. .« XVI. MrineRS AND THEIR WAGES . « « « «

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Chapter I. In The Beginning

Every one knows that mineral coal is dug out from the crust of the earth. But the question frequently is asked concerning it, How and under what conditions was it formed? In order to answer this inquiry it is necessary to have recourse to the science of geology.

A brief review of the geological history of the earth’s crust will be of prime importance, and it will not be inappropriate to go back to the origin of the earth itself. But no man can begin at the beginning ; that is too far back in the eternal mists; only the Infinite Mind can reach to it. There is a point, however, to which speculation ean journey, and from which it has brought back brilliant theories to account for the existence of the planet on which we live. The most philosophic of these theories, as it certainly is the most popular, is the one known as the Nebular Hypothesis, propounded by Laplace, the great French astronomer, in 1796. This theory accords so well with the laws of physics, and with the human knowledge of the age, that most of the great - astronomers have adopted it as the best that has been given to us, and the world of science may be said to have accepted it as final. Let us suppose, then, in accordance with this theory, that our earth was, at one time, a ball of liquid fire, revolving on its axis, and moving, in its orbit, around the parent sun with the motion imparted to it in the beginning. As cooling and condensation went on, a crust was formed on its surface, and water was formed on the crust. The waters, however, were no sooner spread out than they were tossed by the motion of the atmosphere into waves, and these waves, by constant friction against the rock crust of the earth, wore it down into pebbles, sand, and mud. The silt thus made being washed up on to the primitive rock and left there by the receding waters became again as hard and firm as before. Occasionally a subsidence, due to the contraction of the earth’s body, would take place and the sea would again sweep over the entire surface, depositing another layer of silt on the one already formed, or possibly washing that again into sand and pebbles. This process continued through an indefinite period of time, forming layer upon layer of stratified rock, or exeavating great hollows in the surface already formed.

That period in the history of the earth’s crust

IN THE BEGINNING. 3 before stratification began is known as Archean time. This was followed by the period known as Paleozoic time, which is divided into three ages. The first is the age of Invertebrates. It was during this age that life made its advent on the earth. The waters were the first to bring it forth, but before the close of the age it began also to appear on the land, in isolated spots, in the simplest forms of vegetation. The next age is known as the age of Fishes, during which vegetable life became more varied and abundant, winged insects floated in the air, and great sharks and gars swam in the seas. Then came the Carboniferous age or age of Coal Plants, in which vast areas of what are nuw the Middle, Southern, and Western States were covered with low marshes and shallow seas, and were rich and rank with multitudinous forms of vegetation. But these marshes were again and again submerged and covered with material washed up by the waves before the final subsidence of the waters left them as a continuing portion of the dry land. It was at the close of the Carboniferous age that great disturbances took place in the earth’s crust. Before this the rock strata had been comparatively level; now they were folded, flexed, broken, rounded into hills, pushed resistlessly up into mountain ranges. It was at this time that the upheaval of the great Appalachian Range in North America took place. Following this came Mesozoic time, which had but one age, the age of Reptiles. It was during this age that the type of reptiles reached its culmination. The land generally brought forth vegetation, though not with the prolific richness and luxury of the Carboniferous age. Birds, insects, and creeping things were abundant, and monsters of the saurian tribe swam in the seas, roamed through the marshes, crawled on the sandy shores, _ and took short flights through the air. The last great division is known as Cenozoic time, and covers two ages, the age of Mammals and the age of Man. It was during the mammalian age that trees of modern types, such as oak, maple, beech, etc., first made their appearance, and mammalian animals of great variety and size, both herbivorous and carnivorous, roamed through the forests. True birds flew in the air, true snakes crawled upon the ground, and in the waters were whales and many kinds of fishes of the present day. But the marine monsters and the gigantic and ferocious saurians of an earlier age had disappeared. So the world became fitted to be the dwelling-place of the human race. Then began the age of Man, an age which is yet not complete.

Such, in brief, is the history of the earth as the rocks have told it to us. Without their help we could know but little of the story. Through all the periods of time and all the ages, they were being formed, layer upon layer, of sand and silt, of mud and pebbles, hardening with the pass-

COLUMNAR SECTION OF THE

S CRUST.

EARTH

IN THE BEGINNING. 5 ing of the centuries. But while they were still

_ soft they received impressions of the feet of birds and of beasts, they were marked by the waves and were cracked in the fierce heat of the sun, and their surfaces were pitted by the rain-drops of passing showers. Shells, corals, and sponges were imbedded in them; the skeletons of fishes and the bones of animals that walked or crept upon the land or flew in the air were covered over by them; they caught and held the drooping fern, the falling leaf and twig and nut; they closed around the body of the tree itself and buried it from sight; and as the soil hardened into rock, bone and shell, leaf and stem, hardened with it and became part of it. To-day we find these fossil remains, sometimes near the surface of the earth, sometimes hundreds or thousands of feet below it. We uncover them from the soil, we break them from the rock, we blast them out in the quarries, we dig them from the mines of coal and ore. It is by them and by the structure of the rock which contains them that we read the history of the earth, a history covering so long a period of time from the beginning of the stratification of the rocks to the age when man appeared upon the globe that no one has yet dared to reckon the millions upon millions of years which intervened, and give the result of his computation to the world as true.

Chapter II. The Composition Of Coal

Tue first question that would naturally be asked concerning the subject with which we are dealing is, What is coal ?

In reply it may be said that it is a mineral. It is black or brown in color, solid, heavy, and amorphous. The specific gravity of the average Pennsylvania anthracite is about 1.6, and of the bituminous coal about 1.4. There are four varieties of mineral coal, namely: anthracite, bituminous, lignite or brown coal, and cannel coal. To this list it would not be improper to add peat, since it partakes of most of the characteristics of mineral coal, and would doubtless develop into such coal if the process of transformation were allowed to continue undisturbed. The principal element contained in each of these different kinds of coaliscarbon. An analysis of an average piece of Pennsylvania anthracite would show the following chemical composition : —

Fixed carbon . ; ‘ 4 é . 864 Ash . : A : , : ‘ ‘ 6.2 Water. ; . s . j R 3.7 Volatile matter ‘ ‘ : ; é 3.1 Sulphur. ; : : . : : 6

THE COMPOSITION OF COAL. 7

The composition of the bituminous coals of Pennsylvania, as represented by the gas coal of Westmoreland County, is shown by analysis to be as follows: —

Fixed carbon ., .

Volatile matter Fs - » ; Paris y is: Ash . ; A ' : 5.4 Water 4 é ; . ‘ 1.4 Sulphur... : . 7 Total ° ° ° » e * ° 100

An analysis of 2oal from the Pittsburgh region would show its percentage of carbon to be from 58 to 64, and of volatile matter and ash to be proportionately less.

There is no strict line of demarcation between the anthracite and the bituminous coals. They are classed generally, according to the amount of carbon and volatile matter contained in them, as:—

Hard-dry Anthracites,

Semi-Anthracite,

Semi-Bituminous,

Bituminous.

Coals of the first class contain from 91 to 98 per cent. of carbon, and of the second class from 85 to 90 per cent. The volatile matter in the third class is usually less than 18 per cent., and in the fourth class more than 18 per cent. of its composition.

The anthracite coal is hard and brittle, and has a rich black color and a metallic lustre. It ignites with difficulty, and at first burns with a small blue flame of carbonic oxide. This disappears, however, when ignition is complete. No smoke is given off during combustion. Semi-anthracite coal is neither so hard, so dense, nor so brilliant in lustre as the anthracite, though when once fully ignited it has all the characteristic features of the latter in combustion. It is found principally at the western ends of the anthracite coal basins.

Bituminous coal is usually deep black in color, with little or no lustre, having planes of cleavage which run nearly at right angles with each other, so that when the coal is broken it separates into cubical fragments. It ignites easily and burns with a yellowish flame. It gives off smoke and leaves a large percentage of ashes after combustion. That variety of it known as caking or coking coal is the most important. This is quite soft, and will not bear much handling. During combustion it swells, fuses, and finally runs together in large porous masses.

Following the question of the composition of coal comes the question of its origin, of which, indeed, there is no longer any serious doubt. It is generally conceded that coal is a vegetable pro- — duct, and there are excellent reasons for this belief. The fragments of which coal is composed have been

THE COMPOSITION OF COAL. 9 greatly deformed by compression and decomposition. But when one of those fragments is made so thin that it will transmit light, and is then subjected to a powerful microscope, its vegetable structure may readily be distinguished ; that is, the fragments are seen to be the fragments of plants. Immediately under every separate seam of coal there is a stratum of what is known as fireclay. It may, under the beds of softer coals, be of the consistency of clay; but under the coal seams of the harder varieties it is usually in the form of a slaty rock. This fire clay stratum is always present, and contains in great abundance the fossil impressions of roots and stems and twigs, showing that it was once the soil from which vegetation grew luxuriantly. It is common also to find fossil tree-stems lying mashed flat between the layers of black slate which form the roof of the coal mines, also the impressions of the leaves, nuts, and seeds which fell from these trees while they were living. In some beds of cannel coal whole trees have been found, with roots, branches, leaves, and seeds complete, and all converted into the same quality of coal by which they were surrounded. In short, the strata of the coal measures everywhere are full of the fossil impressions of plants, of great variety both in kind and size.

If a piece of wood be subjected to heat and great pressure, a substance is obtained which strongly resembles mineral coal.

That coal contains a very large proportion of carbon in its composition has already been noted. If, therefore, it is a vegetable product, the vegetation from which it was formed must have been subjected to some process by which a large part of its substance was eliminated, since wood or woody fibre contains only from 20 to 25 per cent. of carbon. But wood can be transformed, by combustion, into charcoal, a material. containing in its composition 98 per cent. of carbon, or a preater percentage than the best anthracite contains. This cannot be done, however, by burning wood in an open fire, for in that case its carbon unites with atmospheric oxygen and passes invisibly into the air. It must be subjected to a process of smothered combustion; free access of air must be denied to it while it is burning. Then the volatile matter will be freed and expelled, and, since the carbon cannot come in contact with the oxygen of the air, it will be retained, together with a small percentage of ash. The result will be charcoal, or coal artificially made. The principle on which this transformation is based is combustion or decomposition out of contact with atmospheric air. But Nature is as familiar with this principle as is man, and she may not only be discovered putting it in practice, but the entire process may be watched from beginning toend. One must go, for this purpose, first, to a peat bed. This is simply an accumulation of the remains of

THE COMPOSITION OF COAL. 11 plants which grew and decayed on the spot where they are now found. As these remains were deposited each year, every layer became buried under its succeeding layer, until finally a great thickness was obtained. When we remove the upper layer we find peat with its 52 to 66 per cent. of carbon, and the deeper we go the better is the quality of the substance. It may be cut out in blocks with sharp spades, the water may be pressed from the blocks, and they may be stacked up, covered and dried, and used for fuel. In most peat bogs the process of growth is going on, and may be watched. ‘There is a certain kind of moss called sphagnum, which in large part makes up the peat-producing vegetation. Its roots die annually, but from the living top new roots are sent out each year. The workmen who dig peat understand that if this surface is destroyed the growth of the bed must stop; consequently in many in- _ stances they have removed the sod carefully, and after taking out a stratum of peat have replaced the sod in order that the bed may be renewed. There is little doubt that if these beds of peat could lie undisturbed and covered over through many ages they would take on all the characteristics of mineral coal.

A step farther back in geological history we reach the period of the latest formations of lignite or brown coal. This coal is first found in the strata of the glacial period, or first period in the age of Man. But it is found there in an undeveloped state. The woody fibre has not yet undergone the complete transformation into coal. The trunks and branches of trees have indeed become softened to the consistence of soap, but they still retain their natural color. Going back, however, to the strata of the Miocene or second period of the Tertiary age or age of Mammals, we find that this wood has become black, though it has not yet hardened. But when we reach the upper cretaceous or last period of the age of Reptiles, the transformation into coal has become complete. The woody fibre is now black, hard, and compact, though it may still be easily disaggregated by atmospheric action, and we have the true lignite, so called because of its apparent woody structure.

The next step takes us back to the bituminous coal of the Carboniferous age, the character and consistency of which has already been noted, and finally we reach the complete development in anthracite. It is, however, the opinion of the best geologists that the bituminous and anthracite coals are of the same age, and were originally of the same formation and character. That is, they were all bituminous ; but during the violent contortions and upheavals of the earth’s crust at the time of the Appalachian revolution at the close of the Carboniferous age, the bituminous coals involved in that disturbance were changed by heat, pres-

THE COMPOSITION OF COAL. 13 sure, and motion, and the consequent expulsion of volatile matter, from bituminous to anthracite.

Cannel coal is a variety of bituminous coal, burning with great freedom, the flame of which affords considerable light. It was called ‘candle coal” by the English people who first used it, as it often served as a substitute for that household necessity. But the name soon became corrupted to “cannel,” and has so remained. It is duller and more compact than the ordinary bituminous coal, and it can be wrought in a lathe and polished. A certain variety of it, found in the lower odlitic strata of Yorkshire in England, is manufactured into a kind of jewelry, well known by its popular name of jet.

Chapter III. When Coal Was Formed

Ir becomes of interest now to examine briefly into the causes and process of the transformation from vegetable substance into coal, to note the character of the vegetation which went to make up the coal beds, and to glance at the animal life of the period.

As has already been said, the plants of the Carboniferous age were exceedingly abundant and luxuriant. They grew up richly from the clayey soil, and formed dense jungles in the vast marshes which covered so large an area of the earth’s surface. Ferns, mosses, and tufts of surface vegetation, and the leaves, branches, and trunks of trees fell and decayed on the place where they grew, only to make the soil more fertile and the next growth richer and more luxuriant. Year after year, century after century, this process of growth and decay went on, until the beds of vegetable matter thus deposited had reached a great thickness. But condensation was still in progress in the earth’s body, and in consequence of it her crust, of necessity, at times contracted and fell. When it did so the land sank throughout vast areas, these beds of incipient coal went down, and over the great marshes the waters swept again, bringing drift of vegetation from higher levels to add to that already buried. Then over these deposits of vegetable matter the sand and mud and gravel were laid up anew, and the clayey soil from which the next rich growth should spring was spread out upon the surface. This process was repeated again and again, as often, indeed, as we find seams of coal inanycoal bed. Thus the final condition for the formation of coal was met, the exclusion of atmospheric air from this mass of decaying vegetation was complete, and under the water of the ocean, under the sand and silt of the shore, under the new deposits of succeeding ages, the transformation went on, the wood of the Carboniferous era became the coal of to-day, while above and below it the sand and clay were hardened into rock and shale.

The remarkable features of the vegetation of the coal era were the size and abundance of its plants. Trees of that time whose trunks were from one to three feet in diameter, and which grew to a height of from forty to one hundred feet, are represented in our day by mere stems a fraction of an inch in diameter and but one or two feet high. A comparison of quantity would show differences as great as does the comparison of size.

But at that time all the conditions were favorable for the rapid and enormous growth of vegetation. The air was laden with carbon, which is the principal food for plants; so laden, indeed, that man, who is eminently an oxygen-breathing animal, could not have lived in it. The great humidity of the atmosphere was another element favorable to growth. Vegetation never lacked for an abundance of moisture either at root or leaf. Then, too, the climate was universally warm. Over the entire surface of the earth the heat was greater than it is to-day at the torrid zone. It must be remembered that the internal fires of the globe have been constantly cooling and receding, and that the earth, in the Carboniferous age, was subjected to the greater power of a larger sun than shines upon us to-day.

With all these circumstances in its favor, warmth, moisture, and an atmosphere charged heavily with carbon, vegetation could not help but flourish. That it did flourish amazingly is abundantly shown by its fossil remains. The impressions of more than five hundred different species of plants that grew in the Carboniferous era have been found in the coal measures. There are few of them that bear any direct analogy to existing species, and these few have their counterparts only in the torrid zone. The most abundant of the plants of the coal era were the ferns. Their fossil remains are found in great profusion and variety in most of the rocks of the coal-bearing strata. There was also the plant known as the tree fern, which attained a height of twenty or thirty feet and carried a single tuft of leaves radiating from its top. Probably the species next in abundance, as it certainly is next in importance, to the ferns is that of the Lepidodendrids. It doubtless contributed the greatest proportion of woody material to the composition of coal. The plants of this species were forest trees, but are supposed to have been analogous to the low club mosses of the present. Fossil trunks of Lepidodendrids have been found measuring from one hundred to one hundred and thirty feet in length, and from six to ten feet in diameter.

Similar in appearance to the Lepidodendrids were the Sigillaria, which were also very abundant. The Conifers were of quite a different species from those already named, and probably grew on higher ground. They were somewhat analogous to the modern pine.

The Calamites belonged to the horsetail family. They grew up with long, reed-like, articulated stems to a height of twenty feet or more, and with a diameter of ten or twelve inches. They stood close together in the muddy ground, forming an almost impenetrable thicket, and probably made up a very large percentage of the vegetation which was transformed into coal.

One of the most abundant species of plants of the coal era is that of Stigmaria. Stout stems, from two to four inches in diameter, branched downward from a short trunk, and then grew out in long root-like processes, floating in the water or trailing on the mud to distances of twenty or thirty feet. These are the roots with which the under clay of every coal seam is usually filled.

The plants which have been described, together with their kindred species, formed the largest and most important part of the vegetation of the Carboniferous age. But of the hundreds of varieties which then abounded, the greater portion reached their highest stage of perfection in the coal era, and became extinct before the close of Paleozoic time. Other types were lost during Mesozoic time, and to-day there is scarcely a counterpart in existence of any of the multitude of forms of plant life that grew and flourished in that far-off age of the world.

The animal life of the Carboniferous era was confined almost entirely to the water. The dry land had not yet begun to produce in abundance the higher forms of living things. There were spiders there, however, and scorpions, and centipedes, and even cockroaches. There were also land snails, beetles, locusts, and mayflies. Reptiles, with clumsy feet and dragging tails, prowled about on the wet sands of the shore, leaving footprints that were never effaced by time or the elements, and are found to-day in the layers of the | rocks, almost as perfect as when they were formed, millions of years ago. But the waters teemed with animal life. On the bottom of the shallow seas lay shells and corals in such abundance and variety that from the deposits of their remains great beds of limestone have been formed. Broken into minute fragments by the action of the waves and washed up by the sea during periods of submergence, they were spread over the beds of carboniferous deposits, and became the rock strata through which the drills and shafts of to-day are sunk to reach the veins of mineral coal.

Fishes were numerous. Some of them, belonging. to species allied to the modern shark, were of great size, with huge fin spines fully eighteen inches in length. These spines have been found as fossils, as have also the scales, teeth, and bones. Complete skeletons of smaller fishes of the ganoid order were preserved in the rock as it hardened, and now form fossil specimens which are unequaled in beauty and perfection.

Besides the fishes, there were the swimming reptiles; amphibian monsters, allied to the ichthyosaurs and plesiosaurs which were so abundant during the Reptilian age that followed. These animals are known as enaliosaurs. They attained great size, being from twenty-five to fifty feet in length; they had air-breathing apparatus, and propelled themselves through the water with paddles like the paddles of whales. Their enormous jaws were lined with rows of sharp, pointed teeth, and their food was fish, shell-fish, and any other kind of animal life that came within their reach. They devoured even their own species. Living mostly in the open seas or fresh-water lagoons, they sometimes chased their prey far up the rivers, and sometimes basked in the sunshine on the sands of the shore. Frightful in aspect, fierce, and voracious, they were the terror and the tyrants of the seas. Such were the animals, such were the plants, that lived and died, that flourished and decayed, in the age when coal was being formed and fashioned and hidden away in the crust of the earth. That the fauna and flora of to-day have few prototypes among them should be little cause for regret. There was, indeed, hardly a feature in the landscape of the coal era that would have had a familiar look to an inhabitant of the world in its present age. In place of the hills and valleys as we have them now, there were great plains sloping imperceptibly to the borders of the sea. There were vast marshes, shallow fresh-water lakes, and broad and sluggish rivers. Save by isolated peaks the Rocky Mountains had not yet been uplifted from the face of the deep, and the great West of to-day was a waste of waters. In the wide forests no bird’s song was ever heard, no Hashing of a wing was ever seen, no serpent trailed its length upon the ground, no wild beast searched. the woods for prey. The spider spun his web in silence from the dew-wet twigs, the locust hopped drowsily from leaf to leaf, the mayfly floated lightly in the heavy air, the slow-paced snail left his damp track on the surfaces of the rocks, and the beetles, lifting the hard coverings from their gauzy wings, flew aimlessly from place to place. In seas and lakes and swampy pools strange fishes swam, up from the salt waters odd reptiles crawled _ to sun themselves upon the sandy shore or make their way through the dense jungles of the swamps, and out where the ocean waves were dashing, _ fieree monsters of the sea darted on their prey, or _ churned the water into foam in savage fights with each other.