William Phillips

“ The total ignorance of almost every thing relating to the sciences of geology and mineralogy, and above all of chemistry, in the conductors of mines, and their agents, is not only matter of regret, but it can scarcely be doubted, is also the cause of much loss to the adventurers in mines, to the lords of the soil, and to the buyers of the ore. ”

“ It has sometimes happened that in a large load, and where it is largest, the miner has suddenly arrived at a piece of dead ground in the middle of it, which in depth spreads wider so as to occupy nearly the whole of the vein, leaving on each side only a small connecting string of ore. This has been known to extend many fathoms in length and depth, and from its being narrow above and widening below, it has obtained from the miner the name of a horse. ”

“ The ancient mode of shoding for tin-veins, consisted in tracing certain stones, of which tin formed a proportion considerable enough to excite attention, and found at or a little below the surface, to the vein from which they had been accidentally detached, so as to have passed in a sort of succession down the side of a hill. Another mode of seeking tin veins is by sinking pits through the superincumbent earth down to the solid rock, and driving a trench from one to another, north and south, so as to meet with every vein in the track through which it passed. ”

“ The great copper mine called North Downs, in the working of which no less a sum than £90,000 was lost, may be considered as an instance of the first, and Huel Alfred, from which a greater sum has been gained, is an instance of the second. There is scarcely one symptom on which the miner most relies that has not occasionally deceived him. It may be curious however to add some of the symptoms in favour of which the miner is greatly prejudiced. There is no one more favorable in his estimation than a gossany load. ”

“ Accident often occasions the discovery of veins. That of the mine called Huel Maggot, or Velenoweth in the parish of Phillack, was first seen by workmen employed in digging a trench for the foundation of a garden wall in a valley. It there consisted of a rich gossan, which in the phrase of the miner was very kindly. On driving into the hill, a few fathoms on the ‘course of the load,’ it produced abundance of sulphat of lead in well defined crystals, sometimes accompanied by the sulphuret, and sometimes deposited on the gossan, and, a little deeper, copper ore in considerable quantity. ”

“ The early discovery of iron pyrites and portions of yellow copper ore mingled with a large quantity of blende is considered a favorable omen for copper. Blende, as has already been noted, is by the miner called Black Jack; and ‘Black Jack,’ he says, ‘rides a proud horse,’ a phrase become proverbial, from blende being often found to lie above, in a vein rich in copper beneath. Vast quantities of it were found above the ore in the productive copper mine Huel Towan, as well as in that called North Bennar. The early discovery of lead is also considered a good symptom ”

“ Many tracts of the mining part of Cornwall are however so amply stored with veins in the direction of East and West, that there is little occasion to employ either of the above mentioned modes of discovery. There are comparatively but few mines which are known to have within their boundary only a single vein; in some there are 5, 6, or even 7. As the driving of an adit home to a vein is one of the first and most important tasks of the miner, he sometimes embraces the opportunity of so doing from a neighbouring valley along a cross course, or North and South vein, and for two reasons ”

“ To Captain Thomas Teague, of Redruth, an experienced and very intelligent miner, and who during many years has principally conducted the working of Tin Croft mine, I am indebted for the Section. He informed me that in some part of Dunkin's vein, granite was found on one side of it and schist on the other, and that detached masses of each substance were found both in it and in the South vein; and frequently, that where granite formed the country on each side of the vein, the masses were of schist, and vice versa. ”

“ A vein is termed a caply load when consisting of a hard, compact and unpromising substance, which seems principally to be quartz intermix with minute portions of chlorite, giving a greenish, or brownish green tinge to the mass. Tin is often found in it, copper rarely. But if a branch of copper ore, or a gossan be found to take its course down the vein, it commonly makes a durable copper mine. ”

“ A vein is said to be a pryany load, when the tin or copper ore does not occur in a compact state, but when the stones containing either of them are found mixed loosely with other substances, such as gossan or flucan. Pry in the Cornish language signifies clay.
A vein that abounds in blende is called a black jack load, which is generally unpromising for tin, but is considered a good omen for copper. It is rarely found that blende continues to any considerable depth. ”

“ In few metalliferous veins does the ore prove so continuous, as after it has been taken away to leave a large hollow load. The intermediate spaces between the ore are mostly filled with what the miner terms deads, which consist of quartz, fluor, gossan, iron pyrites and other substances, as well as occasionally portions of the country through which the vein runs; but the walls of the vein are nevertheless generally determinable. The deads are not always a disadvantage to the miner, as they serve to keep apart the country on either side the vein ”

“ But although the mode of discovering veins, by driving an adit along the run of a cross course is at once the cheapest and most expeditious method, it is not always practised, as the foresight of the experienced miner sometimes induces him rather to drive through the solid country than to hazard the chance of being obliged to draw the water of the country all around him, which he is aware the cross vein would prevent from troubling him on one side. ”

“ If experience avails so little, theory cannot be expected to avail any thing; and it may fairly be doubted whether all that science could bestow on the practical miner, would, in this branch of his occupation, be found to be of the slightest advantage. ”

“ Grouan [6] is the common technical term for granite, so that when a vein abounds in that substance, either in masses or blocks, or in a decomposed state, it is called a grouany load, which is rarely found except in a granite country. Grouan is more promising for tin than for copper; though veins containing the latter have often of late been found in the granitic districts of Cornwall, of which the western part of West Huel Virgin, Carharack, and Huel Damsel, all rich copper mines, are instances. ”

“ Almost every mine of any considerable depth or extent, is deserving of the notice of the geologist, because each has its peculiarities:—for when two or more mines are on the same vein or veins, there is frequently but little else that is common to each ”

“ When tin ore is intimately mingled with quartz and chlorite, the vein is termed a scovan load, which is of a dark brown or of a greenish hue, but not very hard, or compact. A load of this description rarely exceeds 12 or 14 inches in width, but it sometimes occurs in a vein the contents of which are not solid, thence by the miners termed a sucked stone. A load so circumstanced is often several feet wide. ”

“ A satisfactory trial of their nature and value can rarely be made, without sinking 30, 40, or even 60 fathoms below the surface, and driving, at various depths, east and west on the “course of the load.”
Symptoms in Veins.
In the whole range of the employments of man, there is not perhaps another in which experience and ingenuity are more often and completely baffled than in mining. Not unfrequently the appearances in a vein considered to be of the most promising kind, lead on the most experienced miners during the lapse of many years only to ultimate and immense loss ”

“ They also hear the rumbling noise of every nodule and fragment of rock, which are continually rolling upon the submarine stratum; which altogether make a kind of thundering roar that would surprise and fearfully engage the attention of the curious stranger. ”

“ It needs not to be insisted upon that much attention ought to be given to free copper from arsenic, which is so very liable to render it brittle. When a pound or two of the ore is given to the sample-trier, as a fair sample of 50 or 100 tons, his report is but too often grounded on the weight of the prill he has obtained from a given quantity of the ore, without reference to the substances with which it may be alloyed, which indeed his skill does not enable him to detect. ”

“ A vein is said to be flucany when either one or both its sides, or walls, are lined with a whitish or bluish clayey substance, or when this substance is interspersed through the vein itself. Flucan in some few instances has abounded so greatly, that it has been difficult to prevent its running in upon the miner in working the mine. This was the case in the early working of the productive copper mine called Huel Alfred, as is noticed in the annexed description of some of its veins. ”

“ And strange as it may seem, it is notwithstanding true, that even the interest of the buyer seldom tempts him to swerve from the hacknied practice of his predecessors, in making purchases to an enormous amount on the reports of those whose skill only extends to the extracting of the heaviest prill, without possessing a knowledge of chemistry sufficient to enable them to discover of what it is compounded. ”

“ These frequent variations in the country through which the miner is under the necessity of passing in the usual course of his occupation in the sinking of shafts and driving of levels and adits, often prove the occasions of great hindrance and loss. There is a narrow channel of a remarkably fine grained substance consisting of compact felspar and chlorite, running in the direction of east and west, a little north-west of Redruth, which is so exceedingly hard as to have obtained the technical name of Ire-stone or Iron-stone. ”

“ While in France, and in Germany, there are national institutions for the education of those intended to conduct the working of mines, in the three important branches of science before alluded to, and which are so intimately connected with their occupation, in this country all is left to accident, and the rich gifts which nature has bestowed upon us, are consequently often neglected, or lavishly thrown away. ”

“ In the counting-houses of the most successful mines the only information ever committed to paper, in regard to the workings of the veins are the expenditure and income, together with a section of the vein from which the profit is reaped, without a single notice in regard to the tract of country through which it passes. ”

“ Although there are veins in various parts of the country which have yielded copper in its pure state in considerable abundance, in masses interspersed through them, and but little intermingled with other substances, or even with the ores of copper, yet the most common state in which this metal is found is that called yellow copper ore. It is more continuous and lasting than any other. There are veins which yield only the grey sulphuret, but this rarely or never continues, being found only in bunches. ”

“ Herland and Drannack mines are situated in a hill that rises suddenly on the west for some distance, but which is afterwards nearly on a level for about half a mile, the highest ground being about the center of that vein termed the Manor Old Load, having a gradual fall to the south of the middle mine. The country is schist, but in some places so hard as to require the blast by gun-powder. ”

“ He walks often in the middle of the night, and in all weathers, two or three or more miles to the mine, undresses, and puts on his underground clothes, and with his tools slung over his shoulder, descends by ladders a depth of 1000 or 1200 feet, assisted by the light of a small candle, and works in the bottom of the mine six or eight hours, amidst the noise of the working of the pumps in drawing the water, with as much alacrity, and with as little sense of danger, as he would feel amidst his ordinary occupations above ground. ”

“ Even now, whatever is not manifestly tin or copper, or is not suspected of yielding those metals, is paid little attention to; and the practical miner sees no value in the inquiry into the run of veins, the nature of the country they traverse, their contents, or uniformity, further than relates in his own estimation to the immediate benefit of his occupation ”

“ In the preceding pages I have aimed at giving a mere general outline of facts, which, considering the imperfect state of geology, seems to be rendering better service to science than could be derived from a feeble attempt to raise upon their basis any theory explanatory of their occurrence. ”

“ An adit is a water course, or rather an underground passage, about 6 feet high and 21/2 wide, and is begun at the bottom of a neighbouring valley and driven up to the vein, for the purpose of draining it of water above their point of contact. In the event also of the mine having a steam engine upon it to raise the water from a still greater depth, it is not raised by the engine to the surface, but delivered into the adit. The general level of the mining-country East and west of Redruth is, according to Dr. ”

“ When its underlie is so much quicker than that of the latter, as to overtake it in going down, the metalliferous vein is generally found to increase in size, not merely in the proportion of the addition of the lesser vein, but very much more, so as to make a great body of ore, called by the miner a gulph of ore at their junction. ”