crumbling conglomerate mass; and unless the galleries are substantially
timbered, the chances of their falling in present an instant danger to
the miners. The men who are employed in the work of clearing the ancient
galleries and putting in new levels have had many narrow escapes from
falling earth. The Spanish mining regulations impose a very high rate of
compensation in the case of accidents which occur in the mines; and as a
doctor, whose duty it is to report on all casualties to the Department
of Mines at Madrid, is attached to every working property, mine owners
are exceptionally careful for the safety of their employées. On one
occasion, when the Spanish representative of the present proprietary was
being conducted by the manager through some new workings, a huge piece
of the country rock fell upon his guide. His head was very luckily
protected by one of the hard pot hats which the underground hands always
wear; and although this helmet was badly dented, it probably saved the
wearer’s life. The visitor was naturally much concerned, but the
manager accepted the mishap with smiling philosophy. “You see,” he
remarked, “I am not meant to be an expense to the owners, just yet.”
The labour of fortifying all the drives, as the work advanced, rendered
exploitation both slow and expensive, while not entirely eliminating the
element of danger from the operations. It was at one time intended to
cut the lode by driving an adit into the mountain at a level of 150 feet
below the ancient workings; but as it was discovered that this adit
would have had to be shored up and cemented like an electric railway
tube, the proposal was abandoned as impracticable. Since then, the
difficulty has been successfully overcome by the adoption of another
policy.
[Illustration: THE CHURCH AT HUERCAL.]
The present leaseholders opened their negotiations for the purchase of
the Huercal Mines on the strength of the mammoth dumps which from a
number of assays made by different firms gave results varying from 5·71
per cent. to 10·40 per cent. of copper, 2·19 per cent. of nickel, and
3·13 per cent. of cobalt. It was argued that even if the mines were
worked out, the dumps alone, if scientifically treated with modern
machinery, would return a handsome profit. But very little exploration
work was required to convince the Englishmen that so far from the
property being exhausted of its mineral treasures, the bulk of the
mineral had been little more than pecked at; and a more comprehensive
system of development disclosed the fact that in _El Monte Minado_ they
had acquired a copper-cobalt mine of extraordinary richness. The
consistent and surprising richness of the dumps in carbonates and copper
pyrites made it abundantly clear that if the Romans, with their
primitive methods and appliances, had regarded this ore as unprofitable
for treatment, they must have found still more valuable deposits to
engage their attention. There could be no other excuse for regarding
five per cent. copper ore as débris. For the first time since the Roman
miners left their Bonanza, the old workings were now cleared and the
mystery was solved. These ancient galleries, as will be seen from the
illustrations, were not driven on any systematic plan, but simply
followed the lodes blindly through all their twists and curves. The idea
of going boldly through the mountain and sweeping all before them does
not appear to have been considered practicable by the Romans; and,
doubtless, the danger of excavating in the soft country rock on a large
scale had also been taken into their calculations. As the workings were
freed from the rubbish that choked every drive and level, further traces
of cobalt and nickel were encountered, and copper in its many beautiful
forms became more abundant, and of richer quality. In the Napoleon
gallery the ore was assayed to yield from 17·17 per cent. to 78·69 per
cent. of copper, and at the extreme end of it was found to be in the
face of a three-foot lode, in which native copper was also discovered.
[Illustration: THE CASTLE AND HARBOUR, AGUILAS.]
As I follow Señor José Perez, the mine manager, through the old Napoleon
and Esperanza galleries, it is impossible to resist the contagious
enthusiasm with which he describes and exhibits the property. Certainly
there is excuse on every side for their eulogiums. The copper in the
lodes is very plentiful, while in the hanging-wall of the lodes
important veins of pink and black cobalt are frequently to be found, and
at all points where work had been done abundance of ore has been
exposed. I was shown a large caverture, the roof of which is supported
by a single column of ore, which had been left for that purpose by the
Roman excavators. The miners who were clearing the drives at first took
this circular chamber to be a break in the lode; but it is really a
cavern in the walls, and roof of which nearly every variety of copper
ore is to be seen. The spectacle is strikingly beautiful, and to the
geologist it presents a feature of unusual interest. I have examined
many caverns in mines, but this particular example, which has been
christened “The Cathedral,” far exceeds in natural beauty anything of
the kind that I have ever seen.
[Illustration: HEAPS OF COPPER ORE, HUERCAL.]
A considerable amount of useful development had been accomplished by
clearings and surface cuttings on both sides of the mountain, and these
have been of the greatest importance in the adoption of the latest
scheme for working the mine. In one clearing the outcrop had been
stripped over about 1,100 feet, and by this means the copper and cobalt
lode had been exposed for a distance of 70 feet, and similar work had
been done on the opposite side of the hill. As the result of much
anxious consideration and many discussions it was decided to undertake
the opening up of the mines on a scale which, it is safe to presume, the
Romans never dreamed of, viz., by removing the top of the hill to a
depth of thirty feet, as one scalps an egg. The ancient workings,
situated at a depth of 180 feet from the summit, having been located,
and their dimensions ascertained, the over-burden, which had been found
to be only 30 feet in thickness, will be removed, and from that point
down to 180 feet, where the ancient galleries are situated, is a mass
of copper, cobalt, and nickel ores that will be worked by the
open-cutting process. A trench has been cut from the “Bárris” clearing
connecting with the “Marin” clearing on the other side of the mountain,
and four lines of rails have been constructed to work the ores, which
are loaded up into the trucks and conveyed to the sides of the hill. No
timbering is necessary, shafts and drives are done away with, and all
risks to life are eliminated. The soft nature of the country rock
renders the work, which in quartz would be an impossibility without the
aid of dynamite, a simple pick-and-shovel business, and by this means
the mountain is being gutted at the price of labour and cartage.
THE RIO RIMAL COPPER MINES.
The Rio Rimal Mines, in the province of Gerona, are situated close to
the quaint old-world village of San Lorenzo, which stands, surrounded by
its mediæval fortifications, at the foot of a high mountain. Far above
it an ancient watch-tower still looks out over the wide expanse of plain
and valley. It is broken and weather-beaten, but is otherwise as it was
left by the old Moorish warriors who built it. Within a mile or two, on
the east and west, are the comparatively modern fortified places of
Figueras and Rosas. In the municipality of San Lorenzo, at the beginning
of the last century, was a huge Government Arsenal and Smelting Works,
where the metals won from the neighbouring mountains were cast into
cannon, and made into shot and shell. Among the hills are still to be
seen the remains of busy mining camps where hundreds of men were once
engaged in working the mineral deposits. Before Napoleon’s
all-conquering marshals marched across the frontier the Spanish
Government blew up the arsenal, destroyed the smelting works, and
concealed the entrance to the more important workings. Nothing remains
to-day but a few melancholy ruins to show the extent of the former
operations.
The Government factories were never re-constructed. The proximity to the
border, and the exposed nature of the country, combined with the
experience of the then recent events, rendered the situation too
insecure for the purpose, and the arsenals of San Lorenzo were re-built
on more powerfully-protected spots at Ferrol and Carthagena.
Even the massive stone bridge over the river Muga, which was blown up to
impede the passage of the French troops, has never been rebuilt. The
interesting point about all this is the fact that somewhere, close at
hand in the hills, must exist the mineral deposits which fed the
factories before the Peninsula War. The tunnels and workings have been
very effectually concealed--by no means a difficult matter. A few
barrels of gunpowder would have brought down hundreds of tons of rock
and débris over the mouth of the shafts and galleries, and left no trace
of human handiwork. But that these mines are still there, and waiting
only to be re-discovered, is an indisputable fact.
The operations of the Spanish owners on the Rio Rimal property
commenced, as modern engineering science counselled, near the bottom of
the hill, and they put in their galleries and levels to tap at lower
depth the richest portion of the reserves of copper. But work had only
been in progress for about years when the Carlist war broke out. For
seven years operations had to be suspended, and during the whole of that
period the mine was abandoned. When the owners again turned their
attention to the property, it was to find that many parts of their
galleries had caved in, and the mine had become flooded. After a
considerable interval, the worst parts of the galleries were repaired.
The water was pumped out, the level and inclined shaft were cleared, and
work was resumed. The price of copper in 1874 at Swansea was very low,
and the method of inclined shaft workings being very costly, all hope of
continuing to work the property at a profit was extinguished. For thirty
years nothing was done at the mine. In 1898 an endeavour was made by the
present owners to obtain possession of the mines, but it was not until
January, 1902, that work was resumed on the property.
It was then decided that the most profitable course to be adopted was to
concentrate all labour upon the work of repairing and unwatering the
second level, and of driving a further level some ninety or 100 feet
lower down the mountain side. This work was at once put in hand, and the
north-west gallery was driven a distance of 185 feet on the line of the
lode, cutting entirely through the same for the whole distance. In many
places the lode is mineralised for a width of fifteen inches, the ore
assaying thirty-three per cent. copper. In driving this gallery some
splendid copper was obtained. Work on the level has in the meantime been
progressing steadily, although the workmen experienced great difficulty
on account of the hardness of the rock. At the beginning of this drive a
very hard conglomerate was encountered, which resisted all tools. For a
time the formation defied dynamite, and small progress was made until
the sandstone ground was reached. Thereafter work became easier, and
consequently more rapid.
The Buena Presa property, which adjoins the Rio Rimal Mine on the north,
was subsequently acquired, thus increasing the original area by 141
acres. The Rio Rimal lode traverses the adjoining concession for a
distance of about 2,100 feet. It is a strongly-defined masterly lode,
and has every appearance of producing large quantities of mineral when
developed. Judging from the outcrops, it resembles the Rio Rimal lode
in every respect; and although no systematic work has been done upon it,
the probability is that it will be found to be of equal value.
THE CORUNA COPPER MINES.
The Coruna Copper Company’s property, which covers an area of 2,540
acres--a tract of country more than six times as large as Hyde Park--is
situated in the mining district of Santiago, and is connected with the
railway, which is about eight miles distant, by a first-class road. The
country in which the concession is situated, consists of a series of low
rolling hills, and the character of the ore, so far as it has yet been
explored by the prospecting operations, is very similar to that produced
by the Rio Tinto and Tharsis Mines. It is a low grade copper ore,
carrying on the average twenty-three per cent. of sulphur, and from two
to three per cent. of copper. No attempt was made by the late owners to
determine by a systematic series of borings the extent over which the
mineral actually exists, or the depth and character of the ore; but the
prospecting work already carried out by the English company, and the
natural outcrops found at many points on the concession, place it, in
the estimation of some mining experts, quite beyond doubt that the mass
of mineral is one of the largest known, extending in one direction for
over two miles, apparently without a break. This preliminary work has
clearly proved the whole of the north-west quarter of the concession;
and taking the outcrops into account, one-half of the whole ground is
assumed to contain mineral. Three shafts and nine trenches are being
sunk, and numerous outcrops have also been located on the concession.
The original estimate of the quantity of mineral was 50,000,000 cubic
metres, equal in round figures to 250,000,000 tons. The most recent
assays indicate a mean of three per cent. copper in the ore. The
prospecting work has in every instance proved the accuracy of original
estimates as to the value of the property, as well as the correctness of
the opinion, that a very large output could be obtained with practically
none of the unproductive development work required in most mining
enterprises. It was recommended that mining operations should be chiefly
“open-cut,” and of the simplest character, the exceptionally favourable
conditions under which the ore exists rendering operations an extremely
easy and inexpensive matter. The property is being opened up on these
lines, and it is considered there will be no difficulty in supplying the
concentrating works with 1,000, 2,000, or even 3,000 tons per day, all
obtained from open cutting.
TIN.--THE MINES OF BEARIZ.
Fortunately for the present proprietary of the Beariz Mines, the late
owners possessed considerable technical knowledge; and if the property
was not worked extensively by them, the work was prosecuted on right
lines. They overhauled the Roman shafts and put in new galleries; and at
a time when the standard price of metallic tin was £153 a ton the mine
returned the owners a handsome profit. Some years ago, when the mines
were reopened and actively exploited, a large number of hands were
engaged; and although the ore had to be carted by road to Vigo, large
profits were made. Gradually the price of tin dropped, and the profits
shrank until operations could only be conducted at a loss. Then work was
suspended. Since 1878 the Beariz Mines have remained idle, save for the
persistence of the “Tributors,” who have continued to make a livelihood
by washing alluvials.
The three leases that comprise the Beariz group are entitled the
“Esperanza,” the “Federico,” and the “Elena,” and together they have an
area of 450 English acres of tin-bearing ground. Since the mines were
closed down, the railway has been constructed from the port of Vigo to
within twenty miles of the property, and the roads between Beariz and
the railroad are well made and in excellent repair. Señor S. J. Bárris,
who was requested to inspect the properties and report upon them by the
intending purchasers, spent several weeks at Beariz ascertaining the
dimension of the lodes, estimating the extent and value of the alluvial,
and making assays. He traced four distinct lodes on the “Federico”
property, three on the “Esperanza,” and two on the “Elena,” and his
tests proved that the whole of these nine lodes carried rich oxide of
tin (cassiterite), averaging thirty per cent. of the mineral. “I am well
aware,” he wrote, in communicating the results of his examination, “that
the average will appear to be very high, but I would point out that this
is a very exceptional property; in fact, I have inspected almost all the
known tin properties in Spain, and I can say with confidence that,
taking into consideration the numerous lodes and the very rich alluvial
deposits, these Beariz Tin Mines are one of the richest, if not the
richest, mining properties I have ever seen.”
Worked as a quartz mine, as it was worked by the Ancients, the owners
possess in Beariz an asset of proved value, but the property is rendered
the more valuable by the fact that the lodes represent only one portion
of its assets. For, in addition to the quartz lodes, the greater portion
of the 450 acres is composed of tin-bearing ground, almost every yard of
which will pay to work. On one side of the hill a large number of
boulders are present in the alluvial, which reduces its value; but the
major portion of the area is exceptionally free from unbeatable
material, and consists entirely of tiniferous deposits. Tin is found in
the decomposed granite, which is so soft that it can be worked by pick
and shovels. The upper alluvial is about five feet in thickness; but the
depth of the granitic formation, which is very rich in tin, has not yet
been ascertained. It was for this reason that Señor Alfred Lasala, the
leading mining engineer of Orense, reported that it is almost impossible
to cubicate the quantity of tin ore in these concessions; but he added
in his report that “in every shaft and every trench, cutting, or
outcrop, from the highest point down to the bed of the river Beariz,
which runs at a great depth below the workings, the tin ore is found in
remarkable abundance.” Señor Lasala describes the formation of the
Beariz tin deposit as tiniferous granite, concentrated in great masses
of tin mineral, which is intersected by cross lodes of tiniferous,
quartz veins, or stringers, containing the metal in great quantity. Two
samples of earth, that had been washed to remove the mica, tourmaline,
and other principal elements of crystalline formation that are present
in the ore, assayed 62 per cent. and 81 per cent. of tin respectively;
and Señor Bárris estimates that every ton of tin ore, after being
properly concentrated, will assay from 62 to 65 per cent. black tin.
The upper alluvials contain a smaller percentage of tin than is found in
the lower strata, a fact which is explained by the laws of specific
gravity, and by the attention that has been devoted to the surface
ground in times past. The granitic formation, which is practically
virgin ground, is computed to be hundreds of feet in depth, and there is
enough of it on the Beariz property to employ all the energies of the
company for fifty years to come. The whole of this formation is
traversed by innumerable veins of quartz, containing from 15 to 20 per
cent. of tin, which will add enormously to the value of the output.
THE SPANISH TIN CORPORATION’S MINES.
The Spanish Tin Corporation, which was formed towards the end of 1901,
became the purchasers of 1,361 acres of tin-bearing land in the Arnoya
district of the province of Orense. The Government’s annual publication
of Spanish mining statistics for the year 1900 gives the production of
tin ore for the entire province at 240 tons, and adds, “So far, only one
mine has been producing tin in the province, the ‘Roberto,’ which in
nine month produced 240 tons.” The extent of the concessions, the
richness of the immense tin-bearing alluvial deposits, and the
exceptionally favourable conditions under which they can be worked,
makes the property exceedingly valuable. The whole surface of the
concessions is more or less covered with alluvial soil, with an average
thickness of fully 3¼ feet of tin-bearing ground; and if one-half be
deducted for boulders, surface soil and waste ground, the amount of
block tin is computed at 30,368,365 lbs., and the value at nearly one
million pounds sterling. Practically, it is said, the whole of this vast
quantity of tin can be recovered by simple hydraulic working. In
addition to the alluvial tin-bearing ground there has also to be taken
into consideration the tin contained in the masses of decomposed granite
lodes which traverse the property, and is estimated to contain
60,936,730 lbs. of black tin, of a value of nearly two million pounds.
THE PONTEVEDRA TIN MINES.
The revival of the mining industry has spread even to the province of
Salamanca, where, according to the Government report, not a single mine
had been worked during the year 1900. A reference is made, however, to
visits of mining experts to the districts of Valsalabroso, but nothing
is reported as to the result of their inspections. One result, however,
was the acquisition of three properties known as San Antonio, Adela and
San Pablo, having a total area of 437 acres of tin-bearing ground, on
behalf of English capitalists. Three well-defined lodes have been
discovered, and the leases have been specially pegged out to contain
these lodes for a length of 2,500 metres, or about 2,700 yards. Apart
from these lodes, it is stated that the whole of the ground is
sufficiently rich to allow of the alluvial being profitably worked.
Various tests have been made which endorse this view by giving a return
of nineteen pounds of alluvial tin per cubic yard. The company, which
has been formed in London to work the property, has decided to exploit
the alluvial, while development work is being prosecuted on the lodes.
Special tin-washing machines have been sent to the Pontevedra Mines, and
they are now at work and producing tin. Labour is cheap and plentiful,
and transport facilities are very favourable to economic working, while
another important feature is supplied in the close proximity of a
stream, which gives an abundant supply of water for all mining purposes.
[Illustration: PARAMO.]
THE PARAMO GOLD MINES.
I visited at Paramo, in the province of Léon, an alluvial gold-mining
property, which appeared to possess all the natural advantages for
economical and highly profitable working. This concession consists of an
immense bank of alluvial, over 300 feet in height, and a great plateau,
which has been proved to carry gold wherever tested. The richness of
this plain was evidently fully appreciated in ancient times, and the
remains of gigantic operations can be clearly traced. Water had been
brought in from a great distance by canals; and at the western extremity
of the plain, where it ends suddenly in steep bluffs, two
[Illustration: ALLUVIAL GOLD WASHING, PARAMO.]
great valleys have been sluiced away. The water channels employed for
this purpose are still visible, and are now used as country roads.
Millions of tons of earth must have been washed here, and with
satisfactory results, even with the imperfect appliances then in use, or
otherwise work on such a gigantic scale would never have been carried
out. On the lower ground, very extensive sluicing operations had also
been carried on in ancient times, and a water-race has been brought from
some three miles away. This water-race could be repaired at little cost,
and sluicing be begun here on a large scale with a very small
expenditure compared with what is usually necessary in such operations.
Along the river, on both sides, are level stretches of alluvial, formed
by the eating away of the higher ground by winter floods, and these
deposits carry gold from the grass-roots down.
THE KINGSTON GOLD MINES.