Our first glimpse of the copper-works was obtained in the 'gloaming'
of a lovely night in August last year, as we rattled over the Landore
viaduct of the South Wales Railway. On each side of us, we could
behold, given out by the chimneys, innumerable flashes of lurid flame,
which rose like meteors into the atmosphere, and scattered around a
brilliant light, that was seen in the distance to blend with the
waters of Swansea Bay. The scene was very beautiful, and singularly
picturesque: we could have wished our enjoyment of it prolonged; but
soon the shrill whistle, the escape-valve, and the lamps of the
station, admonished us that our journey had come to an end.
Our principal object in visiting Swansea, was to obtain some
information concerning the important business of copper-smelting, for
which this port has now become so celebrated. Few of our readers, who
have not enjoyed our opportunities of seeing them, can form any
accurate conception of the vast extent and great economical value and
importance of the Swansea copper-works. Indeed, the copper trade is
far from being popularly known; and the reason is obvious. Iron, which
is very widely distributed in the British islands, is invariably
smelted wherever it occurs. Copper, on the contrary, is only mined in
one or two localities; and it is never manufactured on the spot. This
process is performed almost exclusively at Swansea; and hence the
copper trade of the country is confined to a few individual houses,
and these are in a locality alike remote and unfrequented by the
everyday tourist.
At the period when the first copper-work was established on the banks
of the Tawy, about a century ago, Swansea was comparatively an
insignificant village. It is therefore to this branch of industry the
town and port are chiefly indebted for their remarkable rise and
progress. The population in 1801 was only about 6000; while in 1851,
if we include the copper-smelting district, it had already reached the
number of 40,000. The original cause of Swansea being selected as the
great seat of the copper trade, we may very briefly explain. It was
early discovered that, from the non-existence of coal in the mining
districts of Cornwall and Devonshire, copper, although raised in vast
abundance, could not be profitably smelted there. In fact, it was not
until a considerable time after copper-mining was properly pursued in
Cornwall, that the minerals could be turned to a profitable account.
It became apparent at length, however, both from the large quantity of
coal necessary for the reduction of copper-ores, and the great expense
of the transport, that instead of carrying coal to Cornwall to smelt
the ores--the greater quantity to the less--an opposite course must be
pursued, and the ores carried to the coal districts, and there
smelted.
Now South Wales, poor in copper, is exceedingly rich in coal. Vast
beds of the finest bituminous and anthracite coal exist in rich
profusion in its inexhaustible coal-fields. From its geographical
position and excellent harbour, Swansea was at once selected as the
best port on the Welsh coast in which to establish the copper-works;
and accordingly, the Swansea valley was soon planted with chimneys,
furnaces, roasters, refiners, and, in short, all the necessary and
costly enginery which belongs to the vast and intricate processes of
smelting copper. With such propriety has the selection of a locality
been made, that even now, out of the twenty copper-smelting works of
which the country can boast, seventeen are situated on the navigable
rivers of Swansea and its neighbourhood.
But this was not the only advantage the Cornish miners derived from
this judicious step. The ships employed to transport the ore to South
Wales came back laden with coal to feed their enormous engines; and
thus a system of traffic, mutually advantageous, was originated, and
has continued to exist without interruption down to the present time,
and will continue to exist so long as copper is mined in Cornwall and
smelted at Swansea.[3]
Within the last twenty years, the importation of foreign ores has
become a remarkable feature in the trade and commerce of this place.
Not only is Swansea the seat of the copper trade of this country, but
it may with equal propriety be styled the copper mart of the world.
Large and valuable cargoes of ore are continually arriving at the
Swansea Docks from every country in the world where copper-mining is
pursued. In 1814, there were only four vessels which traded with
foreign ports; in 1849, this number had increased to 771; the greater
proportion of them being directly engaged in the copper trade.
The Cornish ores are sold, as we have seen, in the locality in which
they are produced; but all these foreign ores, from whatever quarter
they may come, are disposed of to the smelters in Swansea by public
ticketing. This ticketing is a curious and characteristic feature of
the trade. The cargoes are usually consigned to a particular class of
brokers, indigenous to Swansea, and known as 'copper-ore agents.' The
ore is by them deposited in large yards, where it is crushed to a
certain fineness, for the purpose of obtaining a proper admixture of
the 'heap.' Notice is then given to the different smelting-houses, who
procure samples of the lot, and assay it. Meetings are held once a
fortnight at the Mackworth Arms Hotel; and on these days the agents
for the ore and those for the smelter take their seats around a table.
A chairman is appointed, who announces the different lots for sale.
Having previously made up their minds what to offer--for there is
nothing like a saleroom competition--the smelters hand up a folded
slip to the chairman, who announces the highest offer and the
purchaser's name. With such expedition does this proceed, that
different cargoes of copper-ore, to the value perhaps of L.50,000,
will often be quietly disposed of in a single hour!
It is very remarkable how closely each offer approximates to the
intrinsic value of the ore. A lot of Chili or Australian ore,
containing a large quantity of metal, may bring L.50 per ton, while at
the same time a poor ore may be sold for a tenth part of the money.
But however variable the offers may be in this respect, they never
vary much in regard to a single lot. Out of the return of the twenty
assayers of the different smelters, probably not a half per cent. of
difference will be found in their estimates of the produce. The
smelters having thus become possessed of the ore, it is transferred to
their own yards, sometimes by means of lighters on the river, but more
frequently by the canal which communicates with Swansea and the
smelting-works.
Leaving the town, and pursuing our way northwards for two miles
towards Neath, we reach the copper-works. The scene is widely
different in open day from that which was presented at night. There is
no beauty now, and little of the picturesque. The first impression,
indeed, the mind is apt to receive, is that of a sense of painful
weariness. Hundreds of chimneys--we speak literally--are vomiting
forth that white, peculiar-looking, and unmistakable vapour called
copper-smoke. Enormous masses of that ugly, black, silicious refuse,
known in the smelting vocabulary as 'slag,' is piled above and around
in such quantity as to change even the physical appearance of the
country.
But this is not all. The noxious gases--which we see and feel around
us--evolved in the reduction of copper, have not played so long on the
surrounding atmosphere without doing their work. Everywhere within
their influence, the perennial vegetation is meagre and stinted. The
hills, particularly to the southeast of the copper-works, are barren
in the extreme. Not one spark of green, not one solitary lichen, can
withstand the ravages of the poison. Time was, we were told by an old
inhabitant, when these hills produced the earliest and finest corn in
the principality; but now they only resemble enormous piles of sandy
gravel, unbroken but by the rugged angles on the face of the rock. In
the year 1822, the inhabitants of Swansea took legal steps to abate
the nuisance. A reward of L.1000 was likewise offered for the
discovery of a successful means of neutralising the effect of the
vapour. The Messrs Vivian of the Hafod Works spent the princely sum of
L.14,000 in experiments, some of which were partially successful, and
are still adopted; but after all, it must be confessed that the fumes
of sulphurous acid, and of numerous other acids alike poisonous in
their character, still taint the atmosphere of the Swansea valley, and
still leave the indelible traces of their blasting properties.
The Hafod Works are the largest in South Wales. Situated on the north
side of the river, they cover a superficial extent of about twenty
acres. The number of furnaces, chimneys, and other brick erections
contained in the works, was far beyond our computation; and we can
speak feelingly of the devious ways and labyrinth of bypaths with
which they are intersected, since, on more than one occasion, we
became bewildered in their mazes.
Here was a group of workmen, half-naked, pouring out of a furnace the
liquid copper at a white heat; there was another group with a red-hot
copper-plate of colossal weight and dimensions, which they crushed
like cheese between the huge rollers of the copper-mill: on one hand,
there was an old furnace, that had done good duty in times past, in
the process of being dismantled; on the other, was one about being
rebuilt; and again there was still another, that had, from long
service, become so impregnated with copper, that it was actually being
built over by a larger one, to be melted in its turn!
We shall avail ourselves of the valuable services of Mr Morgan, the
manager for Messrs Vivian, in our walks round the works, although it
is not our intention to give a technical description of
copper-smelting.[4] Such a course would be alike uninteresting to the
reader and unsatisfactory to ourselves. A consecutive description,
however brief, of what we saw, would, in like manner, carry us far
beyond our limits; and we therefore purposely confine ourselves to
whatever is popularly interesting and instructive in the process.
First in order, then, we proceed to the ore-yard, which presents a
very motley appearance. Under its capacious roof there were tons upon
tons of every variety of ore--native and foreign, blue and red, green
and yellow, and all intermediate colours--indiscriminately piled
around. There was the beautiful green malachite from Australia, the
gray sulphuret from Algiers, the phosphate from Chili, and the
hydrous-carbonate from Spain. There was the glistening yellow
sulphuret from Cuba, the silicate from Brazil, the bright-blue
carbonate from the sunny regions of the south, and the dark-brown
oxide from the colder regions of the north. There was regulus from New
Zealand, and the good old pyrites from the Cornish mines; some
compounds with arsenic, antimony, and numerous other substances; and
last, though in one sense not least, there was a solitary specimen of
ore from Ireland.
These ores were all in the form of a coarse powder. The regulus we
have mentioned is simply the sulphuret deprived, by a preliminary
operation, of its extraneous earthy matters; and this is frequently
effected in the localities where it is produced, such as New Zealand
and Chili, the expense of transport from these places being very
considerable.
'And what is this?' we inquired, looking at a black earthy substance
the workmen at that moment were discharging from a vessel.
'Ah!' said our friend, 'that is a commodity which, I suspect, you know
something about. It is a waste product from certain foundries and
chemical works--from Scotland in this case--and it contains a small
per cent. of copper. We don't care much about it; we seldom have it;
but it is sold at the ticketings regularly. For want of a better name,
we term it _slag_; but it is not slag, properly so called, which you
see all around you. A better denomination is that employed in
designating it in the Journal--namely, _rubbish_.'[5]
'You make no kind of distinction in the ore-yard,' we continued. 'Is
that unnecessary?'
'Well, practically it is. As these heaps lie, you can perceive that a
vertical slice from top to bottom will give us a tolerably even
admixture of the different ores. This is always desirable to a certain
extent, since the ores being of different constitution, the one
materially assists in the reduction of the other. Thus an ore
containing a large proportion of fluor-spar may with great advantage
be employed to flux another containing felspar or quartz, which
substances are almost infusible alone. Indeed, the judicious admixture
of ores constitutes the most important vocation of the smelter; and it
is to this that the copper-houses of Swansea are indebted for one of
their advantages over the proprietors of mines, who, possessing only
one kind of ore--rich, probably, but intractable--can never bring it
into the state of a metal with any satisfactory profit.'
'What is the value of these ores?'
'That varies much. This gray sulphuret contains about 70 per cent. of
copper, and is worth L.35 per ton. This yellow sulphuret, from being
mixed with a large quantity of iron and silicious earth, contains only
about 12 or 14 per cent. Some malachites contain so much as 50 per
cent., and others less pure, 30 to 40 per cent. of copper. But the
greater mass of the ores we melt have a far less produce than this.
That Cornish ore you see there, for example, contains only 4-1/2 per
cent. of metal. The average produce, however, of all the British and
foreign ores smelted at Swansea may be given at about 12 per cent.
Previous to the great increase of foreign importation, it was much
lower.'
We now come to the process of smelting. The theory of reducing
metallic ores, of whatever constitution, is to bring them to the state
of oxides; and then, by the addition of charcoal, and with the aid of
heat, to expel the oxygen in the form of carbonic acid; after which
the pure metal is left. In practice, the reduction of copper-ores is
slightly different. Here the object is to separate, first, the earthy
matters and extraneous metals, by forming them into oxides by
calcination: these are subsequently obtained as waste products in the
form of slag; while the copper is left in combination with sulphur,
which is then dispelled at one operation. According to Mr Vivian,
copper undergoes eight, and sometimes nine, distinct operations in its
progress from the ore to the ingot; and these consist of alternate
calcinations and fusions, extending over a period of from 100 to 120
hours. As, however, some of these are simple repetitions, we may, for
convenience' sake, illustrate the process under its three most
important steps.
1. _Calcination of the Ore._--Having arranged a proper mixture of ores
in the yard, it is weighed out in boxes to the calcining-men. This is
drawn up an inclined plane over the tops of the furnaces, and from
thence emptied through hoppers, 3-1/2 to 4-1/2 tons at a time, into
the large calcining furnace. Here it is roasted for a period ranging
from twelve to twenty-four hours, after which it is drawn into the
ash-pit, where it remains to cool. In this state, the ore is a black,
amorphous substance, and is termed _calcined ore_. The object of this
process is to oxidise the extraneous metals, and also to reduce the
quantity of sulphur, by driving it off in the form of vapour. It is,
therefore, in this and the analogous processes of roasting, that the
sulphurous and arsenous vapours are so profusely given off.
We stood upon one occasion beside a furnace, when the charge was in
the act of being withdrawn; but we took especial care never to do the
like again. The sensation resembled what one might expect to feel on
holding a lighted lucifer-match under each nostril. It is surprising
how the workmen stand it. For the greater part of their lives, these
poor Welshmen exist habitually in an atmosphere so charged with the
above-mentioned abominable gases, that it is difficult to understand
from whence their lungs receive the necessary supply of pure
oxygen.[6] Sulphurous acid, we may add, is the predominant smell in a
copper-work; but arsenic acid, hydrofluoric acid, and even
arseniuretted hydrogen, are not at all unfrequent.
2. _Melting the Calcined Ore._--This is a totally different operation
from the last: in place of roasting, it is one of fusion. The calcined
ore is put into the furnace much in the same manner as before; a
quantity of the slag from a subsequent process is added to assist in
the fusion, and the heat is increased till the whole mass becomes
liquid. The object is to separate the earthy matter, which, from being
specifically lighter, rises to the surface of the liquid mass in the
form of slag, and is drawn off. After two or three charges, the
furnace becomes quite filled, and an aperture is then opened in it,
through which the red-hot liquid flows into an adjoining pit filled
with water. It is by this means granulated, and is now termed 'coarse
metal,' or 'regulus;' and is, in fact, an admixture of the sulphurets
of iron and copper, containing about 30 per cent. of the latter.
But it is to the earthy impurities here given off that we especially
wish to direct attention. This slag, as it is termed, when drawn from
the furnace, is run into oblong sand-moulds, from which, when cold, it
is taken outside to the 'slag-bank,' as it is called--'slag-mountain,'
we prefer saying; and an ugly mountain it is!--where it is broken into
small pieces, examined to see whether it still contains metal, and if
not, is left to accumulate. It consists essentially of silicon,
oxygen, iron; or, to speak more correctly, it is a silicate of the
protoxide of iron. It is, in fact, a true _igneous rock_. Portions of
quartz and silica still remaining unfused, are often contained in the
masses, which give to them, when broken, a true porphyritic
appearance, while, from the great preponderance of the protoxide of
iron, it is invariably black.
So hard, solid, and indurated do these slags, in process of time,
become, that a very tall chimney, the most conspicuous object in the
works, is built on the top of a slag-bank. And this beautiful
commodity is not without its use in the arts. Part of it is
occasionally cast into iron moulds, shaped like old Gothic arches,
only uglier; and the casts are applied in great quantity as
coping-stones to the walls and fences in the regions of the
copper-works. Although not a very tasteful, it is yet a very useful,
and, at the same time, a very characteristic application. We may add
here, that the aggregate produce of the substance of the different
Swansea works may be estimated at about 260,000 tons a year. Our
readers may judge for themselves of the ultimate change this is
calculated to bring about in the Carboniferous System, and of the
learned controversies that are likely to arise among future geologists
with respect to the character and constitution of these carefully
disintegrated rocks!
To return to the smelting process. The last product--the regulus--is
again calcined, with the view of bringing the iron to the state of an
oxide. It is again melted, slagged, and run into pigs. In this last
operation, the whole iron is driven out in the slag, and the
remainder--'white metal,' as it is called--is almost a pure sulphuret
of copper. The sulphur, having all along preserved its combination
with the copper--a fine illustration of the theory of chemical
attraction--must now at length be expelled. This is effected by the
last process of roasting. When in a state of fusion in the furnace,
the charge is exposed to a stream of air, in which case a double
action ensues. Part of the oxygen enters into combination with the
sulphur, producing sulphurous acid, which is expelled in the form of
vapour, and part of it combines with the copper remaining in the
furnace; this is again run out into the form of pigs, and in this
state it is termed 'blistered copper.' To produce the finer kind of
copper, another process has yet to be gone through; but for ordinary
_tough copper_, it is at once transferred to what we may describe as
the last stage, and that is--
3. _Refining._--We quote Mr Vivian:--'The pigs from the roasters are
filled into the furnace through a large door in the side: the heat is
at first moderate, so as to complete the roasting or oxidising
process; after the charge is run down, and there is a good heat on the
furnace, the front door is taken down, and the slags skimmed off. An
assay is then taken out by the refiner with a small ladle, and broken
in the vice; and from the general appearance of the metal in and out
of the furnace, the state of the fire, &c., he judges whether the
toughening process may be proceeded with, and can form some opinion as
to the quantity of _poles_ and charcoal that will be required to
render it malleable, or, as it is termed, to bring it to the _proper
pitch_. The copper in this state is what is termed _dry_: it is
brittle, of a deep-red colour, inclining to purple, an open grain, and
crystalline structure. In the process of toughening, the surface of
the metal in the furnace is first well covered with charcoal; a pole,
commonly of birch, is then held into the liquid metal, which causes
considerable ebullition, owing to the evolution of gaseous matter; and
this operation of _poling_ is continued, until, from the assays which
the refiner from time to time takes, he perceives that the grain,
which gradually becomes finer, is perfectly closed.' After some
further manipulation of a similar kind, the refiner is at length
satisfied of its malleability, and that the copper is now in its
_proper place_, as he terms it. It is then poured out by means of iron
ladles, coated with clay, into ingots or moulds of the different sizes
required by the manufacturer.
'This process of refining or toughening copper, is a delicate
operation, requiring great care and attention on the part of the
refiner to keep the metal in the malleable state.' It is also, beyond
comparison, the most beautiful sight in the copper-works. At one
particular stage of the process, we saw the mass of molten copper in
the furnace--some five or six tons--assume the most beautiful and
resplendent appearance it was possible to imagine. It was like a sea
of 'burnished gold;' and, indeed, were it not for the intense heat,
the red-hot ladles of the workmen, and other little circumstances of
the kind, the stranger would have some difficulty in believing that he
did not look upon a beautifully polished mirror.
We have now come to the end of the smelting process; and have left
ourselves no room to describe the transformation into sheets, bars,
bolts, and boilerplates which the metal undergoes in the next
department of the works. These, however, are a better understood
series of operations, consisting, as they do, of the usual and
ordinary processes of rolling the hot metal between powerful iron
rollers. Nor have we space to allude even to the vastly numerous and
varied applications of the metal; although we may take the opportunity
of briefly adverting to the recently discovered process of smelting
copper by electricity, and of inquiring into the probability of its
ever becoming an economical application.
It will be seen, in the first place, that the present mode of smelting
copper, though simple in theory, appears in practice extremely
complex. For this reason, within the last twenty-five years there
have, we believe, been as many patents taken out to simplify and
hasten the operation. Without exception, these have been proved to be
altogether inapplicable. Let us see how this is explained.
Out of these numerous improvements, we select two that appear
peculiarly attractive. The first is the method of precipitating the
copper, in our second process, from the fused silicates containing it,
by the action of the electric current--the negative pole of the
battery terminating in an iron plate, which replaces the copper in the
liquid mass. The second method is an improvement on this. From some
experiments made at the School of Mines in Paris, it was shewn that
metallic iron alone, without the aid of the battery, was capable of
precipitating copper from the silicates in a state of fusion, just as
it does in saline solutions at ordinary temperatures. But in applying
this last method to practice--for the electricity was obviously
rendered unnecessary by the discovery--it was found that the
expenditure of iron was so great, that it could not be profitably
applied except as a means of assisting the reduction.
'Still,' said Mr Morgan, when commenting on these methods, 'this, in
point of fact, is precisely what we do. We add, as you have seen, a
great proportion of slag to the melting of the calcined ore, which
consists chiefly of the oxide of iron; while at the same time we
derive the additional advantage of employing an excellent flux--an
advantage which metallic iron does not possess. But, irrespective of
these considerations, the plain fact of the matter is, that _it will
not pay_ to smelt copper expeditiously. We don't wish to do so. It is
quite a matter of choice with us those continued operations; and their
great advantage lies in this, that we are enabled to extract every
particle of copper from the ore. By any of these other methods--very
philosophical they are, I admit--we could not accomplish this. The
slags would all contain more or less metal; and when I inform you,
that we can afford to remelt those slags if they contain only a half
per cent. of copper, you will perhaps understand our reasons for still
adhering to our venerable system.'
Thus we discovered that the smelting of copper by electricity, and of
reducing it with metallic iron, would not pay.
Our statistics are short, but they are heavy: about 300,000 tons of
copper-ore are annually smelted at Swansea; 28,000 tons of copper are
annually produced; and 600,000 tons of coal are annually burned. The
value of the ore is about L.2,000,000; of the copper, L.2,600,000; of
the coal, we have no correct means of ascertaining. Of the population
of Swansea, about one-fourth are dependent on the smelting-works; and
of these, about 3500 are directly engaged in the business. The
probable amount of wages paid by the smelters is about L.135,000; and
the current expenditure of the copper-works in the aggregate exceeds
L.500,000 a year.
The last thing we did was to visit the Hafod Schools. These excellent
schools--one for boys, one for girls, and one for infants--were
erected about six years ago, and are still maintained at the expense
of the Messrs Vivian. At the time of our visit, there were 600 of the
rising population of the place doing their utmost to unlearn the Welsh
idiom, and to acquire the art of speaking and writing the English
language with propriety. We regret that we cannot dwell on this the
most gratifying circumstance of our visit. Messrs Vivian & Sons are
unquestionably great copper-smelters, but, in our humble opinion, the
greatest action they ever did, and what must ever commend them to all
good minds, was the establishment of these schools.
To us it was a change, a relief inexpressibly delightful, to emerge
from the Stygian regions of the copper-works, where for the last five
or six days we had wandered like an 'unshriven spirit,' and to find
ourselves in contemplation of the happy faces of the scholars, and to
hear the hopeful, encouraging tones of their intelligent teachers. The
popular song of _Children go, to and fro_, was being sung in the
infant school at the moment we took our leave, and we shall never
forget the impression. It struck upon our senses, to use an
appropriate metaphor, like the crystal stream of the desert--like the
shadow of a great rock in a weary land.