The terms upon which the miners held their mines varied. On private lands, when the owner did not work the mines himself by hired labour, he usually bargained for some proportion, an eighth, a tenth, or a thirteenth, of the produce. On the Mendips the lord of the soil received the tenth part as 'lot'; on the royal field of Derbyshire the king had the thirteenth, and at Alston the ninth dish of ore, the dish in the latter case being 'as much ore as a strong man can lift from the ground.'[148] At Alston the king had in addition the fifteenth penny from the other eight dishes, but had to provide at his own expense a man called 'the driver,' who understood how to separate the silver from the lead.[149] This method of paying a proportion of the produce was clearly the fairest to all concerned, for, as the Cumberland miners said in 1278, though they knew that there was ore enough to last to the end of time, no one could tell the yearly value of the mines, as it depended upon the richness of the ore they struck,[150] and in the same way when Robert de Thorp was made warden of the Devon mines in 1308,[151] it was expressly stated that no definite sum was to be demanded of him, because the silver-bearing ore, the refined lead, and the reworked slag all had 'diversetez de bonntez et quantitez de respouns.' In addition to the payment of lot ore, the miners had to give tithes to the Church. In some cases these tithes originated in a definite grant, more often they seem to have been regarded as compensation for the tithes of crops which would otherwise have grown on the ground taken by the mines; but the strangest reason for claiming them was that lead was itself a titheable crop, because it 'grew and renewed in the veins.'[152]
While many small mines were worked by parties of free miners under these conditions, for their own profit, and at their own risk, there must have been from very early times a large number of poor men who worked for the king, the lord of the soil, or capitalist adventurers, receiving wages either by piece or by time. The regulations for the payment of these hired miners in the royal mines of Beer Alston, in Devonshire, drawn up in 1297 are of considerable interest.[153]
'As to the piecework of the miners, those who can find ore in their diggings shall receive for piecework as before, that is to say 5s. for the load,[154] as well of black as of white ore, if the white cannot reasonably be put lower. And those who are engaged in "dead" [i.e. unremunerative] work, and cannot find ore in their diggings, and yet work more, for some dead work is harder than (digging in) the vein, shall be at wages (a lour soutz) until they reach the ore, so that all piecework be undertaken by two or three gangs who divide the profits between themselves, as well to those doing dead work as to the others.'
That the price of 5s. a load was calculated to pay the miners for their preliminary unproductive 'dead' work, may be gathered from the fact that 'tithe ore,' that is to say the ore paid to the Church, was bought back from the rector of Beer at 2s. the load, and a further 9d. was deducted from this sum for washing the ore.[155] At the same time it is clear that where the 'dead' work was exceptionally heavy or the eventual yield small this system of payment would not work; and in 1323 we find that the 'dead work' of clearing, searching, and digging into an old mine in Devon was paid at the rate of 3s. 4d. the fathom, and that two gangs of six men were paid at the daily rate of 7d.-9d., about 1½d. a head, for searching for the vein and for piercing the hard rock to follow up the vein in hope of finding a richer vein.[156]
By the Ordinance of 1297 wages were to be paid every Saturday, though as a matter of fact we find that they were constantly falling into arrears.
'All the ore of each week shall be measured before the Saturday and carried to the boles or other places where it is to be smelted. And knowledge shall be taken each Saturday or Sunday of the issues of each week in all things. And the payments shall be made to the miners and other workmen the same Saturday. And no miner shall remain in a market town under colour of buying food, or in other manner after the ninth hour on Sunday, without leave.'
Besides their wages the miners received such iron, steel, and ropes as they required, free of charge, and had the use of a forge for the repair of their tools.[157] At Beer, in 1297, there were three forges, one for each of the three mines into which the field was divided,[158] and each worked by a man and a boy. In addition to the smiths[159] there would be, as auxiliaries, one or more candlemakers, carpenters, charcoal-burners, and woodcutters. In many mines it was also necessary to employ a number of hands in baling water out of the pits with leathern bodges or buckets; during April 1323 an average of twenty persons were so engaged at Beer Alston, and during one week the number rose to forty-eight.[160] So greatly did the accumulation of water in the pits interfere with work, that in early times the Devon mines were closed down during the winter,[161] and it was not until about 1297 that means were found of dealing with this evil. About that date the plan of draining the pits by means of 'avidods' or adits, that is to say horizontal galleries driven from the bottom of the pits to a level of free drainage on the surface, already in use in the tin mines, was introduced into the lead mines. The ordinances of 1297 arranged for one hundred tinners to work in 'avidods,' and the accounts of the working of these mines for the same year show payments averaging £12, 10s. to 'William Pepercorn and his partners,' and to six other gangs 'for making avidods.'[162] It was probably in the following year that Walter de Langton, Bishop of Chester, reported that the yield of the Beer mine had been doubled by the new method of draining, as they could now work as well in the winter as in the summer.[163]
The ore having been raised was broken up with a hammer, no mechanical stamps being used apparently before the sixteenth century, if then, though there is mention in 1302 of a machine (ingenium) for breaking 'black work' or slag.[164] It was then washed in 'buddles' or troughs, with the aid of coarse sieves, women being frequently employed for this process. The washed ore, separated as far as possible from stone and other impurities, was then carried to the smelting furnace. The commonest type of furnace was the 'bole,' a rough stone structure like a limekiln, with an opening at the top, serving as a chimney, and also for charging the furnace, and one or more vents at the base for the blast. These boles were usually built in exposed and draughty positions, and could only be used when the wind was favourable. At an early date they were supplemented by 'slag-hearths' or furnaces (fornelli) possessing an artificial blast and closely resembling blacksmiths' forges. The bellows of these hearths were usually driven by the feet of men or women, but a water mill was in use in Devon at least as early as 1295,[165] and at Wolsingham, in Durham, in 1426 water power was used when available, the footblast being used during dry seasons.[166] The fuel of the boles was brushwood, and that of the hearths charcoal, with peat and, for the remelting of the lead, sea-coal. In Devon mention is made of a third type of smelting house, the 'hutte,' the nature of which is obscure. The huttes are usually classed with the boles;[167] thus it was noted in 1297 that 'from each load of black ore smelted at the huttes and boles there come 3½ feet of silver-lead, each foot containing 70 lbs. of lead, each pound weighing 25s. sterling. And from a load of black ore smelted by the mill furnace come 3 feet of silver-lead. And from a load of white ore smelted by the furnace or elsewhere come 1½ feet of silver-lead. Moreover a pound of lead made from black ore smelted by the boles and huttes and by their furnaces yields 2 dwt. of silver; a pound of lead from black ore smelted by the mill furnace yields 3 dwt. of silver; and a pound made from white ore 1½ dwt.' In the same way the 'black work' or slag of both boles and huttes were reworked at the furnaces.[168] A possible hint is found in the fact that large quantities of refined lead had to be put into the hutte when it was first lit,'as the huttes cannot burn ore or smelt lead without the addition of sufficient melted lead at the start to roast (coquenda) the ore in the lead so added.'[169] This certainly suggests some sort of cupellation furnaces. Yet another type of furnace was the 'turn-hearth' used in the Mendips; the construction of this, again, is obscure, but it seems to have derived its name from some portion of the hearth being movable and adjustable to changing winds, while it would seem that the ordinary furnace could only be used when the wind blew from a particular quarter.[170] There are references in 1302 to a 'fornellus versatilis' used in the Devon mines, and one entry speaks of making the furnace 'upon the turning machine' (super ingenium versatile).[171]
The bolers and furnacemen, who were paid about 12d. to 16d. a week, their assistants receiving about half those amounts, having cast the lead into pigs and stamped it, handed it over to the wardens of the mine. The next process was the refining of the silver from the lead by cupellation. When an alloy of silver and lead is melted on an open hearth with free access of air, the lead is oxidized and, in the form of litharge, can be removed either by skimming it off or by absorption by the porous body of the hearth, leaving the silver in a more or less pure form. By adding more lead and repeating the process the silver can be further refined. In England it seems to have been usual to remove the litharge by absorption; in the case of the Romano-British refinery at Silchester,[172] the absorbent material used was bone ash, but in the medieval refineries at the Devon mines charred 'tan turves,'[173] or refuse blocks of oak bark from the tanneries, were used, and probably the same material was used in Derbyshire, the southern mines being largely worked by Derbyshire miners. A thick bed of this tan-ash was made with a dished hollow in the middle, in which was placed the fuel and the lead; the hearth was then fired and blast supplied from the side: when the whole was melted the fire was raked aside and the blast turned on to the upper surface of the molten metal, which was thus rapidly oxidized and so refined.
But first, as soon as the mass of silver-lead was in a fluid state, 'before the ash has absorbed any of the lead, the lead is to be stirred and mixed so that it is of equal quality throughout, and a quantity of the lead amounting to about 6s. weight shall be taken out, and this shall be divided into two parts, half being given to the refiner, ticketed with his name, and the date and sealed by the wardens, and the other half shall be assayed by the king's assayer in the presence of the wardens and of the refiner, and the refiner shall answer for the whole of that refining at the rate of the assay, as nearly as is reasonable, having regard to the fact that there is greater waste and loss in the big operation of refining than in the assay. And when the silver has been fully refined it shall be given by the refiners to the wardens for a tally (or receipt) of the weight, so that there shall be neither suspicion nor deceit on either side.... And the lead that remains in the ash after the refining shall be resmelted at a suitable time.'[174] These ordinances of 1297, just quoted, arranged for there being five skilled refiners at the Devon mines, and the account rolls show that they received from 18d. to 2s. a week.