A system of servitude once existed in Scotland, sanctioned by the practice of two centuries, by virtue of which colliers and their families were fixed to the soil almost as effectually as if they had been bought in the slave-market of New Orleans or born in the hut of a negro on some Virginian plantation. It was not a relic of the social system of the Middle Ages, but was the result of express enactment by the Scottish Parliament.
In the 17th and 18th centuries, coal miners in Scotland, and their families, were bound to the colliery in which they worked and the service of its owner. This bondage was set into law by an Act of Parliament in 1606, which ordained that "no person should fee, hire or conduce and salters, colliers or coal bearers without a written authority from the master whom they had last served". The cruel edict reduced the Scottish collier to the position of a serf or a slave. By that Act, workmen in mines, whether miners, pickmen, winding-men, firemen, or in any other service of the mine, were prohibited from leaving that service either in hope of greater gain or of greater ease, or for any other reason, without the consent of the coal-owner, or of the Sheriff of the County; and any one receiving a runaway into his service and refusing to return him within twenty-four hours was to be fined one hundred pounds Scots. A collier lacking such written authority could be "reclaimed" by his former master "within a year and a day". If the new master did not surrender the collier, he could be fined and the collier who deserted was considered to be a thief and punished accordingly. The Act also gave the coal owners and masters the powers to to apprehend "vagabonds and sturdy beggars" and put them to work in the mines. A further Act of 1641 extended those enslaved to include other workers in the mines and forced the colliers to work six days a week. The Habeas Corpus Act of Scotland, in 1701, which declared that "the imprisonment of persons without expressing the reasons thereof, and delaying to put them to trial is contrary to law"; and that "no person shall hereafter be imprisoned for custody in order to take his trial for any crime or offence without a warrant or writ expressing the particular cause for which he is imprisoned" specifically stated "that this present Act is in no way to be extended to colliers and salters."
In the early centuries of our country's history, while yet the forests were extensive and wood abundant, there was little need for coal. The early coal-workings were of a superficial character, being chiefly of the nature of quarries; indeed, the primary meaning of the word heugh - the name given in past times to a coal-pit - is a steep bank or glen. The labourers on the coal-producing estates, assisted by the members of their families, performed the work when it suited their convenience. Such was the state of the coal-mining population in the sixteenth century, when the country was awakening to a sense of its commercial capabilities. There was a rise of an extensive trade with foreign countries, leading to the wider development of existing coal-works, and the opening up of new fields to meet the demand. The owners of new coal-works, having no trained colliers on their own estates, sought them at established collieries, and induced them by means of gifts and promises of higher wages to leave their employment. This was naturally resented by their masters, who had difficulty in getting sufficient workers for their own pits. The aggrieved coal-owners made application to Parliament to put a stop to the practice. Primarily designed to prevent desertions, the Act authorized a coal-owner to retain his colliers as long as he had work for them. From the fact that many collieries were then in constant operation, and that some have worked continuously to the present day, it is apparent that the colliers attached to works of a permanent character were bound for life, and from generation to generation. And even in the case of collieries where work was not continuous, the worker found that he could not oblige his master to give him a testimonial on leaving, and that he was liable to be recalled as soon as work was resumed. Indeed, it appears to have been the rule for masters to withhold a testimonial, in order that they might the more freely reclaim when need arose. James Gray of Dalmarnock gave up a coal-work and allowed his colliers to go where they pleased, but took the precaution to reclaim them every year in order to preserve his right to them if he should set up his colliery again. It was customary also for the parents of a child to receive a gift from the master at the birth or baptism of the bairn in token of the child's being bound along with the parents.
For the first hundred years after the passing of the Act of 1606, it seems to have been the general belief of both masters and men that if a deserting collier succeeded in evading pursuit, by going over to England, or keeping in hiding elsewhere, for a year and a day, he was then at liberty to work where he chose. This was deemed a grievance by the coal-owners, and they sought to have an Act passed in the year 1700 making their title effectual and not subject to lapse if they, within a year and a day of desertion, cited the fugitive at the market cross of the chief burgh of the shire in which he had his residence. The Act was not passed, for what reason does not clearly appear, but decisions of the Court of Session in 1708 and later had the effect of giving the masters what they desired in this particular. The Lords of Session found that colliers could not be hired without a testimonial from their former master, and that Sir Thomas, having now a going coal-work, might well reclaim them; and, although away several years from him.
The system could not survive the industrial revolution that the country underwent consequent on the development of the use of steam.The process of emancipation began with an Act of Parliament of 1775 which freed the colliers in age-groups - those under 21 and between 35 and 44 were to be freed in 7 years, those between 21 and 34 were to be freed in 10 years and those over 45 were to be freed in 3 years. The liberation of the father freed the family. However, gaining freedom required a formal legal application before a Sheriff and a great many colliers continued to be bound until 1799 when an Act was passed that all colliers in Scotland were "to be free from their servitude".
http://www.scottishmining.co.uk/8.html