It can certainly be said that superstition is an inherent characteristic of human nature and that, while not every individual may subscribe to a belief in the supernatural, superstitious convictions do feature, and have featured, to some extent, in the ideologies and traditions of many groups and cultures around the world.

It is natural, when one considers the nature of mining, which is both dark and dangerous, that miners, especially those of previous eras, would be prone to superstitious notions concerning their underground working environment.

Indeed, this was most certainly the case during the Middle Ages, as many European miners, in particular, held a firm belief in the existence of underground creatures and spirits. The belief in such underground supernatural beings was, especially before the age of science and enlightenment, most probably developed as a way of accounting for strange mishaps and accidents that sometimes occurred underground.

The belief in subtarreanean mythical creatures is most prevalent in British and Germanic folklore.

In British superstition and folklore, the most common mythical creature to inhabit underground mining areas was the Knocker, also called the Bwca in Welsh. Knockers are particularly associated with Wales and Cornwall, both of which had well-established mining industries during the medieval period.

Knockers were the underground equivalent of the Irish leprechauns, measuring about 2 ft in height, with a grizzled, but not misshapen, appearance. As these creatures inhabited underground mining areas, they were often depicted as wearing miniature versions of standard miner’s garb.

Their name was derived from the supposed knocking sound produced just before a rock fall or the caving-in of a roof.

Some miners believed that the Knockers were actually evil creatures and that the knocking noise was the sound of their hammering at walls and supports to cause the cave-ins. However, others believed that they were essentially well-meaning sprites and that the knocking was their way of warning the miners that a life-threatening collapse was imminent.

Another aspect of Cornish folklore suggests that the Knockers were the helpful spirits of people who had died in previous mining accidents and that their knocking was a warning to the miners of impending danger. To thank them for the warnings, and to avoid future peril, the miners developed a tradition of casting the last bite of their pasties into the mines for the Knockers. (Interestingly, the famous Cornish Pasty was adopted by miners and farm workers in Cornwall during the seventeenth century as a means for providing themselves with an ‘all-in-one’ sustaining meal while they worked.)

The other most notorious mining creature stemming from medieval superstitious beliefs is the Kobold. The Kobold is most prevalent in German folklore and stories of that underground creature were most common during the sixteenth century.

Those creatures were usually invisible, but when they did materialise, they had the appearance of goblins.

Medieval Germanic miners believed the Kobolds to be expert miners and metalworkers who could always be heard drilling, hammering and shoveling in distant areas of underground mines.

As with Cornish and Welsh folklore, opinions about the Kobolds differed, with some miners believing that they were actually indifferent to human miners, as long as they were left alone to mine ore themselves.

However, others believed that they were actually evil creatures, intent on causing mayhem underground. As a result, they were blamed for the accidents, cave-ins and rock slides that often plagued medieval mining operations.

An interesting aspect stemming from the folklore of Kobolds relates to the discovery and naming of the chemical element cobalt.

The story goes that, during the sixteenth century, European miners sometimes encountered what looked to be rich veins of copper or silver but was, in fact, ore rich in the element cobalt.

The first attempts at smelting these ores to produce metals such as copper or nickel failed, yielding powder instead. Also, because the primary ores of cobalt always contain arsenic, smelting the ore oxidised the arsenic content into the highly toxic and volatile arsenic oxide, which harmed the metalworkers and also decreased the reputation of the ore for the miners.

Because the miners and metalworkers had little understanding of this new element, they blamed the Kobolds for fooling the miners into taking worthless and harmful ore.

The miners tried to appease the underground goblins with offerings of gold and silver and by insisting that fellow miners treat them respectfully. However, the Kobolds took no notice of such acts of generosity and continued to fool the miners into exploiting that worthless ore.

Inevitably, that ore began to be referred to as Cobalt, after the mythical creatures from whom they were thought to come.

It was only in 1735 that a Swedish chemist, Georg Brandt, isolated a substance from that particular ore and named it cobalt rex. Further research conducted during that century revealed that this was, in fact, a new element, which was, inevitably, named cobalt.

Such rich mythical folklore is largely confined to medieval Europe and such superstitious beliefs have inevitably died out during the modern era.