Aplicaciones no clínicas: la lectura de la mente o brain reading

the study area, it is important to be familiar with the types of mineral deposits and veins and how these common minerals are extracted from them (Ford & Rieuwerts, 2000). The most common minerals are found in a network of various types of mineral veins across the Peak District (Ford & Rieuwerts, 2000) and include:

 Galena (lead sulphide, PbS)

 Sphalerite (zinc sulphide, ZnS)

 Fluorite (calcium fluoride, CaF2)  Baryte (barium sulphate, BaSO4)  Calcite (calcium carbonate, CaCO3)

Mineral information: (Hudson Institute of Mineralogy, 2017)

Many of the applications that made galena, or the resulting lead, so desirable in the past are no longer in use, such as the production of paints and pigments, ammunition, water

and plumbing pipes and roofing supplies. Today, although not as widespread, it still has some important uses; it is used for producing leaded fuel, alloys, batteries and as protection against radiation (Ford & Rieuwerts, 2000). The zinc obtained from sphalerite is used for producing alloys and as a zinc coating to corrosive metals, for instance (Montgomery, 2003). Sphalerite, however, can contain some toxic elements such as mercury (Hg) and cadmium (Cd). The other main minerals extracted along with galena and sphalerite were once thought useless; however, these now have several uses and many mine tailings have been reworked to retrieve them (Ford & Rieuwerts, 2000).

Fluorite has many uses in the chemical industry, and other applications include use in anaesthetics, toothpaste, non-stick coatings, and refrigeration and for the fluorination of water supplies. Baryte is mainly used in the oil and chemical industries and in the manufacture of paints, and calcite is utilised mainly in the construction industry (Barnatt & Penny, 2004).

There are four main types of vein where these sought-after minerals are found. There are pipes, flats, scrins and rakes (Barnatt & Penny, 2004). As well as these principal types of vein there are also replacement ore bodies where areas of limestone have irregularly been replaced by mineral deposits, sometimes collapsing, leaving a mixture of limestone rocks and lumps of mineral ore. Areas of gravel ore are also another feature where mineral ores are found, around caves or hollows on the surface of the landscape (Ford & Rieuwerts, 2000). Of the main types of mineral deposits, flats are formed as almost horizontal deposits in between the strata of sedimentary limestone. Pipes form where cavities in the limestone have been mineralised and these can sometimes intrude into the surrounding limestone and replace it, leaving irregular pipe-shaped ore deposits (Barnatt & Penny, 2004).

It is rakes, however, which are the main type of mineral vein, and these provide large deposits of mineral ore. Rakes are vertical fissures that can be several kilometres long (Highley & Cameron, 1995) and often up to fifteen metres wide and 200 metres deep in places (none have been mined to their full depth) (Ford & Rieuwerts, 2000). To mine the

mineral ore from the rakes, miners sank shafts into the rakes at regular intervals and then horizontally along the length of the vein (Ford & Rieuwerts, 2000) and this left waste heaps running along the course of the rake, sometimes for great distances (Barnatt & Penny, 2004). Often these shafts were quite shallow due to problems with the drainage of water from the shaft. Scrins are smaller veins (Hunter & Shaw, 2011), usually no more than half a metre wide and less than one kilometre in length, which can sometimes off-shoot from the major rakes in groups (sometimes called swarms) (Ford & Rieuwerts, 2000). The changes in the landscape owing to the extraction of minerals from these types of mineral vein take three main forms; underground and opencast extraction, which leave behind shafts or open pits, or the removal of surface deposits which leaves behind hillocks and hollows (Barnatt & Penny, 2004), sometimes called bell pits (Ford & Rieuwerts, 2000).

It is the latter type of landscape that is found at study sites Hard Rake (Ford, 2002) and Gang Mine (Ford, 2005). Penny (2005) describes this type of landscape as having hillocks and hollows with varying slope and aspect, primarily composed of the waste minerals disposed of whilst mining the more historically expensive metal ores, with a composition of limestone, calcite, baryte and fluorspar. The study area at Deep Dale also has a hollow, although this is possibly a test pit dug with the aim of following the vein from the top down into the dale itself. Robey (1966) describes the desperate search for galena at Field Grove Mine, directly above the Deep Dale sampling area, in order to capitalise on the mine in the 19th _{century. The landscape at Dirtlow Rake, on the other hand, has undergone vertical}

opencast excavations along it that date back to the early 17th _{century. This has left a large}

open ravine and deep shafts in the landscape (Ford & Rieuwerts, 2000). The present

topography at High Rake mine exists on a very large mineral vein up to twelve metres wide (Rieuwerts, 2011), which has a long history of lead mining dating back to the 16th _century

(Historic England, 2017). This lead mining has left the ruins of several structures associated with the mine that existed here, including ore processing buildings, chimneys and an ore

crushing circle. Large mounds and hillocks also exist here a short distance from the ruins, although these are present due to the more recent re-working of the original waste tips for calcite, baryte and fluorspar (Barnatt, 2011; Historic England, 2017) and also due to extensive archaeological excavations and conservation work which took place between the years 2000 and 2008 (Rieuwerts, 2011). Hay Dale contains a small calcite mine which has been worked from an adit, a near horizontal tunnel, on the side of the dale (AditNow Mining History Society (ANMHS), 2017). Adits are sometimes used as a sough to drain a mine set at a higher elevation (Ford & Rieuwerts, 2000). The entrance to this mine has partly collapsed and there are some remains of old equipment scattered around the survey area. These include parts of a compressor shed, an ore chute (which is just above the dale floor) and a wagon (ANMHS, 2017). According to Ford (2002), this is a 20th _{century mine with little activity having taken}

place. Tansley Dale is a steep sided dale with several mine workings in and around its

margins. Barnatt and Penny (2004, p. 82) describe “a gin circle, a run-in shaft, a coe, a belland yard, a grilled but blocked shaft, a water storage pond, a probable ore-dressing pit and

washing ponds” as being present at Tansley Dale. Sampling here was undertaken around a sough or drainage shaft half way up the dale.

The many different structures and landforms found around the study sites are not just a result of the mining and extraction process. Other processes needed to be undertaken to

produce an ore of sufficient purity, and many of them took place at the same site where ore was extracted (hence the several structures present at some of the study areas) (Barnatt & Penny, 2004). Only approximately 10% of the minerals found in the vein would consist of galena and of that only 86% was likely to be lead (Ford & Rieuwerts, 2000). Once mined, the mineral ores would need to be washed, fragmented and sorted to separate the lead ore from the other gangue minerals with which it was amalgamated. Only after these processes was the final lead ore sent to the smelters (Barnatt & Penny, 2004).

These mineral extraction and other associated processes have had some consequences for the environments in which they took place, and the structures used for these processes can lead to varying levels of contamination in these environments (Kossoff et al., 2016) (Table. 2:1).

Table 2:1. Possible contamination levels around mining structures. Source (Kossoff et al., 2016)

Mining heritage structure

Expected level of contamination

Mining and

processing sites High (if not managed) Underground

workings

Moderate (potentially serious)

Adit High

Spoil heaps High

Tailing dams High

Soughs Low

Remains of smelter chimneys, bellows

etc. Very High

Processing/smelting

structures High

Mining pools or

water bodies High

The next section will discuss the consequences and interactions mining has had on the surrounding environment and further afield.