In this short essay, I shall examine the post-mining situation on the Witwatersrand, where the underground and the above ground are entwined in intimate flows of geological, biological, economic and socio-political life. A slightly different version of the essay will appear as “Geological Health,” in Questions Concerning Health, edited by H. Sample. New York: GSAPP Books, 2014, forthcoming.
Mine Boy is known as the first modern novel of black South Africa. In it a picture of underground life and of the intimacy between geology and the body emerges.“The men were silent. It was always so. Going into the bowels of the earth forced silence on them. And their hearts pounded. Many had gone in day after day for months. But they did not get used to it. Always there was the furious pounding of the hearts. The tightness in the throat. And the warm feeling in the belly. (Abrahams and Yudelowitz 1963, p.147). The underground, for the miner, was palpable, visceral, felt in the body, and often resulted in sudden, or slow, invisible death. Xuma, the boss boy in Mine Boy, is a rural peasant who comes Johannesburg to find work. A shabeen owner, Leah takes him in and asks him where he will work. “On the mines,” he replies. To which she responds, “The mines are no good, Xuma, later on you cough and then you spit blood and you become weak and die. I have seen it many times. To-day you are young and you are strong, and to-morrow you are thin and ready to die” (Abrahams and Yudelowitz 1963, p.16). Leah is here describing the path through the body taken by silicosis and its resulting pulmonary tuberculosis. They are the primary occupational diseases of gold mining, the consequence of drilling, blasting and grinding at rock faces with a high silica content to produce the ore from which gold is extracted. This releases dust, which, when inhaled over long periods, results in silicosis, often leading to tuberculosis or lung cancer. In a recent book (McCulloch 2012), an account is given of the system of racialized medicine delivered by mining companies in South Africa to treat those diagnosed with these diseases during the apartheid years. White workers were relatively well treated and compensated, whilst black workers, mostly employed as migrant labor on short term contracts, were repatriated once they became ill, exporting what McCullough calls a ‘tide of disease’ to rural areas and neighbouring countries, with enormous on-going social and economic costs.
On the Witwatersrand, the world’s richest goldfields, gold is found, along with uranium, carbon and pyrite in a fractured, dense formation of underground layers, seams and faults. The gold appears as veinlets, specks or grains in the cracks and cavities of layers of carbonaceous conglomerate. This layer can be anything from a centimeter to over a meter thick and slopes at an angle of twenty degrees or more towards the south to depths of at least 5,000 meters. It surfaces in a 3km wide belt from 65kms east of Johannesburg to 145kms west of the city, and then again in the Orange Free State, 320 kilometers to the southwest.
This underground configuration has had profound consequences for the towns and cities that sprung up above to exploit it. Early miners found gold ore close to the surface in long outcrops known as reefs running east to west along the valley floor. These were mined in shallow trenches, but soon exhausted. Accessing the deeper strata of conglomerate required sinking inclined shafts, horizontal tunnels, raises and stopes to extract the sloping gold seam as it fell sharply away. As a consequence of this geometry of shafts and tunnels, the earth’s geological strata were weakened and in constant danger of collapsing.
All that could be constructed over them were lightweight industrial buildings or the tailings of mining operations, colloquially known as mine dumps. Johannesburg and other mining towns were laid out to the north of the initial line of diggings, not only to avoid collapses and sink holes, but also to evade the mine dust blown off the dumps by the prevailing north east or north west winds. The southern industrial extremities of the towns butted up against or were threaded through the metallurgical landscape of mining headgear, battery stamps, reduction works, ore dumps, mine dumps, slimes dams, railways and vacant land.
Early Johannesburg was crisscrossed by a number of small watercourses, the largest of which formed a swampy hollow to the west of the city. Here the poorest inhabitants lived, in what were known as the Kaffir and Coolie Locations. In 1904, pneumonic plague broke out in the Coolie Location. It was cordoned off, evacuated, burned to the ground and its entire population of over 3,000 people relocated to Klipspruit, an area 20 kilometers to the south west of the city (Bremner 2005). This was the first displacement of the city from the north to the south of the gold mines and set the pattern for the subsequent racial reorganization of urban territory. After the proclamation of the Black Urban Areas Act in 1924, the city of Johannesburg was declared incrementally whiter and whiter and more and more black people were forceably removed and relocated to Soweto to the southwest. The mining belt, governed separately from the city  served as a buffer, cutting a great swathe between the two.
Since the 1970’s, large-scale adjustments in the gold mining industry in response to gold’s altered status in the global financial system have resulted in mine closures, mine abandonment or changes of ownership in this central part of the Witwatersrand. Mining operations, buildings, machinery and land, lying close to the city center became valuable resources for a number of other economies: second tier mining companies or artisanal miners have taken over defunct mining property; mining head-gear and plant have been scavenged for their scrap metals; dumps have been reprocessed to remove traces of gold and release their land for real estate speculation; their residue has been pumped hydrologically to gigantic new super dumps further away from the city; and, given the paradox of lying at the center of the urban system but outside of municipal jurisdiction and being too contaminated for development, vacant mining land has been settled by the urban poor.Today there are at least 400,000 of the poorest of people living in informal settlements on this land (Tang and Watkins 2011).
But this land is far from dormant, hospitable or healthy. It is riddled with deep shafts, underground tunnels, mine dumps, waste rock dumps, open cast excavations, quarries, water storage facilities, dams, tailings spillage sites and general unauthorized urban waste. Having been tunneled into, excavated, blasted, pumped and dumped, the earth and its associates are literally buzzing with life. Its topographies, hydrologies and ecologies are adjusting to and recomposing the structural, chemical and radiological after-effects of mining. This has produced less of an environment than what Jane Bennett (2010) calls a ‘vital materiality’- an unstable, entangled, emergent geo-bio-chemico-radiological-social system, and a highly toxic one at that.
The first thing one notices about it is that it leads a highly volatile structural life. It is under-mined by an extensive, invisible, largely unmapped underground network of interconnected tunnels and sloping mining voids propped up by reef pillars, wooden supports and buried infrastructure. Once mining operations cease, this underground void is simply abandoned. It is geotechnically unstable and prone to unpredictable cavings-in and collapses, which crack or fissure the earth, mine dumps, building foundations, floors and walls above it. Its frequently unsealed, unprotected surface openings and ventilation shafts provide passageways in and out of the earth for percolating water, air, animals and people. These include informal settlers and artisanal miners, whose precarious lives often end tragically.
The mine dumps remaining on the land are a stockpile of radio-active compounds and heavy metals.
They contain vast quantities of uranium  and the iron-sulphide pyrite, also known as fools gold (FeS2).Neither of these are in themselves threatening, but when they come into contact with air and water and interact with each other, toxic chemical chain reactions result.
Water scientist, Anthony Turton (2013) has broken these interactions down into a number of sequences, each with a fundamentally different set of cause-effect linkages. They are set in motion by the fall of acid rain on an alkaline, pyrite rich mine dump. This lowers the pH level on the surface and triggers the release of hydrogen, fueling an acidification process. Pyrite (FeS2) oxidizes in the presence of air and water to form an acidic solution of ferrous iron and sulphate. Ferrous iron then oxidises to ferric iron and ferric iron then precipitates as ferric hydroxide, producing further acidification.  The resulting water has a low pH (sometimes as low as 3), a high concentration of dissolved salts (mostly sulphates), high electrical conductivity and mobilises elevated levels of heavy metals, depending on the host geology it has flowed through. The seepage of this water out of surface dumps and into wetlands alters the electrical conductivity of the earth. This makes underground infrastructures using cathode protection particularly vulnerable to corrosion when close to high voltage power lines, caused by electromagnetic forces operating under different parameters. Typical manifestations of acid mine drainage also result in anoxic conditions (the absence of free oxygen), hence the killing off of biological life that can only survive under aerobic conditions. Once the pH of a mine tailing is lowered to 5 in this process, uranium starts to be leached out, at rates that depend on oxic/anoxic conditions.  The oxidised uranium is concentrated in the crust of the dump and, mobilised by wind and rain, is distributed over the landscape and into rivers and wetlands. As it is dissolved by acid mine drainage, its radioactive progeny are mobilized, posing as much of a radiological threat as uranium itself.But uranium and its progeny are not the only radioactive actants here. Radon gas, an odorless, colorless, tasteless, chemically inert gas is released when uranium rich dumps are disturbed or re-mined non-hydrolocally. It is heavier than air and sinks into valleys and depressions in the landscape, decaying via alpha particle emission, with a half-life of 3.8 days. This produces progeny with life spans of between .2 millionths of a second and 26.8 minutes. Despite their short lives, charged progeny can attach to air particles and are a known cause of lung cancer.
When humans and animals are added to this agentic assemblage, their bodies become sinks for the toxic chemistry unfolding around them. For the nearly half million people living amongst this vibrant alchemy, geology is indistinguishable from biology. People inhale airborne radon gas and dust; in some cases, they eat the toxic soil, believing that it relieves stomach pains, or use it as a skin cream; people grow crops on tailings and irrigate them with water packed with radionuclides and chemotoxic metals; these bio-accumulate heavy metals, which, ingested over long periods of time, have carcinogenic effects; the internal organs of animals feeding on grass growing close to tailings seepages are contaminated with uranium and cobalt; children play in the dirt and fall into open shafts; simply by living on or close to mine dumps, people are exposed to elevated levels of direct external gamma radiation. In the Tudor Shaft informal settlement on the West Rand for instance, levels of toxicity are higher than in the Chernobyl exclusion zone (Bega 2011). The slow, violent consequences of these exposures are largely invisible and will unfold over many years, even generations. The adults, children and animals who live in the contaminated zone will be vulnerable to respiratory diseases, cancer, decreased cognition function, skin lesions and health risks from internal irradiation, which include neurological illnesses, diabetes and heart disease (Decomissioning Projects – South Africa 2012; Bega 2011; Dugard et al. 2010).
This slowly evolving ecological disaster affects earth, air, water and flesh. It highlights the intimacy of geo-social relations on the Witwatersrand and the impossibility of untangling them. Instead of this being seen as a threat however, it offers opportunities for activists, architects, artists, health workers, journalists, politicians, scientists and shack dwellers to reincorporate geology into the urban system, urban politics, urban health and the urban imaginary again. This could recalibrate the city and mining wasteland in new ways, forge new alignments between public action and spatial practice, insert design into political debate and gather an unprecedented assembly working towards the possibility of the composition of a common world.
 These are still subject to major class actions for compensation (see e.g. Prinsloo 2009).
 Mining land in South Africa is ‘proclaimed’ once precious metals are discovered. This divests the owner and invests the central state, not with ownership, but with control over the surface of the land and its gold workings. Licensing provisions then entitle it to grant mining title or mineral rights to third parties to mine. It is not subject to municipal legislation, zoning, servicing or policing (see Bremner 2013).
 As I write, the latest incident of the deaths of artisanal miners in a disused mine shaft east of Johannesburg and the arrest of those rescued has unfolded (Reuters 2014).
 Typically, uranium occurs in the earth’s crust in quantities of 2-4 parts per million (grams per tonne). Between 1952 and 1988 during production on the Far West Rand, it was measured at 145 grams per tonne, with averages elsewhere of between 51 and 383 grams per tonne. Witwatersrand mine dumps contain approximately 430,000 tonnes of low grade uranium (GDARD 2011).
 This counters the argument that acid mine water is created underground in abandoned mine shafts and tunnels (as for instance in McCarthy 2010), proposing instead that it is generated on surface mine tailings and seeps into open shafts, slowly rising when pumps are turned off.
 Mine dumps are deposited with a high alkaline content (pH 10.5) because this is the required metallurgical condition for the extraction of gold. Current research suggests that the oxidization of pyrite in these dumps is accelerated by the fall of acid rain, sometimes with pH value of 3. This acidifies the surface of the dump and the chemistry of acid mine drainage kicks in as follows: Pyrite (FeS2) oxidises in the presence of air and water to form an acidic solution of ferrous iron and sulphate. This is chemically described as follows: 4FeS2 (s) + 14O2 (g) + 4H2O = 4Fe2+ (aq) + 8SO42– (aq) + 8H+ (aq), where (s = solid; l = liquid; g = gas; aq = aqueous). This is what happens on the surface of mine dumps when they are exposed to rain water. Ferrous iron (4Fe2+) then oxidises to ferric iron as follows when the acidic water leaves the tailings pile: 4Fe2+ (aq) + O2 (g) + 4H+ (aq) = 4Fe3+ (aq) + 2H2O (l). Ferric iron the precipitates as ferric hydroxide, producing further acid, when the acid water enters a local wetland or river as follows: 4Fe3+ (aq) + 12H2O (l) = 4Fe(OH)3 (s) + 12H+ (aq) (Turton 2013).
 Exposed to the air, uranium oxidises, manifesting mostly as triuranium octoxide (U3O8) and uranium dioxide (UO2). These forms of uranium are soluble in water, contingent upon the pH level of the water and the oxic/anoxic state of the water. Some types of uranium dissolve in water with a high pH level, typically containing carbonates, but the same is true for water with a low pH level, containing sulphates, often in the form of sulphuric acid to which uranium is highly susceptible. What this means is that uranium is dissolved in water with pH levels <5 and >10 (Turton 2013).
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