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Juan and Mateo are hard rock miners, cutting underground tunnels into the rock to access veins of gold. This is the main mode of mining in Segovia. Explosives are often used to blast the rock to create these tunnels. The gold is of a larger size than the very fine particles found in alluvial mining, but the rock needs to be broken apart to access it. Mercury is generally not used in the mining areas, but in

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This credit is for smaller amounts. While it is appropriate for small dredge owners, I am told it would be insufficient for larger operations such as Esteban’s or Felipe’s.

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specialised gold processing workshops to which the material is bought for extraction.

Juan described hard rock mining as a subsistence activity, a loose term which seemed to refer to the lack of investments and the low income earned. Hard rock mining is, however, a medium term activity, as it can take several years of constructing tunnels to reach the gold bearing veins. This is in contrast to placer mining which has a near continuous period of exploitation.

The miner is proud of his work … I as a miner, when I find, perhaps five grams of gold in a vein, after one or two years working the tunnel, without pay, obtaining food in whatever manner. Then I arrive at the vein. We arrive at the vein, and then it’s a song. We can make money, we leave the tunnel, and go to drink a few beers, and fall in love with a woman, whichever woman. This is the idea of mining, this is how we miners do it. Gambling, drinking and women. Gambling, drinking and women.

This account given by Juan represents both a different material practice of mining and a different mode of approaching mining which is linked to the material conditions of mining. Upon further description, Juan makes it clear that what he takes pride in is not just the mining but the entire process of extraction. He describes mining the gold bearing rocks, grinding them, amalgamating the gold, watching the amalgam being burned, and finally the elusive gold is revealed. It is a process that is practiced and sensorially experienced, not observed, and the satisfaction and pride invested in this are significant. The sensorial experience and practice stand out as a way in which the materiality of mining links to a miner’s mode of approaching mining, an entanglement of miners and materials.

The gold processing workshops13 are where miners bring gold bearing material for extraction, and they are the primary sites of mercury use in hard rock mining. Santiago is the owner of one such workshop in Segovia, located a few blocks from

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the centre of town. The process is divided into two stages. The first stage is whole ore amalgamation in the ball mills, also called cocos, which are round drums containing a metal ball which gives them their name (Figure 7, Figure 8). The gold bearing rock is placed into the rotating cocos, allowing the ball inside to break up the rock exposing the gold. Mercury is also added into the cocos, which traps the gold as it becomes freed from the rock. This process takes about four hours, although it may be repeated if needed, depending on the material being processed. This process is carried out completely by the miner, and neither Santiago nor his employees are involved at all. The miners pour out the resulting mercury into a cloth, squeezing it to release the unamalgamated mercury, then repeatedly washing the amalgam in a bucket until a hardened ball of amalgam is produced (Figure 9). Whenever I observed this process, it was always carried out with bare hands. The miner then takes this amalgam to sell to a gold buyer. The miner does not pay Santiago anything for the extraction service14.

Figure 7: The ball mills in Santiago’s workshop.

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I did not see fees being charged for the extraction service. However, another study in Antioquia reported that many workshops would charge miners a nominal fee of $0.50 to $1.00 USD (Cordy et al., 2011, p. 155).

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Figure 8: A closer view of the ball mills.

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The condition for the miner to be able to use this facility freely is that he leaves all the leftover ground material in the cocos. The mercury process is relatively inefficient, with previous research on these workshops in Colombia showing miners may recover only 30% of the gold (Cordy et al., 2011; Veiga, Angeloci-Santos, Hitch, et al., 2014). Santiago then takes these remaining tailings and proceeds with a cyanide extraction. Santiago keeps 2,000 tonnes of cyanide in two tanks outside of his workshop (Figure 10). This is then pumped into concrete pools inside the workshop where the tailings are left to soak for approximately four to five days (Figure 11), or into pools dug into the tailings themselves outside the workshop (Figure 12). The means of crossing these pools to reach the back entrance of the workshop is by walking over them on a series of rickety wooden planks. The workshop is located within a residential area of the town, and houses are visible in the background of Figure 12.

The street outside the workshop has three restaurants/bars. Mercury that is leftover in the tailings reacts with the cyanide to produce mercury cyanides which are easily converted to methylmercury in the environment. This is a more pernicious form of mercury that is easily taken up by biological systems (Veiga et al., 2006). All the cyanide waste is deposited in the nearby stream, which is completely lifeless. Santiago was reluctant to talk about how the gold is extracted from the cyanide, and I was unable to see this part of the process. However, descriptions are available elsewhere of workshops in Segovia using a zinc and acid based extraction, which releases heavy metals into the environment (Cordy et al., 2011). This process has been estimated to retrieve 80% of the gold in the material being processed at this stage (leftover from the whole ore amalgamation), or roughly 56% of the gold in the material before the first stage of whole ore mercury extraction (García et al., 2015), making this a profitable enterprise for Santiago, but at a significant environmental cost.

This entanglement of miners, workshop owners and materials has produced a system of trust between all parties, and provides a free extraction service to miners who do not have to purchase their own equipment. As the miner is solely

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responsible for the amalgamation using the ball mills, the miner has full confidence that they have their fair share of gold and have not been cheated. There seems to be significant amounts of distrust within the gold industry in Antioquia, which one NGO worker I met attributed to the ongoing violence surrounding gold. The informality of the industry prevents government oversight to ensure fair dealing, even if the government was interested in becoming involved. Bypassing the whole ore amalgamation and simply adding the ground material to cyanide would make it difficult to establish trust, as the miner is no longer in control of the process. It would also be far easier to do this by mixing the ore of different miners into a single batch. However, this would render profit distribution problematic. An additional factor here is the time required. Juan told me that many miners spend much of their time at the mining sites, only coming into town for a few days to visit their families (or party, as the case may be), and do their extractions. As the cyanide extraction takes five days, this option is less attractive than the whole ore amalgamation which takes only four hours. Finally, Juan strongly emphasised how much pride he took in taking the ore from the mountain and processing it to pure gold, and he even joked that there was a religious aspect to this, akin to transubstantiation and a worshipping of gold15. A cyanide extraction would deprive Juan of the pride and pleasure he has embedded in this practice.

While the portion of gold that the processing shop owner receives does seem high, this division of profits has a material basis, interlinked with the material basis of the system of trust. The processing workshop owner could receive 60% of the gold, however, this is the gold that the miner would never be able to access, and so this is not considered a loss16. The rates of gold recovery from using mercury in ASGM are relatively low compared to industrial methods, but high considering that no investments are needed. In this situation, the miner is able to extract as much gold as they possibly could using a whole ore mercury amalgamation method, without making any investment in plant or paying for the extraction. Jairo told me that the

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A number of times I heard vague references to superstitions relating to hard rock mining, but never for placer mining. This could prove an interesting line of future research.

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This also raises the question of the difference between an unfair contract followed scrupulously and a fair one followed unscrupulously, or how injustice is perceived.

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very remote mines carried out their own extraction, as they were too far from the processing shops to transport their material. This required investing in and maintaining ball mills while receiving the same or lower extraction rates as a miner using a processing shop. Mercury’s entanglement here provides miners the ability to perform a moderately efficient extraction with no capital investment. This also avoids the legal risk of extraction equipment being confiscated. As Santiago’s workshop is not a mining operation, it is not regulated by the Secretary of Mines. While his facility is in violation of the relevant environmental codes, this has been enforced only recently.

Some level of investment is needed in hard rock mining for the period of establishing the tunnels, and this credit pathway is also entangled with mercury. Juan said it could take several years excavating a tunnel, without earning, before finding gold. Juan told me he lived off very little money during this time, but the money he did have was mostly obtained from the gold processing shops. Santiago and Juan told me that this could be in the form of an interest charging loan, or the shop owner taking a share of the mine. Both of these arrangements also secured future customers for the workshop, which is completely based around mercury. Once again, mercury has enabled a low investment mode of mining, while the small amount of investment needed is entangled with mercury.

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Figure 10: Cyanide storage tanks.

Figure 11: Cyanide extraction in concrete pools. The planks to the rear are used as a walkway.

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Figure 12: Cyanide pools in the tailings outside. The visible buildings are residential.