Introduction

According to Solidaridad (2020), approximately 100 million artisanal miners exist globally (Abulnaga (2021) agrees on this), and artisanal mining contributes an average of 60% of many countries’ supply of precious minerals, while on the other hand, an average of 70 to 80 percent of small-scale miners are informal, additionally, EPA (n.d.) states that 20% of the gold produced in the world comes from ASM, which releases 400 t of elemental mercury into the atmosphere (Esdaile & Chalker (2018) stated that ASM is the largest source of mercury pollution in the world, releasing 1,000 t/y that includes vaporized mercury), while the OECD (2019) cited by World Bank (2020) asserted that ASM is responsible for the production of 25% of the world’s diamonds, 20% of gold, 80% of sapphires and 18% to 30% of the cobalt.

World Bank (2020) also argues that ASM is the main source of employment for 44.75 million people in 80 countries; citing themselves from 2019, stated that the indirect employment generated by ASM worldwide could be 134 or 269 million people, depending on the multiplier used.

Abulnaga (2021) states that ASM is important for countries such as Morocco, Bolivia, South Africa, and Sudan where it is actively promoted by governments while revealing that in South Africa 30 million people depend indirectly on them mining levels, and in Sudan, around 1 million people depend directly on the activity.

Hilson (2002) argued that despite the potential for benefits that ASM can bring to the rural world and developing countries, it accumulates significant environmental and socio-economic impacts.

According to Olivo (2007), by 2007 there were around 50 thousand artisanal and small-scale miners in Bolívar state, additionally, she cited the Cámara Minera de Venezuela (CMV), which had reported that by the end of 2003, there were produced about 25 t of gold, of which around 15 t were produced by these miners, formally or not, the CMV also stated that for that same date there were between 26 and 30 thousand of these miners in the gold sector; on the other hand, citing the Ministerio de Energía y Minas, it was found that between 2001 and 2004 there was an investment in small scale gold mining of less than 29 million US dollars.

Olivo also stated that the tax evasion of artisanal and small-scale miners was 35% and that, while the Corporación Venezolana de Guayana administered this sub-sector, between 1994 and 1999, it contributed taxes to the treasury for 1,429 million bolivars while the concessionaires contributed 2,205.3 million; she also pointed out that diamond production has traditionally been carried out by this scale of mining.

Sánchez (2021) has stated that currently, due to the reduction in oil production and income from this sector, mining in Bolívar state represents a source of income and employment, while socio-ecological impacts are expected due to the degradation of soils and hydric structures.

GIATOC (2016) as cited in De Souza (2019) revealed that Venezuela along with Peru are considered the largest illegal gold producing countries in the world. De Souza, affirms that the ranking of illegal gold production is led by Venezuela with 90%, followed by Colombia with 80%, Ecuador with 77%, and Bolivia and Peru with around 30%.

It is worth to subscribe what was expressed by Labonne (2014) who argued that ASM exists due to poverty and operates in rural areas that are normally poor, but this mining sub-sector has the potential to finance the desired reduction of rural poverty that costs so many resources to State, in such a way that world governments have acted with inconsistency because with adequate policies ASM can cease to be a problem to become a very important part of the solution. 

Overview. Climate, Vegetation & Soils

Regarding the climate of the study area, it is characterized by presenting a tropical rainy climate, where the total mean annual precipitation is approximately 1,800 mm, registering rainfall greater than 3,000 mm per year, for the entire area. Approximately 64% of the average annual total precipitation falls between May and August. Average annual temperatures vary between 25.7 and 23.4 °C. for altitudes between 100 and 500 m above sea level, and between 23.4 and 20.6 °C for those heights between 100 and 1,000 m above sea level. Concerning the vegetation, there are plant formations adapted to the humidity conditions, temperature, soils, and physiography. According to the Holdridge classification from 1967, the study area belongs to the premontane very humid forest life zone. They represent eventual virgin forests with species whose heights are between 25 and 50 m. Structurally there are 3 defined strata, which are comprised between 0 and 5 m for grasslands, heights between 5 and 12 m with co-dominated species in heliotic competition to reach the upper strata and the upper arboreal stratum with a height greater than 12 m integrated by dominant species forming the typical stratification of tropical forests. With regard to soils, the area is formed by strata with a moderate degree of evolution, which keep close relationships with the lithological substrate and with the different landscapes. The following types of soils are found: Ultisols, Entisols, and Inceptisols. The lithological substrate is closely related to the geology of the study area, which is included in the geological province of Pastora (2,000 to 2,700 million years). The Pastora supergroup group constitutes green rock belts of special interest in this study where the geological Supamo complex is located, whose lithology consists of sodium granite, paragneiss, migmatites, granodiorites, and pegmatite. Finally, recent units are distinguished formed by alluviums containing sands, silts, clays, quartz gravel, and fragments of volcanic rocks. This area is characterized in its entirety by a flat peneplain over metamorphic igneous rocks made up of eroded remains of basic rocks, sandstones from the Roraima group, and the rest of the rocks of a green rock belt. Granite intrusions into the Green Belts, have peripherally originated the location of gold veins of great economic value. The weathering and consequent erosion of their materials have distributed gold alluvium of very high tenor throughout the area and in the major river’s beds.

Background

Quaglia & Barbetta (1991) carried out a study and evaluation of the environmental deterioration caused by gold mining activity in the area of Km 88 (San Isidro) in Bolívar state, and they focused on the exploitation systems used by small-scale miners and the impact that they caused on the environment, specifically vegetation, soil and water, they also evaluated experiences in the recovery of intervened areas and suggested a mining-environmental plan to mitigate damage to nature and achieve harmonization of mining with the environment.

It is evident that the recommendations made by these authors were not implemented or perhaps were implemented only for a time; it is evident, at present, that the magnitude of the damage to the environment in the study area for which they made their recommendations has increased significantly as can be seen in the Google Earth ® images shown in figure 1a, and 1b.

The available scientific literature exhibits dozens of papers that abound in damage diagnoses without proposing feasible solutions, however, a few authors have transcended the eternal diagnosis and have made proposals to contribute to the solution of the problem linked to ASM, above the classic: “stop mining”, some of such papers are exposed below:

Herrero & Rivas (2001) reported the results of an agro-conservation strategy that they carried out in two localities affected by ASM with the purpose, not only, of achieving environmental recovery but also socio-economic-environmental sustainability-oriented toward the post-mining, preparing communities to practice the conservationist agriculture.

La Barbera (2005) carried out a mining-environmental diagnosis in a small-scale mining project in the Hoja de Lata area, Sifontes municipality of Bolívar state, having detected degradation of the terrestrial and aquatic ecosystems due to the discharges of solid waste In suspension, additionally, it made a series of technical proposals to improve mining activities in the sector and reduce impacts on the environment.

Adams, et al. (2007), utilized phospho-gypsum, which is the most important residue from the phosphate fertilizer industry, to recover damaged soils from small-scale and artisanal mining in Venezuela. The results of their research were that phospho-gypsum can immobilize mercury, as kaolin or hematite do. Additionally, the use of phospho-gypsum and sulfate-reducing bacteria together will allow the integral rehabilitation of the devastated areas, but it is necessary to know the bacterial microbiota of soil before the inoculation with any bacteria.

Díaz & Elcoro (2009) determined, between 1992 and 1993, at five ASM areas in Bolívar state, which are the autochthonous species that allow the areas affected by mining to be revegetated, finding that they are common to almost all the mining areas observed, such species are: cyperus odoratus, c. luzulae, Fuirena umbellata, Pityrogramma calomelanos, trema micrantha, and Phytolacca rivinoides, on the other hand, determined that on the surface of the mining tails, the observed species adapt to the poverty of substrate and lack of humidity but as the original soils are normally left towards half or lower, in the tail deposits, observed higher species richness.

González (2013) carried out a characterization of the existing tailing in the IA-12 plot of Bizkaitarra, having established that the recovery of gold was viable, recommending subsequent studies for the use of Ti, Ni and Cr, while recommending that it be coarse material, above 3 mm in diameter, could be used as construction aggregate, for filling, sediment traps, dyke-like structures to control the deposition of tails generated by gold production.

Lozada (2017) stated that ASM could not be eliminated given its socio-economic component, at the same time he recommended that the use of hydraulic monitors and ponds should not be allowed and that it should be eliminated the use of mercury and expressed that artisanal mining and industrial underground mining are which least environmental impacts causes.

Some of the contributions which have been made for getting better ASM from outside Venezuela are:

Chaparro (2000) argued that about miners, the governments of the region, that is, Latin America, should act strictly to safeguard society from people who, within the world of informal mining, act in an uncivilized way resisting, one way or another, for mining to be conducted on a sustainable path, additionally, it stated that policies and instruments should be implemented that would make the exercise of uncontrolled informal mining more difficult, less remunerative and riskier, applying fines, confiscating the produced mineral, and punishing those who buy what they produce.

Hilson (2002a) stated that in Ghana, small-scale mining was an important contributor to national gold production, generating foreign exchange and employment, while mercury pollution and land degradation had been increasing, and established that improvements in the sector would be achieved if the Ghanaian Minerals Commission received help from the government, and academic units, if specific environmental strategies would be designed for the sector, a concerted effort for geological prospecting in search of possible deposits suitable for small-scale mining should be made, a mercury study should be carried out, and a retort program should be implemented.

Hilson (2002b) recommended that governments should begin to promote the reduction of environmental impacts and an increase in the quality of life in the world of miners, which could be possible by formalizing the sector, improving environmental management, and the needs of individual miners.

IIED & WBCSD (2002) proposed that ASM, due to the complexity of its problems, should be oriented to improve its contribution to sustainable development through a coordinated effort that involves all levels of government, communities, and employers, but the proposal contemplated sufficient flexibility to adapt to the various particular conditions, they also recommended that miners should be made aware of the negative impacts they cause and they must be invited to take measures to minimize them, highlights among others proposals that research institutions should focus on finding viable solutions to face the various problems diagnosed in ASM. 

Gunson & Veiga (2004) regarding artisanal mining in China, recommended that instead of continuing with the Central Government practice of trying to close mines, the use of appropriate technologies should be regulated, trained, and promoted, emphasizing approaches integrated and sustainable for artisanal mining communities. These authors made more recommendations, among which it stands out that to reduce mercury consumption, centrifugal concentrators should be incorporated since in China only a few have done so, they also warned that carrying out a total ban on mercury would only lead to its use clandestinely and that the post-mercury cyanidation practice should be eliminated as this achieve greater solubility of mercury in tailing.

Romero et al. (2005) made recommendations for the performance of ASM based on social, governmental, technological, and economic aspects.

To restore areas impacted by ASM, Peixoto, and Perdigão (2006) proposed, prior mineralogical characterization and granulochemical analysis of the materials, the use of a Knelson concentrator and flotation to recover mercury and residual gold, having obtained a recovery of gold of 83.61% and mercury of 41.14%, highlighting that mercury with a concentration of less than 1.50 ppm remains at the bottom of the process, in such a way that this resulting material can return to the environment without generating any risk.

Spiegel & Veigas (2006) stated that despite the importance of ASM (considering the benefits for obtaining income for millions of people in the world), it generates severe negative impacts; revealed that misuse of mercury impacted the environment with 1,000 tons per year despite the existence of technologies that can substitute the use of mercury and make the operation more profitable, additionally, they proposed the competition of multidisciplinary teams that could guarantee satisfactory results with long-term positive effects, they also recommended that the best help could be obtained in initiatives from “bottom-up”, that is, with the participation of governments, communities and miners, rather than options in which solutions are sought from the State or what is also called “top to bottom”.

Aramburú et al. (2010) carried out a study to recover with clean technology, the mercury and gold from tailings generated in amalgamation processes, having determined that by doing a preconcentration with a Falcon concentrator and that the sample has been ground to have a granulometry of 77.89% -200 mesh, followed by cyanidation, it was possible to recover 33.82% of mercury but 66.18% remained in the tailing of this process, while it was possible to recover 97.56% of gold and 2.4% remained in tailing.

Amankwah et al. (2010) conducted direct casting tests in Tarkwa, Bolgatanga, and Bonte, Republic of Ghana, as a technique to replace amalgamation; the tests carried out in the field, using a locally manufactured furnace, allowed an average recovery of 98.3% of gold, while with mercury, 88% was recovered.

Neiva de Souza (2010) has stated that Brazilian regulations for ASM had not been effective, which is why he made recommendations to organize miners and give them adequate access to training, technical assistance, and technology, on the other hand, his work was carried out in the Tapajos region in the Brazilian Amazon where the main impacts caused by ASM are mercury pollution, water sedimentation, and deforestation, highlighting that the uncontrolled use of cyanide has increased risks to health and the environment. The author calculated that annually 6 million tons of sediments are generated that end up in the waterways, to combat this impact, it was implemented to fill the existing pits, produced by abandoned exploitations, with sediments from new exploitations, in other cases, triple barriers made of palm leaves were used, which were efficient to retain sediments.

Neiva de Souza argues that “it is easier to convince miners that reforestation is not only an environmental activity, but a profitable business that involves wood, fruits, seeds, and vegetable oil. Miners are more motivated by economic approaches than by environmental appeals.”, in such a way that it was convinced miners to re-vegetating some refilled pits, and stated that in “Garimpo Canaan, the owner expected that his mahogany plantation would generate future gross income of US$ 3,200/ha/year.” He also assured that “miners adopt environmental programs if they are associated with technical solutions that improve gold recovery or reduce costs, which in any case represents economic gains for them.”

Additionally, Neiva de Souza recommended the intensive cyanidation of concentrates in a ball mill, since the amount of material to be treated with cyanide, compared to the leaching traditionally used by miners, is up to 700 times lower due to the previous gravimetric concentration, also recommended that residual cyanide be treated with bleach or peroxide after it has undergone natural degradation.

Based on factual evidence, got in the municipalities of Tadó y Condoto of Chocó Department in Colombia, Álvarez (2011), established that it was a priority to provide comprehensive technical assistance to stimulate miners in entrepreneurship, associativity, strengthening safety in their operations and occupational health, also asserted that the formalization of ASM would be possible with the coordinated effort of the communities, the State and the institutions.

Zolnikov (2012) stated that the evidence revealed the need for combined efforts to implement and maintain a lasting change, he also asserted that an adequate solution required government support, the knowledge obtained through risk assessment, the recognition of the impact of the buyer through successful Fair Trade gold labeling and education of miners, healthcare workers and locals within the hazardous area of mercury exposure; she argued that by using marketing, gradual changes could be achieved.

Díaz (2013) proposed, for the treatment of acid mine drainage generated in the Cascabel mine in Marmato, Colombia, but that can be extrapolated, according to her, to other extractions in the locality, the use of a lagoon that would receive the drainage generated in the operations and that would allow sedimentation, to the overflow of that lagoon, he has proposed that caustic soda be applied in a concentration of 0.6 ml of 1 molar solution of sodium hydroxide for each liter of acid mine drainage solution and subsequently the use of a filter bed built with anthracite, all of which guarantees, according to the tests carried out, that the pH rises to between 6 and 8, however, although a decrease in the concentrations of heavy metals was achieved, it was not achieved acceptable levels, according to the standards, that is why these waters should not be returned to natural channels in this conditions.

García et al. (2015) reported a successful case of mercury reduction in mining municipalities of Antioquia, Colombia, thanks to an alliance between the United Nations Industrial Development Organization (UNIDO), the government of Antioquia, the National University of Colombia, and the University of British Columbia, with the valuable collaboration of the company Gran Colombia Gold; the result of this experience between 2010 and 2013 led to a 43% reduction in the mercury used in the implementation sites of the cleaner methods that were taught and carried out and also achieved a reduction of mercury losses by 63%.

Adu-Gyamfi et al. (2016) reported that periodic environmental education efforts have been made trying to sensitize artisanal miners from Prestea, Ghana, about the environmental impacts and risks of the activity, but only weak results have been achieved with this measure, in such a way that they recommended that legislation be enacted to regulate the sites where mining and processing could take place.

Luna & Soto (2016) studied 5 mines in Colombia, of which 4 exploited alluviums and one extracted mineral from veins, and determined that due to the use of mercury there was a greater impact on water and air and a lower proportion of impact on the ground; sampling carried out in water showed 1.76 µg/l, sampling in the air up to 3,201.57 ng/m3 and in soils between 1,183.62 µg/kg and 1,949.93 µg/kg. These authors proposed that to avoid the use of mercury, in the case of the alluvial mines they studied, they should use Z-shaped sluice boxes, trommel, jig, and batea to process the final concentrate; in the case of the vein mine, they proposed primary crushing with jaws, secondary crushing with a ball mill, tertiary crushing with a barrel mill, trommel classification, concentration with a vibrating table and/or jig, then with a centrifugal concentrator, stirring cyanidation, after, gold recovery by Merril Crowe and finally smelting.

Pantoja & Pantoja (2016) analyzed the social, political, economic, technological, and environmental conditions of artisanal and small-scale gold mining in Colombia and suggested the structuring of a comprehensive public policy for the sustainable and responsible development of this scale of mining through the implementation of processes for its formalization as well as for the access to less impactful technologies of the environment, and the improvement of the quality of life of the miners and their communities.

Zamora et al. (2017) recommended the sustainable development of small mining in Bolivia in which, among other aspects, they considered technical, environmental, and social aspects, they also recommended that research be carried out in clean technologies for this scale of mining and that the State should obtain international collaboration to support this scale of mining.

Aren da Silva et al. (2018), carried out a review of methods for recovery of areas affected by ASM, having verified that there are methods that are costly and ineffective, they also detected that there are very few long-term evaluative studies, which they considered essential In order to improve in this type of activities, they also considered that the task could be carried out with materials present in the place obtainable at a lower cost, they considered the slope of the slopes and the drainage system very relevant, among others, asserting that The original soil is very important for the environmental recovery phase in such a way that it must be properly disposed of before starting the exploitation, on the other hand, they recommend that research lines should be developed that lead to determining the species that are more efficient in the recovery of each place and case at the lowest costs possible, they emphasize that the follow-up is very important because what recommends the Ecosystem/Landscape Functional Analysis (EFA) be used for such purposes; They emphasized that the planning of recovery activities recommended be carried out before starting operations.

Gomes (2021) carried out work for the use of tailing from small-scale gold mining in the municipality of Peixoto de Azevedo, in Mato Grosso, Brazil to make soil-cement hollow bricks. The experiments were positive based on the Brazilian standard NBR 8491; she also performed the calculation of the thermal capacity, the thermal delay, and the solar factor and compared them with the standards NBR 15575-4 and NBR 15220 for the bio-climatic zone of the study area, having obtained that the results are acceptable according to the first standard but not concerning the second, however, the author proposes that with a clear paint coat or coating the thermal retardation can be increased.

Villachica et al. (n. d.), have stated that in some countries an attempt has been made to ban the use of mercury or high taxes have been applied, resulting in an increase of up to 5 times in the price of mercury, but the reduction in the use of this substance has not been achieved, and much less the pollution that it generates because the miner uses it to survive, in such a way that they suggest an alternative that in their opinion is easy for miners to use and can eliminates the use of mercury, having obtained, in the tests they carried out, gold recoveries 20% higher than the traditional ones, but it should be noted that this proposal is replicable with the same results if the characteristics of the material to be processed are similar to those of the area where the tests were carried out in Puno, Perú, where, among other characteristics, heavy minerals are mostly magnetic or paramagnetic, in such a way that they recommend magnetic separation as a first step, using high intensity magnets that are easily obtained in the markets so that the acquisition price is more feasible for miners and assert that such magnets can be applied manually by any miner; the tests were carried out with neodymium magnets, achieving the elimination of 85% of the weight of the gold material. These authors recommend that, after this stage, the miners should move their material to a place that meets the necessary technical characteristics, where it can be processed with chemicals to obtain the mineral and sell it. They recommend direct leaching of the concentrate, dissolution with aqua regia, dissolution with partner cyanide, dissolution with other reagents, direct smelting, among others, it should be noted that the proposal contemplates recycling and regeneration systems for toxic reagents, and the production of reagents based on non-toxic materials that can be transported and handled without risk.

Km 88 sector. Extraction of gold. 30 years ago

For this work, it is good to establish that the current classification of ASM is different from the one used by Quaglia & Barbetta (1991), that small mining referred to, is the current ASM and not the small industrial mining carried out by Junior companies, the key difference is that in the ASM no geological reserves are known nor has the existence of any ore been determined, on the understanding that ore is a mineral deposit known in location, shape, weight, and quality and that it has been shown that it can be profitably mined. The normal thing is that the ASM undertakes operations like someone who plays the lottery or in a casino, trying to produce in places where the information available is very imprecise.

While small and large industrial mining can only be possible if reserves have been determined, and it has been shown that an ore exists, in such a way that the intervened areas are precisely those required to carry out the project, while in the case of the ASM, areas are usually impacted in which there is no mineral or the one that is found is insufficient to pay the costs incurred.

On the other hand, it is appropriate to point out that the ASM has no real possibilities of undertaking scientific geological explorations such as those required given the enormous investments required and the very high failure rate that accompany this activity, which is the riskiest of the entire mining industry.

Based on the above, the small mining that was studied 30 years ago was made up of those who operated with hydraulic monitors and those who used mechanization, and none of them had proven reserves.

Exploration is the first and most important stage in the discovery of economically profitable mineral deposits. Generally, it consists of geological, geochemical and geophysical prospecting. Unfortunately, this does not actually occur in the studied area. There is a strong lack of a systematic exploration, but rather to an empirical and somewhat improvised procedure.

The exploitation methods used in the study area were mainly characterized for the most part by the use of hydraulic monitors. To remove and transport both the overburden and mineralized material, the hydraulic method involved the use of water pumps, gravel pumps, sluices, pipes, high-pressure hoses, etcetera. Once the mineralized material has been removed, it’s transported through a hydraulic system using gravel pumps and sluices, then processed by concentration methods.

The activity begins with the clearing or deforestation of the preselected area, using blades, chainsaws, and even the hydraulic power of the monitors (powered by water pumps). In this process, the vegetal layer or organic horizon is removed, in addition to the sterile overburden and mineralized horizon. The latter will be processed through a concentration system. While the sterile overburden is sent to sedimentation ponds, old exploitation fronts, or simply to watercourses. Generally, these deposits are defined as colluvial-alluvial deposits. The exploitation or removal of the gold-bearing material is carried out using hydraulic monitors. The pulp made up of water from the hydraulic monitors and the auriferous material removed by them is transported by gravity to the sink or waterhole, from where it is transported by gravel pumps through pipes to the concentration system, starting with the sluice which has an inclination that varies between 12° and 15°, generally 80 cm wide and 7 m long. The material or pulp passes over the sluice carpet, where the gold particles are trapped. The rest of the processed material, also known as “tailing”, is piled up for the filling of the old exploitation fronts, or simply discharged to the water bodies washed and deposited by the river along its course. The concentrate settled in the sluice carpet was collected in a metal box and then with the help of a pan was amalgamated and separated from the black sands and other impurities. Once the amalgam (gold + mercury) was separated, it was burned to obtain metallic gold. Since in this separation process the mercury was released in the form of gas, it was carried out in the laboratory using a retort, where the amalgam was introduced, and it was subjected to heating until reaching the melting temperature so that the separation took place and metallic gold was obtained, and the mercury became vapor, which was conducted by a hose to a container with cool water to condense part of it and recover a good amount of the mercury used. The rest was escaped into the atmosphere. Metallic gold was subjected to a smelting process for refining, introducing it in a stove or furnace. Subsequently, the molten gold was emptied into a mold, obtaining gold bars. (Figure 2). 

Usually, this type of mechanized mining included in the small-scale mining was supported by a pilot plant which consisted of a trommel, “Knelson” concentrators, vibrating tables, mills, amalgamating drums. This equipment allowed making estimates and projections for short and medium-term operations. It was possible to determine in a certain way the amount of mineralized material (Tenor). Consequently, control of the efficiency of the processing equipment and concentration could be achieved, allowing to determine the failures or deficiencies in the system through the periodic sampling of the material that was processed in such a way the concentration process could be optimized. The exploration phase was carried out through pits and trenches planned in advanced phases, which allowed determining the areas to be exploited. Once the samples have been tested in the pilot plant, the exploitation phase was carried out in a mechanized way. The removal and stacking of the material were carried out using tractors. It should be noted that the gold-bearing material, in this case, was of the colluvial type. This material was loaded in dumper trucks by front loaders and transported to the plant. The material was discharged into a hopper where it was classified by a vibrating screen separating the thicknesses that correspond to a diameter greater than 2.5 in and stacking them as tailings. Material less than 2.5” in diameter was taken to a trommel via conveyor belt, where it was de-muddied and re-sorted. In such a way that any material less than 1/4-inch falls through a chute to a jig battery or washing machines where the heavier material goes to the bottom and the light comes out at the top as tails. The retained material in the jigs was conducted through a pipe to “Knelson” concentrators to obtain a concentrate, which consists of gold and black sands for the most part, and mercury if it has been used in the trommel. Gold or amalgam was separated from the black sands using spirals and, in case the volume of concentrate was not very large, it simply uses a pan. The black sands that were obtained in the spiral and the pan were subjected to grinding in a ball mill to then introduce them in an amalgamating drum, so they can be reprocessed again. The rest of the tails that were generated in the different phases of the concentration stage were stacked for later. Getting refined gold was similar to the process described above in the hydraulic monitors mining. (Figure 4).

In the case of vegetation, deforestation is unavoidable, since it is a stage that necessarily must clear the area that has been designated for exploitation. What is questionable in this case, is the irrational way how this stage was carried out. Many times, destroying green areas unnecessarily. This is a consequence of improvisation and lack of implementation of a work methodology where the areas of interest to be exploited are knowledgeably determined. Deforestation is carried out at ground level using machinery and even the hydraulic power of the monitors. The destruction of the natural forest generates issues not only from the point of view of aesthetics and the modification of the landscape but also from the lack of protection to the soil and affectation of wild fauna which finds its natural habitat and refuge in the forest It has been observed, however, in intervened areas spontaneous development of vegetation appearing species that constitute a secondary vegetation succession. Although this can be interpreted as a deterioration of the original vegetation, it represents a favorable point for the restoration and recovery of the vegetation in the affected areas, even more so when the area presents natural conditions and the capacity to do so. (Figures 7 & 8). The authors have the experience of having seen in the Guianese jungle, small areas (from 2 to 5 ha), intervened by artisanal and small-scale miners, which were abandoned and revegetated naturally without the intervention of humans in lapses of about 10 years. 

Regarding the soil, the study area has been affected by the intensive use of land by mining, which through inappropriate methods used, flows and degrades the topsoil and the horizons of the soil profile. The physical and chemical characteristics of the analyzed samples define the virgin soil as frank clayey-sandy, and sandy those that have been intervened in years ago. These soils normally show the mixture of the horizons or strata of the soil profile and in some cases even the inversion in terms of the disposition. Figure 9.

The mixing of the soils and the alteration of their internal structure may, in a certain way, be responsible for the variation of the infiltration pattern; since in the intervened soils, the infiltration rate is much slower than in virgin soils. Figure 10.

Soils are left without any protection whatsoever, being exposed to generalized erosive processes and where the biological activity has very little or no opportunity. The organic matter goes from moderately high in virgin soils to very low in intervened soils, which is a demonstrative factor of soil degradation and its evolutionary condition. Reinforcing the assumption of the lack of nutrient fixation and the low cation exchange capacity surface drainage is also affected since there is the serious problem of the diversion and alteration of the waterways. This problem causes direct effects on the vegetation, flooding forest areas through which the river or stream is forced to pass. Once its bed has been diverted to proceed to the use of the gold ore, both in the floodplain of the river and in its channel. The new channel floods areas that will later draw attention when observing completely dry forest sectors due to the effect of “overwatering”. This prevents normal aeration and oxygenation of the roots of the trees, which die due to water excess. Aquatic fauna was also affected by forcibly changing their natural habitat.

Water is the basis of life and undoubtedly the most important resource. The biological activity of the soil, vegetation, and wild, aquatic, and terrestrial fauna will depend on the quality of the available water. To do this, a sampling pattern was designed following criteria of water quality study; locating stations at upstream control points where there was no mining intervention, close to the mining activity, and close to the mixing zone. The obtained results of the analysis showed important values in terms of solid in all its forms. In addition to the general results of the rest of the parameters determined,  the values of suspended solids detected in the samples from the final stations increased considerably concerning the control stations, which determined the negative effect of the mining activity on the contamination of the studied rivers and streams. As a consequence, values of significant turbidity were also obtained. It should be noted that the total solids were mostly made up of suspended solids, increasing this situation downstream which could be interpreted as the loss of its dissolution capacity, due to saturation problems. However, the contribution of sediments due to the mining activity has been large and continuous. The hydraulic conduction capacity of the rivers depends on the geometric characteristics of the section and the slope of the channel. Then, results were obtained as a function of the number of suspended solids and the average flow rates. Water sample analysis regarding pH and dissolved oxygen, were within the tolerable limits, from pH 6 to 8.5, and dissolved oxygen not less than four milligrams per liter, as established in the partial regulation of the Organic Law of Environment at that time. In the study area, it was detected water table associated with gravel and sands from the studied virgin soil profiles. These phreatic layers were found at a depth of approximately 3.6 m, and they were interrupted by mining activity at the time of removal of the material. It was also associated with gold ore. Another problem encountered as part of the environmental deterioration was the terrible conditions in which not only the miners live, but also their families and other people who were located in the area for one reason or another. They stay in tents and barracks, almost always near the work area. Where there are generally stagnant waters and therefore the risk of contracting diseases such as malaria, transmitted by insects found in a favorable environment for its reproduction. There is, of course, the danger of mercury poisoning, since the use made of this element is not controlled; despite having restrictions and prohibitions regarding its use. The miner runs the greatest risk in the recovery stage of the mineral, due to the inhalation of harmful mercury vapors. Culture has been decisive in the search for the causes of this issue, so in addition to a socio-economic and health conflict, it also represents an education problem that is essential to solve.

What is currently happening in the extraction of gold in the km 88 sector

At present, ASM in gold and diamonds is taking place in the materialization of what former President Hugo Chávez presented to the country as the Orinoco Arc in 2012 and then, in the Council of Ministers, approved the Strategic Plan for the Joint Development of the Oil Belt and the Orinoco Mining Arc, all this according to the Ministry of the Popular Power of Ecological Mining Development (n. d.), all that remained there, until his successor’s government, through decree 2,248, has denominated as the National Strategic Development Zone “Arco Minero del Orinoco” (AMO, acronym in Spanish) in Venezuelan Guiana, which, as is known, belongs to the Venezuelan Orinoquia, so mining in such territories should be carried out with order, science and technique, which in practice is very far from the “ought to be”, on the other hand, all kinds of social calamities have been unleashed, all in according to various authors, among which are cited:

De Souza (2019) revealed that in recent years there has been an exponential growth of violence, of insurgent groups, of miners from neighboring countries, of indigenous people with high levels of mercury in their blood; she also claimed that the region’s water was highly contaminated with mercury and other heavy minerals. De Souza argued that Las Claritas and Km 88 are controlled by insurgent groups that try to control more than 63,000 illegal mines that have more than 3,000 illegal miners from Colombia and Brazil.

Mora & Rodríguez (2019) as cited in Aguilar & El Fakih (2021) pointed out as problems generated by the Orinoco Mining Arc the forced displacement of indigenous people, deterioration in the health of these citizens, social neglect by the State, increase in military-police interventionism, and exacerbation of violence in communities.

Lozada et al. (2020) argued that the mining business is not one of the traditional activities of indigenous peoples, despite the fact that some of their leaders now justify it and carry it out as a result of the fact that these peoples were already in the process of transculturation, which it facilitated the exercise of an activity that was not normal for them since their ancestors carried out artisanal mining since pre-Columbian times. Based on exposed by Milano (2008), Grillet et al., (2009), Lozada (2017), and Vitti (2018), they listed the following impacts caused by indigenous commercial mining in the 43 sites they studied, namely: “: the destruction of ecosystems and rivers topography, habitat fragmentation, death and displacement of fauna, pollution of water and fish by sediment and mercury, mercury-borne diseases, favorable habitats for malaria-carrying mosquitoes, increased incidence of malaria, the emergence of criminal armed groups, increased incidence of prostitution and violent deaths, as well as misuse of drug and liquor”

Machado-Allison & Chernoff (2020) stated that with the mining arc it has not been possible to change the unproductivity and inefficiency in mining, additionally, they revealed the existence of illegal acts and abuses of power, of corruption, also, they pointed out that it was not applying the constitutional principle of control and approval of contracts by the Legislative Power and that in all this the most affected are the environment and the indigenous and creole peoples who traditionally live in the areas.

Moya et al. (2021) stated:

“... there is the case of men who moved to the south of Bolívar state with a job offer that included a salary, lodging, and food, and ended up working in a mine for more than 12 hours a day, without any kind of protection, having as an obligation the delivery of up to half of their profits to the so-called “unions” (Venezuelan armed groups) and to the Colombian armed groups that control the sector and being victims of constant threats in the event of any error, or breach of the rules by these imposed, with actions such as the amputation of some of their limbs and even death. In the case of women, their involvement with prostitution is more frequent in mining areas, and if they have any disease, they are, or expelled from the population, or punished with physical abuse. These activities not only occur as a result of misleading offers but also the situation of people who, attracted by the vision of mining as a mechanism to obtain quick money, undertake their journey to these areas, given the scarcity of opportunities that exist in the country and end up trapped in the dynamics of the mining sector.

Minors are also victims of mining, both directly and indirectly. In 2019, Cecodap reported that 45% of mine workers were children and adolescents. Directly, since their kinship with miners leads them to inhabit the mines, and their size makes it easier for them to enter the narrow-improvised tunnels for the extraction of gold. And indirectly, because their parents go to the mines and leave them unprotected, with relatives or acquaintances, and end up wandering in the streets as in the case of the children in the Plaza de El Callao, where a group lives whose ages vary between 8 and 12 years old.” 

We could also cite abundant information on social networks, generated by politicians and environmentalists, which have a lot of visual impacts (works of art from photography and documentaries), but the vast majority lack field studies with samplings, results, and analysis. So far the visual display of what would be happening is similar to what happened before the “State atrocity” which is colloquially known as “Mining Arc”, it is also similar to other devastation carried out by artisanal and small-scale miners in other countries. Basically, what is observed is not mining but a rather irrational plundering of resources of nature and of humanity itself, with which no one, with a minimum environmental awareness, could agree, but the real solution does not go through the extinction of this production sub-sector but through its complete transformation and support to realize its evolution, on the other hand, its extinction has never been achieved in the countries where it has been tried, since the problem is much more complex than what can be seen by those who only approach from one, two or three aspects of the problem, or from a non-scientific approach and, yes, very fanatic. Fanaticism will never offer sustainable solutions over time.

Proposal

From the technical point of view, the recommendations made by Quaglia & Barbetta (1991), as well as what is indicated in Sernageomin (ND), Sernageomin (2003a), Sernageomin (2003b), UPME (2007), Lujan (2008), UNEP (2008), Telmer & Stapper (2012), Eppers (2014a), Eppers (2014b), Meller & Meller (2021) and all others that have been mentioned so far are perfectly applicable and very positive for the reduction of negative impacts of the ASM, however, it is necessary to understand that these scales of mining should be helped to disappear through evolution, becoming clear that the proposal that arises below, is not aimed at achieving the totality of the extinction of ASM, since it is really impossible given that not every miner feels the need to evolve in what he does and that is perfectly natural in humanity.

It is necessary to keep in mind at all times that what prevents the evolution of miners, who wish to evolve, is the absence of knowledge about reserves that may exist, in such a way that it is necessary to promote from the State, that small-scale miners could perform geological exploration, but, normally, handmade and small-scale miners are found in survival situations, either because they enter the sub-sector due to prolonged unemployment or because culturally, despite receiving fortunes occasionally, they do not have the minimum knowledge of administration to preserve the riches that obtain and in many cases do not even feel the need to prepare for the most everyday situations in the exercise of these mining scales such as non-obtaining mineral or obtaining as little that production costs cannot be defrayed.

Based on the above, it is having that even though some miners realize that it is preferable to reduce the volatility produced by dispersed deposits and the absence of reserves, they do not have the money and other necessary resources. Some people have always proposed that the State create financing programs for small-scale miners to carry out exploration and others have proposed that the State carry out exploration for this scale of mining; in this proposal, it is not contemplated that the State carry out extremely high-risk expenses such as these since it is irrational to do so.

In small-scale mining in Venezuelan Guiana, there have been mining cooperatives and civil mining associations, with concessions or mining contracts granted by the State, that is, with real rights in the first case and precarious rights in the second case, which is important to be able to evolve, if it is the first case; additionally, in some of them there were people with vision and spirit to evolve, miners who realized that they could do better if they took steps to reduce the enormous volatility that characterizes this subsector, but in all the attempts they made to try to evolve, they encountered obstacles in the Venezuelan legal framework, in the mentality of officials and inside public opinion. Basically, perhaps unintentionally, everything is designed so that they are always small, vulnerable, dependent on the state while also being a heavy burden on the state and society, prey to leaders with secondary intentions prioritizing themselves and not for the miners they represent, and much less the communities.

However, as part of the nature of some human beings, there are always those who do not conform to the situation in which they find themselves and want to produce changes, in such a way that at the end of the 90s, in some organizations of small miners, part of the income was used to carry out some exploration, but they could not sustain the initiative, in such a way that the small miners began to think that the State should give them money to explore as well as carry out a technological reconversion, that would allow them to replace hydraulic monitors and the use of mercury, of course, this option is unfeasible if those who govern are responsible and knowledgeable about the mining business, so the best option is to modify the legal framework of both mining and cooperatives, since it is necessary to allow that miners can partner with each other and/or with national or foreign businessmen, to undertake formal geological explorations based on the legal framework that is in force, in such a way that by achieving quantification of reserves, they can abandon the status of small-scale miners to higher scales. Logically, it is contemplated in the legislation that small-scale miners obtain precarious rights, as it should be since they do not have proven reserves, but that obtain real rights such as exploration concessions could be easy for them, if through association with companies, nationals, or foreigners, and/or with their resources, can justify obtaining a concession of this type.

The proposals made here for gold and diamonds ASM in Venezuelan Guiana have been conceived without considering the diverse crime problems existing today and which have been briefly described in previous paragraphs, drug trafficking, human trafficking, slavery, the mafias with their diverse and changing names, the presence of illegal Creole “military” forces and foreign guerrillas, are problems for which the authors of this proposal do not have any expertise because the experience is in geosciences and not in the field of detective investigation or intelligence services. It is necessary, to implement what is recommended here, that order be previously restored in Venezuelan Guiana.

Considering that there is a lot of misinformation regarding possible deposits suitable for artisanal and small-scale mining, but taking into account that there is a socio-economic pressure for those who carry out these activities to try to obtain income for their survival and that of their families, in a ruined country in which the salary does not sufficiently reward the work done to obtain it, it is necessary to carry out a transitional period that has been conceived as follows:

1. Artisanal and small-scale miners should be allowed to work only in areas already intervened, not in virgin areas, nor inside watercourses, nor between the banks of rivers and the line parallel to them 300 meters away, all this based on article 54 of the current water law. The exception about bodies of water could be considered only to avoid aggradation, dissolve aggradation or prevent damage to navigation, or any other reason accepted by the national institution with competence in the environment.

2. The organization and association of miners should be promoted using any of the forms of association (civil or commercial) in force in Venezuelan legislation.

3. Each artisanal miner could be assigned plots of 2,500 m2, while each formal organization of artisanal miners, as an incentive to promote the organization of these miners, could be assigned 5,000 m2 for each associate member. Individual small-scale miners could be allocated a plot of up to 1 ha, while small-scale miners’ organizations could be awarded plots of up to 2 ha for each member of the requesting organization.

4. In each ASM´s area, the existence of natural or legal persons, authorized by the institution with competence in mining, who provide services of heavy machinery, equipment, concentration plants, and mineral trading should be promoted.

5. Underground work should not be carried out without the approval of mining engineers whose professional practice has been approved by the institution with competence in mining. The loss of human life due to poorly executed mining is not acceptable in any way.

6. It should be promoted that the operations of both artisanal and small-scale miners are coordinated in each area so that all of them contribute to the materialization of the environmental recovery of the area.

7. The use of hydraulic monitors can be allowed in areas environmentally impacted by previous exploitations and in tailing deposits, as long as the operations with this equipment do not generate more damage to the existing watercourses or the surrounding virgin environment.

8. All the waters and pulps from the exploitation and the concentration must be directed to sedimentation and clarification lagoons, of which there would be as many as required so as not to return to the rivers, lakes or streams, waters of lower quality than that which was obtained from these bodies of water, preferably, mining operations should be supplied mainly from the waters present in the lagoons. To have enough lagoons, mining excavations that have already been “totally” exploited can be used.

It is recommended that national or foreign universities that train professionals in mining engineering, environmental engineering or chemicals, both undergraduate and postgraduate, as well as research centers or equivalent, private or public, national or foreign, carry out perennially research and provide support, in each zone of artisanal and small-scale miners, about the best products to use to make the sedimentation process, clarification and improvement of the quality of the waters coming from the operations and concentration plants more efficient, in such a way that only the waters of equal or better condition to the one they originally had, are those that are returned to nature and so that each aspect related to artisanal and small-scale mining is better and better in favor of obtaining real improvement and continuous quality of life for miners.

9. Neither artisanal nor small-scale miners would be allowed to use chemical substances to capture gold, they will only be able to make hydro-gravimetric concentrations and take their concentrates to authorized places to subject them to adequate processes for the recovery of the mineral. Miners or artisanal or small-scale mining organizations that have adequate facilities in accordance with the national institution with competence in the environment and that have mining engineers or chemical professionals as responsible for them are excepted. It is necessary to modify decree 2.412 of 2016.

10. It will be necessary to design a practical plan to re-educate artisanal and small-scale miners about the use of mercury and the wrong way they have normally been operating; they must be shown the falsehood of the various myths they have regarding mercury and the mistakes they always make in their production operations; miners should be convinced of superior recovery with the alternative methods that they must be proposed to have less impactful mining compared to what they normally use. It is necessary to reiterate the practical nature that the implementation of this recommendation should have, as well as the need to convince rather than impose.

During the years that the transition period would last, new areas would be identified in which formal jobs of artisanal and small-scale miners could be organized, which could be areas that, after explorations carried out by industrial mining, do not interest them and they have returned to the nation or explored areas that the companies have left out of the project and that could be exploited by artisanal and small-scale miners without affecting the operations of the company and prior release of responsibilities to the company for the environmental impacts that could be generated by ASM. In any case, virgin areas where the existence of minerals of interest to ASM is unknown should not be allowed to be intervened. On the other hand, in areas that industrial-scale mining companies could allow to be exploited by ASM, only precarious rights may be granted as they would be areas in active concessions. Based on what is stated here, the following is recommended:

The exploitation of the parcels that are granted for ASM must be exploited within the framework of a strategy that allows the environmental recovery of the entire surface that has been planned to be affected, in such a way that each of the natural or legal persons to those who are awarded the plots, they will contribute to such objectives both, financially, and by following the technical guidelines that have been approved by the institution with competence in mining.

The first recommended stage consists of carrying out a topographic survey of the area to be intervened, it should also be spatially inventoried, it may be with the help of a geographic information system, the various species that are found in the area where the mining will be carried out is It is advisable to collect seeds and seedlings of the native vegetation as well as a characterization of the soils, however, in this matter, the appropriate procedure must be that established by professional specialists in environmental recovery as long as it has the endorsement of the national institution with competence in the environment.

The next stage would contemplate deforestation if there are forests; it is recommended that it be legally allowed to make use of the existing useful wood for the necessary infrastructures in the mine, if it were in the interest of the miners, if there were species of interest to the markets and they are not going to be used in the project, they should be commercialized, and the money from the sale, reserved to be used in the environmental recovery plan, the rest of the forest material, which could not be commercialized or used in the project, must be properly preserved at the judgment of environmental professionals to be used in the work of environmental recovery.

All the topsoil and each underlying horizon must be removed with heavy machinery, mining rakes, or manually and stacked separately, in places and conditions previously established to preserve them without deterioration until it is necessary to use them for environmental recovery. The use of hydraulic monitors could be allowed in the mineralized layer as long as it is not soil. When it comes soils restoration time and whenever possible, the topsoil and overburden or sterile material, which are found above the mineralized layer, must be deposited back in the same sequence in which it was removed, especially when it is not homogeneous, this will guarantee that the best material for integral recovery it is closer to the surface since the pursued objective is recovering strata configuration as close as possible to the natural profile of the soil.

Besides the call for a review of current legislation, this proposal suggests, among other things, taking into account the following specific aspects: 1.- Training and education for mining workers and mining communities regarding the application of efficient processes on rational profit of natural resources, social-economic aspect, effective administration, financial management, as well as integral health. 2. Soil restoration & preservation from degradation and erosional process. 3.-  Reforestation. 4.- Restoration of biological processes. 5.- Preservation and recovery of aquatic and terrestrial habitats. 6.- Landscape restoration.

It is important to highlight that, for this scale of mining, in the options exposed in the second stage of this proposal, in which areas would be opened for ASM in which reserve estimates have been previously made, exploitation plans and closure of mines plans framed in the environmental impact study must be made, which must rigorously contemplate the costs required for all plans to be carried out as planned, of course, such costs must be considered in the economic feasibility study to determine the feasibility of undertaking the project, the decision could be made based on a cost-benefit analysis.

What has been stated in paragraphs 2 to 5 and 8 to 10 relative to the transitional period should be sustained in this other modality of ASM operations.

Taxes should not be levied on the mining production of artisanal and small-scale miners, but they must pay the costs of public administrative management of their operations, and must also be deducted them when selling their productions, a percentage that must be directed to a social investment fund to benefit the community(ies) close to the extraction sites, such funds would only use the money for projects approved by a simple majority in each community and could only be projects aimed at the comprehensive improvement of the quality of life of the communities and the socioeconomic sustainability of the region.

Such funds should have an Administrative Council made up of a member of the community (elected by two-thirds of the adults of the community and revocable at any time with 2/3 of the votes of the adults of the community), a representative of the mayor’s office appointed by the Municipal Council and another member designated by the institution with competence in mining whose appointment has been published in the Official Gazette of the Republic.

The administration of the projects would be carried out by members of the communities, if they are proven trained to administer, otherwise, they could contract the administration to natural or legal persons, in any way, those who administer projects will be accountable to the Administrative Council.

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