Medium-scale Mining Research Articles

GOLD MINING IN ECUADOR: MATHEMATICAL ANALYSIS FOR THE CLASSIFICATION AND DENOMINATION OF THE ACTIVITIES ACCORDING TO THEIR PROCESSING CAPACITY

Mining is an economic activity that involves extracting, exploiting, and using minerals for commercial purposes. Globally, its growth has been steady in recent decades due to the demand for various luxury items and industrial projects. The main objective of this research was to describe the classification of mining activities in Ecuador and to name the activities according to their treatment capacity. To respond to this objective, a bibliographic review was conducted together with the technique called expert judgment. The results show that in Ecuador, mining activities include four classes: artisanal or subsistence mining, small-scale mining, medium-scale mining, and large-scale mining, based on the levels of daily production that a mine can have.

Criminal Law Enforcement against Illegal Nickel Ore Mining (A Case at Resort Police of Kolaka Utara)

The crime of illegal nickel ore mining is a crime in the mining business carried out by individuals, groups of people, or companies/foundations with legal entities in which their operations do not have a legal permit from government agencies based on the applicable regulations threatened by the criminal sanctions for anyone who violates the prohibition. Article 38 of Law Number 3 of 2020 concerning Mineral and Coal Mining states that “Mining business actors include business entities, cooperatives, and Individuals. Accordingly, mining actors can be grouped with large-scale mining, medium-scale mining, and small-scale mining in the form of community mining. This research used an empirical legal research method to obtain primary data through observation and interviews in Sulawesi Tenggara related to the enforcement of criminal law against illegal nickel ore mining (a case study at the regional police of Kolaka Utara). With the change in the legislation regarding mining itself, the government with the Regional Police of Sulawesi Tenggara must have controlled and eradicated the illegal mining that occurred in Sulawesi Tenggara, included Kolaka Utara. Accordingly, the research problems are 1. What are the police efforts regarding the law enforcement for the criminal act of illegal nickel ore mining at the regional office of Sulawesi Tenggara? 2. What are the factors that hinder the police in enforcing the criminal act of illegal nickel ore mining? Law enforcement is an attempt to bring the ideas of justice, legal certainty, and social benefits into reality. Law enforcement is essentially a process of an embodiment of ideas. Enforcement is the process of making efforts to establish or functioning the legal norms as guidelines in legal relations in social and state life.

Empleo y salarios en la micro, pequeña y mediana minería mexicana a inicios del siglo XXI

A partir de información estadística principalmente de los Censos Económicos se analizan las transformaciones en la micro, pequeña y mediana minería fruto del cambio de modelo económico mexicano iniciado a finales del S. XX y caracterizado por la liberalización de la economía y la apertura al mercado internacional. Para la micro y pequeña minería ello supuso su expulsión de la minería metálica y su reclusión en la minería no metálica con importantes consecuencias en el empleo, la subcontratación o los salarios al quedar al margen de la minería más redituable y que ha experimentado un mayor crecimiento a inicios del S. XXI. Por su parte, la mediana minería ha ido adquiriendo características que la aproximan cada vez más a la gran minería: mayor implicación en la minería metálica, y mayor subcontratación, salarios, activos y relevancia de la inversión extranjera.

‘Centres of excellence’ for artisanal and small-scale gold mining in Tanzania: Assumptions around artisanal entrepreneurship and formalization

The Africa Mining Vision reiterates the importance of training centres or ‘centres of excellence’ (COEs) for artisanal and small-scale mining but historically, these have had mixed results, partly due to a lack of understanding of demand for services. Recently, understanding of artisanal and small-scale mining (ASM) organizational and financial structures has improved, allowing for a more nuanced comparison of formalization policies that emphasize the ‘entrepreneurial’ nature of ASM operators and those that foreground the importance of poverty as a driving factor. With World Bank support, Tanzania has recently established several COEs including two for the artisanal and small-scale gold mining sector. This article examines the potentials of these centres, based on key informant interviews, as well as a literature review of experiences from other African countries. Further, we analyse activities planned at COEs, within the Tanzanian institutional and policy context, which tends to treat ASM as ‘entrepreneurs’. We explore implications of the Tanzanian approach for potential formalization of ASM and transformation of ASM operators into medium-scale mining firms; and identify some institutional tensions and risks involved in implementing the COE approach.

Is Afghanistan’s mineral wealth best left in the ground?

This paper proposes a re-evaluation of the consensus on large scale extractives led development in Afghanistan. The paper builds on existing research which has focused on mitigating the downside risk of mineral extraction. The study asks if the benefits accrued to the country’s current and future citizens would be greater if large-scale exploitation were postponed or a different approach to maximising the value of the country’s sub-soil assets taken. The paper examines the opportunity presented by large scale extraction and illustrates that the economic benefits which should result from this approach are unlikely to be realised due to governance gaps. Economic, social and environmental risks of large-scale mining are found to be significant. These risks are intensified by the limited capacity of the government of Afghanistan to mitigate these risks through good governance. The paper proposes and evaluates an alternative model for harnessing Afghanistan’s mineral wealth: labour-intensive small and medium scale mining, which is more suitable to Afghanistan’s specific contextual factors. It argues that although challenges of small and medium scale extraction exist, this approach should be prioritised over large-scale extraction in Afghanistan, until a time when the use of revenues from large scale mining can be maximised.

Diseño geotécnico de pilares en minas subterráneas de vetas auríferas en casos de Colombia

Se presenta un método empírico-analítico para el diseño de pilares de rocas en la minería subterránea de vetas auríferas en Colombia, que parte de la observación de casos en algunas de las condiciones geológicas de mayor producción en el país y otras experiencias internacionales. La propuesta es centrada en la observación de los mecanismos de ruptura de pilares existentes, en levantamientos de campo, en mecánica de rocas experimental y en análisis estático. La definición del tamaño del pilar se fundamenta en el cumplimiento de requerimientos de estabilidad por evaluación entre la resistencia disponible y los esfuerzos actuantes. El método es expuesto con la intención de facilitar su adopción por parte de la pequeña y mediana minería.

The Grain Size Distribution of Blasted Rock

The determination of the grain size distribution of blasted rock exceeds the capability of an analytical sieving machine which only gives reliable results within a range of 63 μm to 125 mm. Other sophisticated methods are often not available for particle size measurement in coarse-grained applications in medium scale mining. Therefore, an alternative low cost method to investigate the grain sizes of blasted rock is introduced which can cover a range from 63 μm at the lower end without an upper limit. Three different options to examine blasted dolomite grains are investigated and combined with sieve analysis to determine a complete sieving equivalent grain size distribution. Comparison with results of a technical sieving shows that this method gives a good approximation of the size distribution, improving the possibilities for design of mineral processing equipment.

Prediction of acid mine drainage generation potential of various lithologies using static tests: Etili coal mine (NW Turkey) as a case study.

The Etili neighborhood in Can County (northwestern Turkey) has large reserves of coal and has been the site of many small- to medium-scale mining operations since the 1980s. Some of these have ceased working while others continue to operate. Once activities cease, the mining facilities and fields are usually abandoned without rehabilitation. The most significant environmental problem is acid mine drainage (AMD). This study was carried out to determine the acid generation potential of various lithological units in the Etili coal mine using static test methods. Seventeen samples were selected from areas with high acidic water concentrations: from different alteration zones belonging to volcanic rocks, from sedimentary rocks, and from coals and mine wastes. Static tests (paste pH, standard acid-base accounting, and net acid generation tests) were performed on these samples. The consistency of the static test results showed that oxidation of sulfide minerals, especially pyrite-which is widely found not only in the alteration zones of volcanic rocks but also in the coals and mine wastes-is the main factor controlling the generation of AMD in this mine. Lack of carbonate minerals in the region also increases the occurrence of AMD.

Change detection and visualization of acid mine lakes using time series satellite image data in geographic information systems (GIS): Can (Canakkale) County, NW Turkey

Can, a county in the province of Canakkale, is one of the most prominent coal mining districts in Turkey. Many mining companies have been operating coal deposits for power generation and district heating in this region since 1980. Generally, small and medium-scale mining companies operate for short periods and abandon the operational land without providing any rehabilitation. Human intervention in the natural structure and topography of the earth surface causes large holes and deterioration in these areas. Artificial lakes occur because of surface discharge and underground leakage into abandoned open pit mines with high lignite sulfur content (0.21–14.36 wt %). Furthermore, these lakes gain acidic character due to acid generation from pyrite oxidation. Acid mine lakes are highly acidic (pH < 3.05) and have elevated concentrations of \({\text{SO}}_{4}^{2 - }\), Fe and some metals. The main objective of this study is to evaluate the environmental conditions and demonstrate the development of a monitoring system for their possible changes in the acid mine lakes of the open cast lignite mining area on a regional scale. For this purpose, the data received from remote sensing satellites were used. Areal change detection and perimeter changes of nine acid mine lakes caused by coal mining companies in Can from 1977 to 2011, were determined using Landsat, Quickbird and Worldview satellite images. As a case study, an area of 9 km2 was chosen for the variety of acid mine lakes. Using GIS software, satellite images were analyzed in time series, borders of acid mine lakes were digitized and converted into vector data format. At this stage, prior to the digitization, in order to create contrast on the satellite images, “stretch type” and “stretch values” were changed. The areal and perimeter changes were computed and presented via tables and graphics. In addition, thematic maps of the acid mine lakes were created and visualized. The results show that the number of acid mine lakes increased and these caused environmental risks due to their hydrochemical properties and areal increments.

Artisanal and small-scale mining as an extralegal economy: De Soto and the redefinition of “formalization”

This paper addresses the role of formalization in artisanal and small-scale mining (ASM) in sub-Saharan Africa, focusing specifically on Uganda. Most ASM activity occurs outside mainstream legal economies, occupying a hazy world of informal, yet essential, economic activity. There is an emerging consensus that formalization must be part of any strategy to develop the ASM sector. However, the meaning of formalization is not always clear; nor how formalization contributes to economic development. While formalization can be defined in a number of ways, it is argued here that formalizing ASM should be understood in the context of Hernando De Soto's theory of “extralegality”. In this framework, formalization is the means of absorbing existing customary practices—developed informally by miners—into the mainstream of a country's legal and economic affairs. This concept of formalization is applied to the case of Uganda, where, despite official formalization policies on the books, ASM continues to operate outside the formal economy. It is argued that to make formalization work, miners must also be “capitalized” in ways that permit them to move from transient artisanal mining, to more sustainable small- and medium-scale mining. International development organizations can help to facilitate the transition of ASM from an extralegal to a legal economy by creating revolving loan funds, and helping to carry the risk of lending money to miners.

Mercury contamination of alluvial sediments within the Essequibo and Mazaruni River Basins, Guyana

Small- and medium-scale mining operations in Guyana have increased significantly since the late 1980s. The majority of these gold mining operations utilize mercury (Hg) amalgamation methods in the recovery process, raising the question as to the significance of Hg inputs to the environment from mining activities. In March and April, 2001, 168 samples were collected from floodplain, sand bar, and channel bed deposits along a 350 km reach of the Mazaruni River and a 160 km reach of the Essequibo River. Distinct trends in the geochemical data suggest that much of the Hg found in the alluvial deposits is related to anthropogenic sources, including (1) Hg concentrations in floodplain, channel bed and sand bar deposits locally exceed background values defined by ferralitic soils; (2) core data reveal that Hg concentrations within floodplain deposits have increased in recent years; and (3) high Hg concentrations along the channels can be attributed to the influx of material from tributaries affected by mining operations, or to mining activities along the rivers. Recent investigations in Amazonia have argued that Hg from amalgamation mining represents a small portion of the total Hg load to riverine systems, the majority coming from the erosion of Hg enriched upland soils within deforested terrain. Geochemical data from the Essequibo and Mazaruni Rivers suggest that Hg from mining may be a more significant source in Guyana where large-scale deforestation is limited. However, it is unclear whether the increased Hg represents the direct input associated with the amalgamation process, or Hg associated with the erosion of soils and sediments that results from activities that accompany mining.