Global risk score of the territorial mining scenarios and multi-actor weighting

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The territory system: French Guiana and Mana river basin

Chapter 3 presents the territory system on which the methodology is applied. Because of the territorial dimension of our approach, a brief but general overview of FG must be given. Then, a smaller spatial unit is chosen at the river basin scale and its human and ecological features described to give a perspective of the socio-ecological vulnerability of the territory.

General presentation of French Guiana and its specificities

FG is a French Overseas Territory and Department located in the northern hemisphere, near the equator, on the northern Atlantic coast of South America. With a surface of approximately 84,000 km2, it is the largest department of France – the only one in South America – and the larger outermost region within the European Union (EU) (Papy, 1955). FG is at approximately 7,000 km far from Metropolitan France and it is located between the rivers of Maroni and Oyapock which separate it respectively from Suriname and Northern Brazil (Fig. 16). Its features concern a transversal range of aspects which must account for:
– Its localization within the Amazon rainforest, in a sensitive region from a hydrological, geological and environmental point of view (Galochet and Morel, 2015)
– Its colonial history that reflects a currently complex political, economic and socio-cultural context and results in a strong dependence towards Metropolitan France through public policies that address the socio-economic and ecological challenges of the territory (e.g. exponential demographic growth, land-use conflicts, high non-employment rates) (Barret, 2001; Piantoni, 2009; Oder, 2011).

Environment of French Guiana

The geo-environmental context of FG is no different from its neighbouring countries and is strictly related to the geological settings of the Guiana Shield and its equatorial climate.
– Geology of FG is presented and discussed by a wide range of scientific literature (Delor et al., 2003b; Milesi et al 2003; Cassard et al., 2008) and grey papers (Milesi and Picot, 1995; Degay et al 1997; Théveniaut et al., 2011). Two greenstone belts of low sedimentary and volcanic units cross the territory from west to east in its northern and southern regions. It is mainly in these formations that gold mineralization took place. A simplified geological map of FG is available in Appendix 4.
– An equatorial-wet climate due to its position within the Intertropical Convergence Zone. Because of its position, FG has (low pressures, average temperatures at ~26,5 °C and variable rainfall intensity between 1,700 to 5,000 l/m2 per year). (Barret, 2001; Lecomte et al., 2011). (
– A territory divided between the coastal plain, called “lowlands” (4% of the territory) and the inner regions, or “uplands” (96% of the territory) and reliefs globally moderate with some punctual sloping areas (the Inini-Camopi mountains, reaching 850 m, hills, inselbergs).
– Hydrogéologic and hydrologic resources divided in several groundwater bodies (85,000 km2 in confined aquifers) and a highly dense and tufted network of surface water bodies (almost 20 000 km of length) spread across the territory (Barret, 2001; Asconit, 2013; DEAL, 2013). Actual renewable water resources (i.e. the total amount of a country’s water resources) per habitant in FG are estimated to be more than 700,000 m3/year (less than 3,500 m3/year in Metropolitan France) (OEG, 2016 ). Surface water streams are mainly affected by the release and deposits of important quantities of total suspended solids (TSS) (Barret, 2001), due to natural or anthropic causes, including gold mining. Finally, the only plane surface water body in FG is the Petit-Saut hydroelectric dam reservoir (Fig. 16). More details about Petit Saut and its role in vectorizing, for instance, mercury-related risks can be found in Sissakian (1992); Calmont (2001); Muresan (2009), Pestana et al., (2019).
– Soils very heterogeneous, with a great range of properties. The predominant soil types, as shown by a simplified soil map provided by Blancaneaux, (2001) (Appendix 4), concern poorly developed soils, podzols, hydromorphic soils (mainly located in the lowlands) and a great variety of oxisols and ultisols occupying ancient lowlands and mainly the uplands. The main common features of these soils zones are their high degree of weathering, their sensibility to erosion, their low fertility and a mostly acidic pH. (Turenne, 1973; Betsch, 1998). However, soil resources in FG should be more pertinently be acknowledged.
– More than 90% of the territory covered by tropical rainforest (Cassard et al., 2008; De Santi et al., 2016), making of FG a world-widely recognized high-biodiversity wilderness area within the Amazon rainforest region (Galochet and Morel, 2015). Indeed, biodiversity is maybe the environmental component the most discussed in FG, especially when it comes to gold mining-related impacts. Various compilations of the floristic and faunistic richness of FG are available (Barret, 2001; DEAL, 2014; ONF, 2015; Stier et al., 2020). The ecological patrimony of FG encouraged public authorities to create, during the years, a great number of protected areas, including three RAMSAR zones, 170 ZNIEFF areas and one Amazonian Park (Appendix 4) (Chaneac and Legrand, 2009; DEAL, 2014; Galochet and Morel, 2015; CTG, 2016).

History, society and economy in French Guiana

Gold mining affects the socio-ecological dynamics in FG and represents an activity that shaped the human component of FG, as it has been widely deepened by Jebrak et al., (2020) Therefore, risks related to gold mines vary considerably based on the features of the societal context where they are performed.

Human societies and history

Almost all the human settlements of FG concern the coastal area, with one first main cluster in the capital Cayenne, but also Kourou or Mana – and the riverine regions of the Maroni – with the second main cluster of Saint-Laurent du Maroni – and the Oyapock. FG has one of the highest demographic growth rates in France (Millet, 2018). According to a report of the French National Institute of Statistics and Economic Studies (Insee), population increased from 27 863 in 1954 to 269 352 in 2016 (Raimaud, 2018) and may reach more than 500 000 people in 2050 (Léon, 2010; Demougeot and Baert, 2019). Cayenne more than tripled its surface between 1946 and 1998 (Barret, 2001).
Because of its history, FG population is extremely diversified. It mainly includes Creoles (i.e. people born in the colonial territory), French Metropolitans, Bushinengue (i.e. descendants of black slaves carried from Africa to the colony), six groups of indigenous people of America but also important communities of Brazilian, Hmong (mainly from Laos), Chinese, Javanese, Lebanese and Indo-Caribbean people (Joshua Project, 2015). Such multi-culturalism is discussed by several authors (Papy 1955; Jolivet, 1971; Collomb, 1999; Fouck, 2000; Elfort, 2010) and it poses important challenges for the uniform application of public policies and land-use regulations (Grenand et al., 2006). The cohabitation of these different cultures might be on occasions the source of social tension concerning land property rights. Indeed, French administration historically took over the Native Americans and progressively transformed the territory into a “plantation model” where a process of “francization” of local people was performed through Christianity and property rights (Barret, 2001). At the same time, the slavery system shaped the population into “white” Europeans, Native Americans, African slaves and Creoles. Such dynamics must be considered at the scale of the three Guianas, since it produced internal migration flows of Native Americans and African slaves. For instance, the rebellions of Africans against slavery led to the development in FG and Suriname of new black communities (the Bushinengue). In 1848, slavery was abolished, and French administration continued the francization of the newly-freed slaves as sort of “social promotion” (Barret, 2001). If FG was a well-known destination for political prisoners since the French Revolution, under the 1854 “deportation decree” by Napoleon III, FG became officially a penal colony, leading to the construction of several labour camps, called “bagnes”. Massive groups of people France were sent from the Metropolis to FG, as deported or as part of the colonial administration. After the beginning of gold exploitation in 1855, the fist “gold rush” added more migration flows across the region and the reduction of Native Americans at the beginning of 1900. IIWW and the economic crisis generated the worsening of living and social conditions in FG. Finally, FG became a French department in 1946 (again, after the short period in 1797) as integral part of French Republic and submitted to the same regulatory framework of the Metropolis.
The demographic rate and the high diversification of FG society is due as well to these historical conditions (Piantoni, 2009). For instance, in 1999 more than one third of the population was foreigner. Two main factors are related to such migratory flows: firstly, the physical fuzziness of FG boundaries with Surinam and Brazil (Barret, 2001), leading to massive flows, especially of illegal miners. Secondly, the gross domestic product (GDP) is a half lower than in Metropolitan France (Piantoni, 2009; Insee, 2017). As the other French Overseas territories, FG relies on public transfers from Metropolitan France which create an “artificial prosperity generating internal freezing and exacerbating nationalist identity reactions” (Barret, 2001). Therefore, FG has higher living standard and regional GDP than the neighboring countries (IEDOM, 2014) making it more attractive to the neighboring communities. Moreover, several European aids are provided for the region (IEDOM, 2016). Therefore, FG is the destination for several migrants seeking for better opportunities, including illegal gold mining.


Short overview of the main economic activities

In 2016, gold mining was representing approximately 1% of the GDP of FG, with 500 declared employees while the informal gold mining sector is up to 10 000 estimated workers (IDEOM, 2016). The presentation of the other different economic activities in FG is available on the portal of French institute for the statistical and economic studies ( A general overview is also presented by Barret (2001), IEDOM (2016) and in a recently published report by Deloitte (2018) that compares different future scenarios of economic development in FG.,
The unemployment rate in FG was up to more than 23% in 2016 (IDEOM, 2016), one of the highest in France. If most of the jobs opportunities are provided by the public administration sector, representing 41% of the total employment and 35% of the global GDP, other several activities play an important role in the economic dynamics of FG. A short list will present the main sectors:
– Agriculture and farming: more than 30 000 hectares in FG are destined to agriculture (Deloitte, 2018). The traditional “slash-and-burn” agriculture is still the most practiced and covers almost 80% of the total agricultural surface (Demaze and Manusset, 2008; Deloitte, 2018).
– Fishing is also an important sector even if currently illegal fishing activities produce three times more than the legal ones (Deloitte, 2018).
– Wood production provides around 500 direct jobs (CTG et al., 2018) and represent an important potential for FG.
– Construction represents 8% of the total value added in FG (IEDOM, 2016).
– Industrial activities, other than gold mining, cover a wide range of sectors such as the chemical transformation, food production, transport, energy, etc.
– After the development in 1968 of the Guiana Space Centre (CSG), space industry has been representing a boosting factor both for the city of Kourou, where the population raised from 3000 to more than 25 000 people in 50 years but also for the entire region (Charrier et al., 2017).
– The energetic sector as well provides important outcomes since more than 64% of the total electricity is produced through renewable resources (CTG, 2016).
– Tourism counts approximately 100 000 visitors per year in FG, mostly for business purposes (Deloitte, 2018).
– Research and education count different structures in FG (INRAE, CNRS, IRD, SEAS) and one University in Cayenne, with more than 3 000 students in 2012 (Insee, 2014).

Selection of the spatial scale: Mana river basin

Our study is conducted at the scale of a river basin (RB), the area where all streams drain to a common terminus (Molle et al., 2007). A RB is considered in this study as a territory system, thus as a socio-ecological functional unit that has the capability to provide ecosystem services and regulate human life through the meeting of societal needs (see Chapter 1).
The choice of this scale is due to the significative importance of water management at the river basin in FG where the hydrographic network is considerably dense and plays a key role in the daily life of local population. Furthermore, there is a tight relationship between mining activities
– particularly gold mining – and water management, especially under the climatic conditions of FG. The structure of the basin and of the hydrographic network have a strong influence on the functioning of a mining project, starting with the localization of the mine site, its construction and water and waste management (ICMM, 2015). For instance, Kossoff et al., (2014), suggest that the parameters to assess the consequences of a tailings dam failure and the remediations measures to implement, depend on the features of the RB.

Table of contents :

Part I – General context and objectives of the thesis
Chapter 1. Mining, territory and risks
1. The mining system
2. Mining performances at the territory level: a call for sustainability in the mining sector
3. Risks associated with mining projects
4. Existing methods for risk assessment in the mining sector and their gaps
Chapter 2. Objectives of the thesis and development of a methodology via the application on a case-study
1. Our approach and objectives of the study
2. Theoretical development of the methodological framework
3. Criteria used for the selection of a case-study
Part II – Application on gold mining in French Guiana: definition of the systems and development of the scenarios
Chapter 3. The territory system: French Guiana and Mana river basin
1. General presentation of French Guiana and its specificities
2. Selection of the spatial scale: Mana river basin
3. Actors considered and temporal dimension of the application
Chapter 4. The mine system: overview and classification of gold mining in FG
1. Overview of gold mining across the world
2. Gold mining in the Guiana Shield
3. Gold mining in French Guiana
4. Gold mining in the Mana RB
5. Classification of gold mines and development of standardized project-types
Chapter 5. Development of the Territorial Mining scenarios (TMS)
1. Territorial objectives and Territorial Mining Scenarios (TMS)
2. Fictional localization of the gold mining projects
Chapter 6. Risk identification and risk scenarios development
1. Risk identification for each gold mine-type in French Guiana
2. Accidental Risk scenario (RSa) development
3. Ordinary Risk scenario (RSo) development
Part III – Application on gold mining in French Guiana: assessment of the risk scenarios and TMS scoring
Chapter 7. Assessment of the accidental Risk Scenario (RSa)
1. Assessment of dam failure consequences through vulnerability indicators
2. Calculation of the flooded area
3. Mapping socio-ecological vulnerability to flooding
4. Estimation of the consequence scores of the RSa
5. Probability assessment and risk estimation
6. Calculation of the RSa risk score for each TMS
7. Alternative estimation of the RSa score for each TMS
Chapter 8. Assessment of the ordinary risk scenario (RSo)
1. Evaluation of the positive and negative consequences for each TMS
2. Aggregation of the risks and final score for each territorial mining scenario (TMS)
2.1. Aggregation of the positive and negative consequences
2.2. Aggregation of positive and negative consequences and final score
Chapter 9. Global risk score of the territorial mining scenarios and multi-actor weighting
1. Assessment of the global risk score of each TMS
2. Multi-actor assessment of the relative importance of each consequence
Part IV – Discussion of the approach proposed in this study and its application
Chapter 10. Discussion on the application of our approach to the French Guiana gold mining sector
1. The influence of system definition on the final scores
2. The influence of the chosen territorial mining scenarios on the results
3. Rapidity and reliability of the RSa and RSo scores assessment
4. Final TMS scores and weighting coefficients
5. Comparison of the territorial scenarios: which scenario is the “best”?
Conclusion and perspectives for the application of our approach in FG gold mining sector
Chapter 11. Advantages, limits, perspectives of our approach and concluding remarks
1. Added value of the approach proposed in this study
2. Geospatial issues of the approach and its application
3. Future perspectives of our approach


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