Evaluation of the Efficiency of Implementation of the Sustainable Development Program at Nickel-Cobalt Ore Mining Enterprises

Abstract

The environmental crisis and the accelerated depletion of natural resources require strategies that balance economic growth and environmental protection in accordance with the principles of sustainable development. In this context, the mining industry, despite playing an important role in economic development, has significant negative impacts. The application of sustainable practices helps to mitigate these impacts. This study evaluates the effectiveness of rehabilitation measures applied in the abandoned mine of Punta Gorda, Cuba, using an integrated system of socio-environmental and economic indicators. The methodology, based on a procedure for socio-environmental and economic management in mine rehabilitation, comprises six stages and fourteen steps, including the valuation of ecosystem goods and services, economic valuation, and monitoring of rehabilitation results. Key results show a 5.95% improvement in economic efficiency in 2023, partial recovery of the ecosystem after rehabilitation, and improved health of mine workers. The study emphasizes the importance of multidimensional assessment tools to align mine rehabilitation with the Sustainable Development Goals (SDGs), particularly SDG 11, and highlights the role of corporate social responsibility in improving the well-being of the mining community. The proposed framework provides a replicable model for sustainable mine rehabilitation, emphasizing the integration of economic, social, and environmental indicators.

1. Introduction

The growing environmental crisis and the accelerated depletion of natural resources underscore the urgent need to adopt strategies and policies that harmonize economic growth with environmental protection [1,2,3,4], in line with the principles of sustainable development [1,4,5]. In this regard, the 2015 Sustainable Development Summit formulated the Sustainable Development Goals (SDGs) for the period 2015–2030 to promote environmentally responsible practices, optimize resource management, and encourage the use of renewable energy [6,7] and clean technologies [8,9].

Within this framework, “Goal 11: Sustainable Cities and Communities” emphasizes the strategic role of businesses in this transition [10,11,12]. This goal encourages organizations to incorporate sustainable management practices into their operations, while emphasizing the importance of allocating a portion of economic profits to initiatives that contribute to the growth of local and national economies [4,13].

The mining industry is at the center of governments’ attention for the implementation of the SDGs [14]. Despite being critical to national [15,16] and global economic development, the sector causes serious environmental damage [12,17] such as deforestation, air pollution, loss of biodiversity [18,19] and diseases in communities near mines [20,21]. However, it is argued that these impacts can be minimized through sustainable development practices that focus on economic viability, environmental protection, and social well-being [22]. This requires governments to develop regulations that establish corporate responsibility for environmental protection and efficient resource utilization.

In this regard, several studies emphasize the role of corporate social responsibility [5,7] in addressing environmental, economic, and social issues in mining communities, and the need to balance environmental security, inclusive economic development, and citizens’ rights [23,24]. On the other hand, strategies have been proposed to improve the energy efficiency of companies [25], including the use of renewable wind and solar sources [26], with the installation of wind turbines, photovoltaic systems, and energy storage systems [27]. In addition, incentives have been proposed for mining companies to invest in artificial intelligence [28] and policies to increase transparency and accountability in the mining sector [29].

Other studies highlight circular economy solutions [30,31], such as the use of renewable energy [32,33], wastewater recovery [8,34], reuse and recycling of mining waste [30,35], and recovery of critical metals from mine tailings through life cycle service assessment (LCSA) or electrochemical processes, as well as the implementation of robust legal frameworks and incentives for integrated waste management [12,36,37].

However, the need to measure the effectiveness of actions taken within the framework of sustainable development in the mining industry has led to new studies, such as a study by do Carmo Silva and da Silva [38], in which they develop a methodology to evaluate performance indicators in an iron ore mine in Pará, Brazil, in order to understand whether these indicators guide the mine’s activities towards achieving the SDGs, identifying the indicators that are most relevant in the context of adherence to the SDGs and those that should be prioritized for monitoring and action. Similarly, ref. [39] uses 11 SDG indicators assessed on 15 dimensions focused on the development of mining communities in South Africa, demonstrating differences in the living standards and well-being of communities. In [40], a system of indicators is proposed to measure the sustainable development index of a mining company based on the evaluation of geological and mining indicators, economic growth, compensation, and development.

In Cuba, studies have been conducted to find strategies for the development of sustainable mining, mainly in the nickel industry [41]. They range from environmental approaches in mining to policies implemented in mining companies and their integration with sustainable development goals. Research has also been carried out on the rehabilitation and restoration of mined areas. In this sense, the work of [42]. proposes a procedure for the environmental rehabilitation of Cuban open-pit polymetallic pyritic deposits to contribute to reduction of environmental liabilities and potential sources of degradation. Similarly, work by [43] presents a procedure to recover mined areas in quarries of construction materials in Santiago de Cuba to contribute to improvement of environmental, social, and economic qualities in areas affected by mining activities. The reviewed studies focus mainly on the aspect of the environment, considering ecological and forestry aspects; although they report results which impact economic and social well-being, indicators to measure their effectiveness are not applied.

According to the authors, studies carried out in the Cuban context have lacked tools to evaluate the effectiveness of actions implemented in frameworks of sustainable mining development.

Thus, the objective of this article is to evaluate the effectiveness of the implemented actions for the reclamation of the Punta Gorda abandoned mine through a system of socio-environmental and economic indicators.

To achieve this objective, the following research tasks are proposed:

• To develop indicators to evaluate the effectiveness of the implementation of the ecosystem restoration project in the abandoned mine of Punta Gorda.
• Evaluate, according to the selected methodology, the effectiveness of measures implemented within the framework of sustainable development programs of companies for the abandoned mine of Punta Gorda.

2. Materials and Methods

The methodological framework is based on the procedure for socio-environmental and economic management of abandoned mine rehabilitation developed by [44]. This procedure was applied during the rehabilitation of an abandoned mine site located in the Punta Gorda nickel and cobalt deposit in the municipality of Moa in the province of Holguin. The procedure consists of 6 stages and 14 steps, as shown in Figure 1.

Description of the Implementation Stages of the Procedure

During the first stage, program participants (e.g., managers and technicians) received training on the socio-environmental and economic management procedure for abandoned mine site rehabilitation, covering all stages and steps.

The next stage consisted of two steps: identifying the key characteristics of the study area and identifying the ecosystem goods and services that comprise it and quantifying them using a total economic valuation method consisting of direct use value, indirect use value, option value, and existence value [44].

The total economic value is defined in [44], which states that the total economic value of any good or ecosystem service can be composed of different values: some tangible and easily measurable, others intangible and difficult to quantify. It is the sum of direct use, indirect use, option, and existence values that create the total economic value of a resource.

The following equation is used to determine the total economic value:

$$VET=VUD+VUI+VO+VE$$

(1)

where

• VET: Total economic value
• VUD: Value in direct use
• VUI: Indirect use value
• VO: Option value
• VE: Value in existence

• Direct use value includes ecosystem goods and services that humans can use directly and that have a quantifiable market value, such as timber extraction, water, fishery products, and recreation and tourism services.
• Indirect use value includes environmental services that support economic activities but do not have a market price, so their value is measured by their contribution to economic activities that have a quantifiable value (e.g., pollination for agriculture) and by the value of substitute products that perform similar functions (e.g., wastewater treatment plants).
• Option value is the value that society is willing to pay to preserve a natural resource for future use. This value relates to the potential of an ecosystem to generate scientific, health, or economic benefits that have not yet been utilized.
• Existence value is the intrinsic value associated with the conservation of biodiversity, genetic information, or habitats for endangered species.

The third stage, a two-step process, involved consulting with experts to determine the environmental impacts of the mine and assess the ecosystem goods and services affected by mining. The Delphi method was used to identify the environmental impacts caused by mining activities, taking into account the following steps: 1. Preparation of the questionnaire; 2. determination of the number of experts; 3. selection of experts; 4. conducting rounds to obtain expert consensus; and 5. evaluation of results based on hypothesis testing. The evaluation of ecosystem goods and services was based on the total economic value method.

The fourth stage involved determining the future use of the abandoned mine, developing objectives for the rehabilitation process in the short-, medium-, and long-term, and developing an economic budget for the rehabilitation of the mine.

The fifth stage included conducting rehabilitation activities at the abandoned mine, evaluating the rehabilitation results using social, environmental, and economic indicators, and assessing the economic, social, and environmental benefits derived from the procedure.

The final stage included monitoring compliance with the rehabilitation process and developing a corrective action plan based on analysis of the results obtained.

3. Results

3.1. Previous Training

Training of mine management in the application of socio-environmental and economic management procedures for mine rehabilitation:

In Step 1, training activities were conducted for the managers and the work group responsible for implementing the socio-environmental and economic management procedure at the abandoned mine. Specialists with relevant expertise delivered three lectures on the possible impacts on ecosystems resulting from mining operations, the existing limitations in the methodologies and procedures governing the mine rehabilitation process, and the need to incorporate socio-environmental and economic management into the mine rehabilitation process as a tool to promote rehabilitation in accordance with sustainable development principles.

Creation of the interdisciplinary working group:

In a meeting held with the company’s board of directors, the members of the interdisciplinary working team were proposed and approved to oversee the implementation of the proposed procedure.

Training of the interdisciplinary working group in the stages and steps of the procedure for the socio-environmental and economic management of mine rehabilitation:

Working sessions were held with the participation of specialists, where the procedure, its stages, and steps were presented and analyzed to ensure its proper implementation.

3.2. Characterization of the Ecosystem Under Study

The ecosystem under study related to the Punta Gorda mine is located east of the town Moa in Holguin Province, within the Moa-Baracoa Mountain range, bounded by the coordinates X, 509700–513500, and Y, 279100–282100. Its natural boundaries are the Moa River to the west–northwest, the Jagrumaje River to the southwest, and Los Lirios Creek to the west. The climate of the region is tropical, with an average annual temperature of about 27 °C, ranging from 30 °C to 34 °C in summer to 22 °C to 26 °C in winter. The relief of the territory is mountainous. The hydrogeology is characterized by the fact that the main sources of groundwater are the Los Lirios and Jagrumaje rivers [45,46].

3.3. Identification of Ecosystem Goods and Services

In this step, based on the analysis of information collected by the interdisciplinary working group, ecosystem goods and services were identified in the 5.5 ha site to be exploited in 2022, as shown in Figure 2.

3.3.1. Valuation of Ecosystem Goods and Services

The economic value of ecosystem goods and services was determined prior to the exploitation of the area, taking into account the value of direct use of resources such as timber, carbon, minerals, and fauna, and as well as the value of indirect use of resources such as water, according to current market prices and Cuban legislation. The other goods and services identified were not considered in this study because they did not have market prices to conclude their value.

Timber

In the analyzed 5.5 hectares, 39.27 m³ of timber of different qualities were valued by plot sampling (see

Table 1. Economic valuation of timber by grade. Source: compiled by the authors.

Classification of Wood Species	Amount of Wood (m3)	Average Price (Cuban Pesos)	Economic Value (Cuban Pesos)
Hardwood class B	10.09	1622.31	16,369.11
Softwood with class B	8.29	1032.40	8558.60
Softwood class C	6.23	873.93	5444.58
Firewood	14.66	40.40	592.26
Total	39.27	$3569.05	$30,964.55

), with timber prices set according to Decree 312/2020 of the Ministry of Finance and Prices. As a result, higher-quality wood was valued at 30,372.30 CUP and wood for energy consumption at 592.26 CUP, totaling 30,964.55 CUP.

Carbon

To estimate the carbon sequestered in the soil, studies conducted by the Agroforestry Research Institute of Havana on forest soils with similar characteristics to those of the Punta Gorda site were analyzed and it was estimated that there was 879.95 tons of carbon sequestered in the hectares studied. The value per ton of carbon sequestered was calculated based on the current price at [47]; the equivalent in Cuban pesos was obtained according to the current euro exchange rate (26.1768) for the business sector according to the Central Bank of Cub (see

Table 2. Economic evaluation of carbon sequestration. Source: compiled by the authors.

Carbon Sequestration (tons)	Price (EUR)	Economic Value (EUR)	Economic Value (CUP)
879.95	86.68	76,273.63	1,996,599.63

).

Mineral Resources (Nickel and Cobalt)

To quantify nickel and cobalt, the Punta Gorda mine development project in the study area was utilized, which details the planned reserves for mining for each year. The total nickel and cobalt reserves in the mine area amounted to 5138.55 tons (see

Table 3. Calculation of the number of tons per ore type. Source: compiled by the authors.

Quantity Nickel + Cobalt (tons)	Nickel Efficiency	Cobalt Efficiency	Nickel Quantity (tons)	Quantity Cobalt (tons)
5138.55	0.6802	0.2969	3495.24	1525.63

). The nickel efficiencies established by the company as per the technical and metallurgical conditions were 0.6802 and, for cobalt, 0.2606, hence these values have been adopted for estimation of nickel and cobalt, as shown in the following table.

To calculate the value of the minerals, the prices established in the market by the London Metal Exchange were taken into account, which allowed us to determine a total value of USD 180,960,581.08, with an equivalent in Cuban pesos of 4,343,053,945.92 CUP (see

Table 4. Economic valuation of minerals. Source: compiled by the authors.

Mineral Type	Quantity (tons)	Price (USD)	Economic Value (USD)	Economic Value (CUP)
Nickel	3495.24	21,125.00	73,836,945.00	1,772,086,680.00
Cobalt	1525.63	70,216.00	107,123,636.08	2,570,967,265.92
TOTAL			180,960,581.08	4,343,053,945.92

), taking into account the current exchange rate of 24 Cuban pesos per dollar (USD).

The fauna species inhabiting the area were determined based on the data provided in the environmental impact study conducted by the company Ecology Department GANMA S. A. Fourteen fauna species were identified in the territory, the most representative of which are Anolis porcatus (lizard), Osteopillus septentrionales (banana frog), Chordeiles gundlachii (turtle), Caracolus sagemon (forest snail), Teretistris fornsi (Eastern wagtail warbler), Calypte helenae (zunzuncito), and Amazona leucocephala (Cuban parrot). For their evaluation, prices set by the Triton store, Madrid, Spain, with reference to [48] and reference [49], were used. For species not sold in these stores, a price based on supply and demand on the national market was applied.

The valuation by species resulted in a total of 4142.96 CUP, of which 325 CUP and EUR 146 was the equivalent of USD 3817. 96 at the current exchange rate of 26.15040 CUP in 2022.

Water

The economic valuation of water was based on information provided by the Olguin Water Development Company on the water requirements per year from the Cayo Guan River (10,746 m³) used for construction activities. The cost of this water was obtained by multiplying 10,746 m³/year by 0.70CUP, which was the price per m³ of water established in Resolution 419/2020, giving a total cost of 7522.20 CUP.

Total economic value of goods and services of the ecosystem.

Based on the values obtained for each of the goods and services, the total economic value of goods and services was determined to be 4,345,193,175.26 CUP (see

Table 5. Total economic valuation of ecosystem goods and services. Source: compiled by the authors.

Ecosystem Goods and Services	Economic Value (CUP)
Fauna	4142.96
Wood (m3)	30,964.55
Carbon dioxide	1,996,599.63
Nickel	1,772,086,680.00
Cobalt	2,570,967,265.92
Water	7522.20
Total	4,345,093,175.26

).

3.4. Identification of the Impact of Mining Activities on the Environment in the Study Area

The environmental impact of the area was determined based on the results of interviews conducted with 15 experts, including environmental specialists, geologists, and mining engineers. During this step, an assessment of the impacts of the mine on the physical environment, biota, and social environment was carried out, and 28 types of environmental impacts were identified, of which the following were recognized as the most significant for the physical environment: increased noise levels due to the operation of heavy machinery and truck traffic, changes in topography, increased sedimentation on riverbanks, changes in groundwater recharge and discharge conditions, and increased network of overland roads.

The greatest impacts identified in the biosphere were related to changes in natural ecosystems and the disappearance of microflora and microfauna, loss of species, migration of birds and mammals, and death of reptiles, amphibians, and insects. In the social environment, the most significant impact esd on the health of workers and residents of communities near the mine due to increased noise and dust levels.

3.5. Identification of Ecosystem Goods and Services Affected by Mining and Economic Valuation of Goods and Services Present in the Ecosystem After Mining

Based on site diagnostics, we identified the ecosystem goods and services present after the completion of mining in the 5.5 hectares to be mined in 2022 at Punta Gorda. The impacts on the ecosystem as a result of mining activity were then quantified, and it was determined that all the goods and services that constituted the ecosystem prior to exploitation were affected, resulting in a loss of economic value of CUP 4,345,085,653.06. As for water resources, they were not directly affected because they were within the study area, so the economic value determined prior to exploitation was maintained. As a result of the analysis, the total economic value of the goods present in the ecosystem was determined to be CUP 7522.20.

3.6. Determination of Possible Future Use of the Abandoned Mine

During reclamation planning, possible future uses of the site were assessed, including urban, recreational, urban, forestry, agriculture, conservation and ecological refuge, landfill, and reservoir uses. For this purpose, 24 experts were interviewed and as a result it was determined that the future use of the mine site would be mixed (agriculture and forestry).

3.7. Defining the Objectives of the Mine Rehabilitation Process

The interdisciplinary working group developed short-, medium- and long-term objectives for the mine rehabilitation process.

Short-term goals:

• Prepare the physical condition of the land for reforestation.
• Control erosion processes.
• Treatment and control of contaminated water from the mining process.
• Guarantee seed quality.
• Restoration of topsoil.
• Planting of forest trees interspersed with fruit trees.

Medium-term objectives:

• Eliminate erosion processes.
• Promote restoration of native fauna and flora.
• Maintain plantations with fertilizer.

Long-term objectives:

• Achieve restoration of the natural balance between soil, vegetation, and fauna.
• Commercialization of timber from reforestation.
• Return reforested areas to the Cuban government’s forest fund.

3.8. Development of an Economic Budget for the Rehabilitation of an Abandoned Mine

To achieve the objectives, a Rehabilitation Budget for 2023 was developed by activity (See

Table 6. Mine rehabilitation budget for 2023. Source: compiled by the authors.

Rehabilitation Activities	Price (CUP)	Quantity	Budget 2023
Soil preparation (ha)	4763.00	4	19,052.00
Plantations (ha)	10,385.00	4	41,540.00
Maintenance of plantations (ha)	2921.00	31	90,557.00
Installation of artificial barriers (ha)	27,057.00	3	81,172.00
Seeding of grasses (natural barriers) (ha)	27,106.00	2	54,212.00
Shallow gully correction (units)	2118.00	28	59,304.00
Mid-depth gully correction (units)	3668.00	37	135,734.00
Sedimentation basin maintenance (units)	45,520.00	2	91,040.00
Sediment drainage maintenance (units)	27,725.12	2	55,450.24
Construction of protection trenches (units)	22,198.00	3	66,594.00
Total Amount			694,655.24

)

3.9. Implementation of Rehabilitation Activities

During the implementation of mine rehabilitation tasks, the following actions were taken in accordance with the activities planned for this process.

Technical site preparation

• The surface of the land was modeled as close as possible to its natural form, allowing it to be integrated into the landscape.
• The uneven surface of the exploited hectares was unified.
• Soil heaps were formed with a limit height of 6 m above the level of the surrounding area.
• Topsoil from the clearing was used to cover the surface in the areas to be reforested for reforestation.
• All slopes of the reforested areas were seeded with herbaceous vegetation.

Land Reclamation

• Slopes on active and inactive banks were designed to be stable.
• The maximum upstream slope gradient of the inactive edge slopes was set at ⁰30 to provide stability and reduce gully formation.

Biological rehabilitation of land

• Quality-certified pine, guava, and maranion seeds were selected for planting.
• Two hectares of the rehabilitation area were interspersed with pine and grass (stargrass) plantings to promote soil regeneration and the inclusion of reptiles and amphibians. On the remaining two hectares, species were interspersed with guava and maranion.
• Plantation maintenance was carried out on a monthly basis.
• Organic and mineral fertilizers were applied at an individual dose of 2 kg per plantation.
• Species planting frames were 2 × 2 m to promote growth and adaptation of forest plants.
• Grass and artificial barriers were installed between plantations as a soil protection measure.
• Artificial shelters were built on the 5.5 hectares restored to facilitate the reappearance of fauna.

3.10. Evaluate Rehabilitation Results by Calculating Economic, Social, and Environmental Indicators

To assess the rehabilitation process of the abandoned mine, economic, social, and environmental indicators were used to quantify and then analyze the results obtained. For this purpose, the years 2018 (the last year in which another site related to the study area was rehabilitated) and 2023 (the current year of rehabilitation) were used (See

Table 7. Dynamics of economic, social, and environmental indicators in 2018 and 2023 [compiled by the authors].

Indicators	Equation	Calculation 2018 (%)	Calculation 2023 (%)
Coefficient of efficiency of use of funds for reclamation of disturbed lands	$\mathrm{C}\mathrm{E}\mathrm{F}\mathrm{R}\mathrm{D}\mathrm{L}={\displaystyle \frac{\mathrm{A}\mathrm{R}\mathrm{C}}{\mathrm{P}\mathrm{R}\mathrm{C}}}\times 100$	${\displaystyle \frac{\mathrm{101,543.46}}{\mathrm{116,051.40}}}\times 100\%$ $=87.50$	${\displaystyle \frac{\mathrm{64,913,524.24}}{\mathrm{694,655.24}}}\times 100\%$ $=93.45$
Efficiency of environmental recovery costs for lands to be remediated	$\mathrm{E}\mathrm{E}\mathrm{R}\mathrm{C}\mathrm{R}={\displaystyle \frac{\mathrm{A}\mathrm{E}\mathrm{C}\mathrm{R}}{\mathrm{T}\mathrm{P}\mathrm{B}\mathrm{R}}}\times 100$	${\displaystyle \frac{\mathrm{80,109.25}}{\mathrm{116,051.40}}}\times 100\%$ $=69.03$	${\displaystyle \frac{\mathrm{481,571}}{\mathrm{694,655.24}}}\times 100\%$ $=69.33$
Efficiency coefficient of flora restoration on the territory subject to reclamation	$\mathrm{E}\mathrm{C}\mathrm{F}\mathrm{R}\mathrm{T}={\displaystyle \frac{\mathrm{T}\mathrm{E}\mathrm{F}\mathrm{R}}{\mathrm{T}\mathrm{E}\mathrm{A}\mathrm{F}}}\times 100$		${\displaystyle \frac{4}{5.5}}\times 100\%=72.73$
Efficiency coefficient of fauna restoration on the territory subject to reclamation	$\mathrm{E}\mathrm{C}\mathrm{F}\mathrm{A}\mathrm{R}\mathrm{T}={\displaystyle \frac{\mathrm{T}\mathrm{N}\mathrm{F}\mathrm{S}\mathrm{R}}{\mathrm{T}\mathrm{N}\mathrm{A}\mathrm{F}\mathrm{E}}}\times 100$		$9/14\times 100\%=64.29$
Efficiency of rehabilitation plan implementation	$\mathrm{E}\mathrm{I}\mathrm{R}\mathrm{P}={\displaystyle \frac{\mathrm{N}\mathrm{R}\mathrm{A}\mathrm{C}}{\mathrm{N}\mathrm{P}\mathrm{R}\mathrm{A}}}\times 100$	${\displaystyle \frac{6}{7}}\times 100\%=85.71$	${\displaystyle \frac{9}{10}}\times 100\%=90$
Quality of employees’ health	$\mathrm{Q}\mathrm{E}\mathrm{H}={\displaystyle \frac{\mathrm{T}\mathrm{N}\mathrm{S}\mathrm{W}}{\mathrm{T}\mathrm{N}\mathrm{A}\mathrm{W}}}\times 100$	${\displaystyle \frac{5}{30}}\times 100\%=16.67$	${\displaystyle \frac{3}{28}}\times 100\%=10.71$
Quality of land preparation for rehabilitation	$\mathrm{Q}\mathrm{L}\mathrm{P}\mathrm{R}={\displaystyle \frac{\mathrm{N}\mathrm{H}\mathrm{P}}{\mathrm{T}\mathrm{N}\mathrm{E}\mathrm{E}\mathrm{P}}}\times 100$	${\displaystyle \frac{3}{5}}\times 100\%=60$	${\displaystyle \frac{ 3}{4}}\times 100\%=75$

Where CEFRDL: coefficient of efficiency of use of funds for reclamation of disturbed lands. ARC: Actual restoration cost. PRC: Planned restoration costs. EERCR: Efficiency of environmental recovery costs for lands to be remediated. AECR: Actual environmental costs of remediation. TPBR: Total planned budget for rehabilitation. ECFRT: Efficiency coefficient of flora restoration on the territory subject to reclamation. TEFR: Total number of hectares of flora restored. TEAF: Total number of hectares of affected flora. ECFART: Efficiency coefficient of fauna restoration on the territory subject to reclamation. TNFSR: Total number of fauna species recovered. TNAFE: Total number of affected fauna species. EIRP: Effectiveness of the implementation of the rehabilitation plan. NRAC: Number of rehabilitation activities carried out. NPRA: Number of planned rehabilitation activities. QEH: Quality of employees’ health. TNSW: Total number of sick workers. TNAW: Total number of active workers. QLPR: Quality of land preparation for rehabilitation. NHP: Number of hectares prepared. TNEEP: Total number of hectares with erosion processes.

).

Based on the results obtained for the assessed indicators, a comparative study was conducted between 2018 and 2023 (see Figure 3).

The analysis of these results allowed us to consider the following:

• In 2023, the economic efficiency of the rehabilitation of the area to be reclaimed at the site of the abandoned Punta Gorda mine increased by 5.95%.
• In 2018, the environmental costs were estimated at 69.03% and in 2023 at 69.33%, indicating a slight improvement in environmental quality in the latter period.
• In 2023, the effectiveness of the restoration of flora and fauna species in the area to be rehabilitated, which were not assessed in 2018, was evaluated.
• In 2023, the effectiveness of the planned remediation measures improved, increasing by 4.29% compared to 2018.
• In 2023, the number of sick workers compared to 2018, indicating an improvement in the quality of health of workers affected by mining activity.
• Compared to 2018, in 2023, there was an improvement in the quality of land preparation for reclamation by 15%, which was reflected in the reduction of erosion processes.

3.11. Determination of the Economic, Social, and Environmental Benefits of Rehabilitation Management

As part of the assessment of the impact of the procedure used, the value of the ecosystem after rehabilitation was determined, as shown in

Table 8. Valuation of ecosystem goods and services after rehabilitation in 2023. Source: compiled by the authors.

Ecosystem Goods and Services	Economic Value (CUP)
Fauna	958.33
Wood m3	9390.72
Carbon dioxide	726,036.23
Water	7522.20
Total	743,907.48

.

The estimated benefits of the application of the socio-environmental and economic management procedure in rehabilitation of the 4 hectares developed at Punta Gorda are as follows:

Economics:

• The total economic value of goods and services of the studied ecosystem was determined at three points in time: before exploitation (4,345,093,175.26 CUP), after exploitation (7522.20 CUP), and after restoration (743,907.48 CUP).
• A quantitative assessment of the realization of the mine rehabilitation process was carried out using economic, social, and environmental indicators to measure the degree of ecosystem recovery.

Social:

• Covering the land with grass in inactive areas helped to reduce dust emissions into the atmosphere.
• Consumption of fruit from planted fruit trees contributed to the quality of life of the population and wildlife.
• Environmental culture was enhanced by educating workers involved in these activities and the residents of Punta Gorda on issues related to environmental protection.
• Knowledge and experience were transferred to workers who worked with experts and researchers on rehabilitation of the mining-affected area.

Environment:

• Ecosystem functioning has been restored, which will allow for future forestry and agricultural use.
• Proper land preparation in the reclaimed areas helped to reduce erosion processes and restore the soil in a shorter period of time.
• Nine species of fauna were found in the restored areas: Anolis porcatus (lizard); Osteopillus septentrionales (banana frog); Chordeiles gundlachii (turtle); and Calisto israeli (day butterfly).
• Flora recovery was achieved; the most representative species identified in the area are guava, maranion, pine, herbaceous plants, terrestrial orchids, and guao.

3.12. Drawing Up an Improvement Plan Based on the Results Obtained

During the monitoring carried out during the rehabilitation of the area, the presence of erosion processes on one hectare of land was identified as a deficiency in the process. Based on the analysis, two measures are proposed to address this deficiency: creation of a protective barrier of wood and stone and cleaning of filter dams.

4. Discussion

This study provides a comprehensive framework for the evaluation of the rehabilitation of the abandoned Punta Gorda mine, integrating economic, social, and environmental indicators. The applied procedure surpasses previous approaches by considering the multidimensionality of sustainable development in mining.

A comparative analysis reveals that while a significant body of prior research in Cuba has predominantly focused on environmental and ecological aspects, the present contribution serves to address this gap through the incorporation of economic and social dimensions. This holistic approach aligns with international standards for sustainable rehabilitation, which acknowledge the necessity of assessing economic impacts and social well-being to achieve effective recovery for both the ecosystem and the host community.

Nevertheless, the proposed methodology is not without its challenges and limitations. The quality and availability of localized data, particularly within the social and economic spheres, present a considerable constraint on the generalizability and depth of the analysis. The unique geographic and socioeconomic context of the Moa region introduces specific variables that complicate the direct application of universal indicators without significant contextual adaptation.

The findings are consistent with the principles and best practices for responsible mine rehabilitation advocated by leading international bodies. The procedure implemented at Punta Gorda underscores the critical importance of integrated and participatory management, the economic valuation of ecosystem goods and services, and the necessity of adaptation to local conditions. This suggests that the developed framework not only constitutes a contribution to the scientific advancement of the field within Cuba but also holds potential as a replicable model for other regions with comparable characteristics, thereby supporting broader regional and global strategies for sustainable mining.

5. Conclusions

• Sustainable development programs incorporate the Sustainable Development Goals into their objectives and aim to harmonize environmental, social, and economic aspects. International cooperation and mobilization of financial and technical resources are key to their effectiveness. Achieving sustainability requires the adoption of sustainable consumption and production patterns, the development of a circular economy, and environmental protection. Measuring the effectiveness of actions within this framework requires the use of integrated indicators and environmental and economic accounting systems. In addition, effective programs should involve local stakeholders, promote transparent and accountable governance, and have monitoring and evaluation mechanisms at the national and international levels.
• This study evaluated the effectiveness of implementing a sustainable development program for the rehabilitation of the abandoned Punta Gorda mine (Cuba) using an integrated system of socio-environmental and economic indicators. The main results demonstrate the practical significance of the research.
• The application of the proposed management procedure led to a 5.95% improvement in the economic efficiency of the rehabilitation work in 2023 compared to the reference year 2018. This demonstrates an optimization in the execution of the budget allocated to the recovery of land degraded by mining.
• The rehabilitation measures applied contributed to the partial recovery of the affected ecosystem. The total economic value of ecosystem goods and services, which fell sharply to 7522.20 CUP after mining, was restored to 743,907.48 CUP after rehabilitation. Efficiency in the restoration of flora was achieved at 72.73% and in fauna at 64.29%, with the reintroduction of nine species to the rehabilitated area.
• The quality of employee health improved, as reflected in the reduction in the number of sick workers, which suggests that a direct positive social impact was generated from the rehabilitation actions implemented.
• The quality of land preparation for rehabilitation improved by 15%, which resulted in greater control of erosion processes and higher quality soil conditions.
• In conclusion, the findings confirm that the methodological framework applied, based on the procedure developed by [44] constitutes a replicable model for sustainable rehabilitation of mines. This model demonstrates its practical usefulness by effectively balancing economic viability with environmental recovery and social well-being, directly contributing to the achievement of SDG 11 (Sustainable Cities and Communities). This study highlights the critical role of corporate social responsibility in mitigating the environmental impacts of mining and improving the quality of life of local communities.