*Article* **A Conceptual Framework to Evaluate the Environmental Sustainability Performance of Mining Industrial Facilities**

#### **Komninos Angelakoglou \* and Georgios Gaidajis**

Laboratory of Environmental Management and Industrial Ecology, Department of Production Engineering and Management, School of Engineering, Democritus University of Thrace, 67100 Xanthi, Greece; geogai@pme.duth.gr

**\*** Correspondence: kangelak@pme.duth.gr; Tel.: +30-25410-79356

Received: 22 February 2020; Accepted: 6 March 2020; Published: 10 March 2020

**Abstract:** The aim of this study is to strengthen the capacity of mining industries to assess and improve their environmental sustainability performance through the introduction of a relevant framework. Specific assessment categories and respective indicators were selected according to predefined steps. Sustainability threshold values were identified for each indicator to enable the comparison of the facility's performance with a sustainability reference value. The application of the framework results in the extraction of an Environmental Sustainability Assessment of Mining Industries Index (IESAMI). The framework was applied to evaluate a mining facility in Greece, with a view to improve its applicability in parallel. The final score of environmental sustainability for the examined facility was 3.0 points (IESAMI = 3.0 points), indicating significant room for improvement where the company should aim to further enhance its sustainability performance.

**Keywords:** sustainability assessment; index; sustainable mining; threshold values; sustainability indicators

#### **1. Introduction**

Business and industrial activity are being reformed to cope with the needs and challenges of sustainable development. Environmental responsibility is moving beyond being just a legal obligation—it also stands out as a good business practice through the expansion of markets and the improvement of sales [1]. Managers face the challenge to deliver better corporate sustainability strategies [2], whereas external agents are increasingly paying attention on the concept of sustainable development [3]. While the reasoning behind the need of companies to contribute to sustainable development has been extensively analyzed in literature, relatively less progress has been made in developing integrated approaches for sustainability evaluations [4]. As a result, during the last few years, a significant number of studies attempted to strengthen sustainability evaluations at the corporate level by providing both generic and specific recommendations and guidelines [5–8].

This field of research is especially critical for mining industries which are inherently disruptive to the environment. The interdependence of mining activity and sustainable development is reflected on relevant initiatives (such as the Global Mining Initiative, Towards Sustainable Mining commitment of the Mining Association of Canada, the Sustainable Mining Initiative by Federation of Indian Mineral Industries, etc.) that attempt to set a common framework to promote responsible mining. In parallel, there is a growing interest among the academic community regarding issues associated with mining and sustainable development [9]. Mining industries usually exhibit commitment to the environment through the adoption of environmentally responsible practices [10] and sustainability reporting, with a view to balance negative impacts and reduce opposition by local communities [11]. Corporate sustainability reporting, especially through the adoption of the Global Reporting Initiative (GRI) guidelines, is now considered a common practice for measuring, reporting, and comparing sustainability performance [12].

Despite this background, there are many criticisms regarding the relationship between mining activity and environmental sustainability, and the literature argues that there is still significant room for improvement. Although social and environmental reporting is becoming increasingly sophisticated in the mining industry, there is a lack of uniformity that hinders the progress toward measuring corporate social responsibility and sustainable goals [13]. Belkhir et al. [14] assessed whether the GRI impacts environmental sustainability in terms of CO2 emissions and found no correlation between GRI-reporting and sustainability improvement, a result that calls for the re-examination of the effectiveness of corporate social responsibility strategies. Another issue that has been raised in the literature is the ability to compare the sustainability performance of firms, even from the same sector, which remains problematic [12]. The mining corporations' framework for measuring and reporting sustainability progress needs to be changed in order to reflect more accurate and meaningful information [15]. Tost et al. [16] argue that the mining industry is at risk of failing societal expectations regarding climate change and falling behind from other industries on natural capital considerations.

According to Lopez et al. [6], research on corporate sustainability performance need to focus on the standardization of measurements, whereas stakeholders should apply indicators measured at wider scales. It is necessary to develop and implement effective tools and methodologies to support decision making, taking into account the complexity of sustainability problems [17]. One of the biggest challenges at the moment is closing the gap between theory and practice. Despite the fact that many researchers have been working on developing sustainability assessment methods and tools, relatively few of these are applied by manufacturing companies [18].

Serving this challenge, the aim of the specific study is to provide a practical framework that is able to strengthen the evaluation and monitoring of the environmental sustainability of mining industrial facilities. The proposed framework capitalizes the results and proposals of an extensive literature review we have conducted in a previous work [19]. In this work, 48 methods were identified and clustered into six categories (individual/set of indicators, composite indices, socially responsible investment indices, material and energy flow analysis, life cycle analysis, and environmental accounting), extracting in parallel their key attributes. These categories were further evaluated based on five criteria—(a) ability to promote actions of improvement, (b) ability to help decision making, (c) potential for benchmarking, (d) applicability and ease of use, and (e) integration of wider spatial and temporal characteristics. This analysis highlighted key recommendations that can help improve the efficiency and applicability of environmental sustainability evaluations of industrial systems. More specifically, we found out that an industrial facility should be assessed both in terms of performance and concern and provide environmental sustainability threshold values for every indicator applied. An effective environmental sustainability assessment method should take into account the spatial characteristics of the examined industrial systems and assess the progress towards sustainability over time.

This paper consolidates key findings from our previous work [20–26] (i.e., proposed environmental sustainability assessment categories—building upon the principles of industrial ecology, criteria for selecting indicators to assess industrial facilities, a proposed normalization method combining categorical scale and distance to a reference), but takes one big step further by integrating all information into an applicable framework that focuses on mining industry and that was tested in a mining facility in Greece to examine its utility (closing the gap between theory and practice).

#### **2. Method**

The proposed framework was developed building upon a standard methodology for constructing composite indicators. A theory-driven (top-down) over data-driven (bottom-up) approach was adopted to ensure that environmental sustainability will be efficiently assessed through the selection of proper indicators. The methodology applied consists of 10 steps (Figure 1) that were defined by taking into account available guidelines for the construction and use of composite indicators [27] and the recommendations from the analysis of 48 sustainability assessment methods as described above [19].

**Figure 1.** Methodology followed to construct the proposed assessment framework.

The 10 steps are divided into two stages of implementation in order to accommodate the gradual application of the proposed framework. The first stage comprises steps 1–5 and includes the minimum actions to be conducted by a mining industry on a facility level, who wish to acquire an initial overview of its performance related to environmental sustainability aspects. This stage is addressed to industries that have little time and resources at their disposal. The implementation of the first stage provides the data required for the assessment of the environmental sustainability. The second stage comprises the steps 6–10 and includes all actions required for the effective assessment of the environmental sustainability of the facility. The implementation of the second stage results in the development of a final comprehensive environmental score and the identification of environmental "hot spots" that call for improvement.

In the following sections, the 10 steps comprising the conceptual framework are presented. Each step contains both generic implementation guidelines and more specific instructions. Generic implementation guidelines can be used to improve existing assessment methods applied by industries, whereas specific instructions provide all the information necessary for the direct assessment of environmental sustainability. As a result, the utility of the proposed framework is twofold. It can act both as a path to develop new assessment methods (or improve existing ones) and as a ready to be used tool.

#### *2.1. Definition of the Objective and Scope of the Assessment*

The first step taken in order to develop the framework was to define the objective of the assessment. Indicative objectives include the identification of weaknesses and the development of improvement measures, comparison with other industrial facilities, monitoring the performance of industrial facility over time, and enhancing sustainability reports. Additionally it is necessary to define the scope of the assessment. The reference year and the boundaries of the industrial facility under examination must be selected in order to serve the objectives of the assessment. Significant factors to consider among others are the availability of data, the budget and time available to perform the assessment. The identification of the target groups to whom the results of the assessment will be addressed can further increase the effectiveness of the framework. Ecological organizations, local residents, and control bodies favor methods that follow more eco-centric approaches.

The objective of the proposed framework is to enable the evaluation and monitoring of the environmental sustainability performance of the examined facility, thus strengthening corporate decision making on a higher level. This choice is based on the fact that key strategic decisions on sustainability-related issues are mostly taken on an upper-management level. The full implementation of the proposed framework is addressed primarily to mining industrial facilities that are already in operation. The scope of the assessment includes the whole supply chain from raw material extraction to final processing (cradle to gate approach). This approach is essential to capture environmental impacts deriving from different life cycle stages of the operation of the examined facility. The time reference for the assessment is one year (annual implementation/results) to serve compatibility with annual reports and facilitate data mining.

The reason for conducting the assessment on the industrial facility level (rather than corporate level) is that it enables the identification of unsustainable industrial processes/practices at the source while taking into account specific spatial characteristics of the facility under examination. Consequently, the results of the assessment are expected to better facilitate decision making and the identification of amelioration actions. The proposed methodology is focusing at the moment only on the environmental aspect of sustainability but can be adapted to include economical and social aspects.

#### *2.2. Definition of Assessment Categories*

The next step was to identify various sub-categories that compose the examined phenomenon, which in our case is environmental sustainability [27]. In other words, the parameters need to be considered for efficiently assessing the environmental sustainability of the system under examination had to be identified. Sustainability assessments should be based on certain principles to enhance their effectiveness [28]. Additionally, every sub-category must have a clear purpose that serves the goal of the evaluation. To ensure that the most important issues in terms of environmental sustainability will be assessed, the principles of industrial ecology (IE) were utilized to develop the specific framework. The authors have summarized and examined the principles of IE in a previous work [21]. Additionally, the environmental assessment categories proposed by the Global Reporting Initiative [15] and further recommendations by mining experts were taken into account. As a result of this process, a list of eight key categories to assess the environmental sustainability was developed (Table 1).


**Table 1.** Proposed environmental sustainability assessment categories.

## *2.3. Development of an Indicator Pool*

Following the definition of assessment categories, an indicator pool was developed including indicators that can potentially be utilized to assess the eight environmental sustainability categories. A filtering procedure according to predefined criteria was undertaken to narrow down the vast number of potential indicators that can be included in the pool [29]. Two screening criteria were selected by the authors in order to identify potential indicators that can be utilized in the proposed framework—(a) the indicator must be included in at least one of the available environmental sustainability methods reviewed [19] and (b) the indicator must satisfy the principles of IE to ensure that sustainable actions highlighted by IE will be promoted [22]. According to that criteria set, we developed a list of 108 indicators. Indicators with similar name or common indicators expressed in different units appear once in the list so the actual number of indicators analyzed is much higher.

#### *2.4. Selection of Key Indicators and Allocation to Categories*

The final key indicators to be integrated into the framework were selected from the pool with the application of five criteria [26]—(a) be easily understandable to various stakeholders, (b) be easily measured and are cost-effective in terms of data collection, (c) can cover long-term issues and be applied in multiple scales, (d) support decision making and promote desired behavior, and (e) be potentially comparable. All indicators included in the indicator pool (Step 3) were ranked according to these criteria with the utilization of a 0–4 scoring scale per criterion, resulting in a final score from 0–20 points per indicator (where 20 indicates maximum performance). The indicators were scored by a panel of five experts from both academia and industry. The analytical process followed to select the final core indicators is the following:


Resulting from this process, 19 final core indicators of environmental sustainability were selected that constitute the basis of the proposed framework (Table 2). The fact that the indicators were selected according to a structured and clear process increases the efficiency of the evaluation and ensures that most important parameters in terms of environmental sustainability are measured without increasing too much the time and resources required for the implementation. However, additional case specific indicators may be integrated by the user, if deemed necessary.

#### *2.5. Quantification of Indicators and Initial Analysis*

During this step, the evaluator must collect all data needed for the efficient quantification of the indicators and perform an initial analysis of the results. The initial analysis should include a validity check in order to examine whether the indicator values are reasonable and identify any errors in data collection [24]. If data are available from previous years, comparing the results and trying to justify differences is encouraged. In Section 3, the framework was implemented in a mining facility in order to examine its applicability and usefulness.

#### *2.6. Normalization and Evaluation of Indicators*

Normalization of indicators is necessary if we want to proceed to data aggregation [30]. Indicators above or below the mean, min-max, z-score, distance to a reference, and categorical scales are some examples of the normalization methods available [27]. A sensitivity analysis of normalization methods indicated that the distance to a reference method is the most suitable choice for sustainability performance evaluations in industry [30]. Based on this finding, we propose a hybrid normalization procedure, combining the categorical scale and the distance to a reference approaches. Distance to a reference is applied to compare the value of an indicator to a reference value whereas categorical scale assigns a score to every indicator using a numerical or qualitative scale. The same approach has been successfully applied to normalize and assess key indicators utilized for the evaluation of sustainable water consumption and management of industrial facilities [26].



The reference value serves as the starting criterion to assign sustainability scores with the application of a 5-point semi-qualitative scale (Very High (5), High (4), Medium (3), Low {2), and Very Low (1)). Specific sustainability reference values were identified for each indicator to enable the comparison of the examined industry's performance with a sustainability reference point (see Appendix A). In our case, sustainability reference values reflect (a) either target values set by EU or international organizations, (b) either values derived from the analysis of the performance of international mining projects, (c) either expert's estimations and proposals from international scientific literature, or (d) either corporate objectives.

The pros and cons of the proposed normalization procedure were summarized and are presented in Table 3. The identification of commonly accepted reference values for every indicator was found to be a time and effort intensive process especially for uncommon indicators. To cope with this challenge, internal targets and expert judgments can be applied until a more concrete reference value is available. These targets must be evaluated and modified regularly to reduce subjectivity. The basic goal of the specific procedure is to aggregate indicators into one single sub-index. Loss of information during normalization can be balanced if the initial analysis (Step 5) has been carefully conducted [24].


**Table 3.** Pros and cons of the proposed normalization method [23].

#### *2.7. Weighting*

Weighting (expression of how important is a parameter compared to another) is a particularly significant step during the development of a composite indicator [31]. As in the case of a normalization process, there is not a commonly accepted way of data weighting [32]. Weights selected by the analyst is not necessarily a bad practice; however, it is very likely to have negative consequences regarding the acceptance of the results [33]. On the other hand, weights result from statistical methods, may be even less acceptable from the perspective of decision-making and policy development toward sustainability, as insignificant political parameters can receive high scores, while innovative approaches on sustainable development may not even taken into consideration [32].

In the proposed framework, we suggest equal weights to be attributed to all indicators and assessment categories. The specific decision is based on two basic reasons. The indicators of the framework were selected using a concrete procedure to ensure that key environmental issues are examined with maximum efficiency. Every indicator serves a different aspect of environmental sustainability, and all issues must be taken into account if we want to move towards sustainable development. Equal weights discourage industries from merely focusing on the improvement of the indicators with the higher weights. This approach serves better the sustainability notion according to which the performance of a system should be assessed taking into account various parameters (holistic approach). Second, it should be taken into account that the proposed framework attempts to assess industrial facilities regardless their special characteristics (e.g., size). If weights were to be adopted, these would have to be adapted to specific types, sizes, and spatial characteristics of the facility, which would significantly increase the complexity and uncertainty of the results, especially if used for benchmarking purposes.

#### *2.8. Aggregation*

The utilization of a high number of indicators might be problematic for the efficient communication of the environmental sustainability to the senior management of the industry and the general public. Since all indicators are expressed in a common quantitative scale (1–5 points), the extraction of individual sub-indices, and a final single index of environmental sustainability is possible. More specifically, by applying the proposed framework, the following environmental sustainability scores can be extracted:

• Per assessment category—Eight sub-indices:

	- -IESAMI: Environmental Sustainability Assessment of Mining Industries index

The sub-indices per assessment category result from the average score of the indicators that compose the category:

$$\mathbf{I}\_{\mathbf{X}} = \frac{\sum\_{i=1}^{n} w\_i}{n},\tag{1}$$

where x is the examined category (*<sup>x</sup>* <sup>∈</sup> <sup>Z</sup>{1, ... , 8}), wi is the score of the indicator i, and n is the number of indicators included in the assessment category x. Sub-indices Ix can help industries identify and analyze those categories where there is a great potential for improving their environmental sustainability. The final index of environmental sustainability is estimated from the average score of the eight assessment categories:

$$\mathbf{I}\_{\text{ESAMI}} = \frac{\sum I\_{\text{X}}}{8} \text{ where } \mathbf{x} \in \mathbb{Z}\{1, \dots, 8\}\,. \tag{12}$$

The extraction of a final overall score enables the efficient communication of the results and comparison with other facilities provides an overview of the environmental sustainability of the examined facility and allows the regular re-evaluation of the progress achieved through the years.

#### *2.9. Presentation of the Results*

The presentation of the results is an issue that should not be neglected and depends on many factors such as the target audience [34]. The proposed framework provides significant feedback (indicators utilization, extraction of sub-indices, finding reference values, quantitative scores, etc.) for the efficient presentation of the results. A number of key techniques for enhancing the presentation of the results include: the development of summarized tables of results, the development of trend charts per indicator for consecutive years, the development of graphs depicting the scores per sub-indices, the presentation of key results to websites, leaflets, and others. The results from the implementation of the framework could serve as an important means of strengthening sustainability reports, corporate social responsibility reports, environmental impact studies, and relevant presentations at meetings and conferences.

#### *2.10. Analysis of theRresults and Regular Re-Assessment*

The final step refers to the analysis and interpretation of the results. The analysis of the results is the step with the highest impact on the facility under examination since their interpretation will lead to successful decision making and the formulation of strategies for improving environmental sustainability. Consequently it should be performed with great attention. A successful analysis of results should be able to answer the following key questions:

Analysis per assessment category: Which categories present the lowest score and what factors (indicators) caused this? In this case it is particular useful to return to the results of step 5 in order to explore in greater depths the indicators that received the lowest scores.

Total analysis: What is the final score of environmental sustainability and how it can be improved? The conduction of a sensitivity analysis to quantify the alternative actions of improvement is highly encouraged at this stage. For the easier analysis of the results, the following general rule of interpretation is proposed depending on the rating of the index:


As already mentioned, the utility of the proposed framework is twofold. It can act both as a path to develop new assessment methods (or improve existing ones) and as a ready to be used tool by industries who wish to assess their environmental sustainability. In the second case, the user can utilize the analytical results of the implementation of each step described before (proposed assessment categories, indicator pool, implementation guide, core indicators etc.). In this way, industries only need to apply steps 1, 5, 6, 8, 9, and 10, which reduces the time and cost of implementation.

## **3. Case Study—Evaluation of a Mining Facility in Greece**

The proposed framework was implemented in a mining industrial facility in Greece in order to examine its applicability and usefulness. The system under examination was selected with a view to represent facilities of relatively high complexity of material and energy balances and significant environmental concerns. The steps described in the previous section were applied by taking into account the following assumptions.

The objective defined was to assess the overall environmental sustainability performance (current state of operation) and identify key weak spots that call for improvement. The scope of the assessment included the entire mining and metallurgical installations of the mines in the area that were examined as an entity to reflect the overall sustainability performance of the mining activity of the company.

The environmental sustainability performance was assessed using the eight proposed thematic categories and the 19 core environmental sustainability indicators of the framework. Indicators EN3, EN4, and EN19 were not evaluated due to the lack of relevant data because the facility was in the process of developing the necessary procedures for their quantification during the conduction of this study.

The data required for the assessment of each indicator were acquired from the following sources: a) published sustainability reports of the company, b) published data from the Association of Mining Enterprises in Greece, c) raw data from the environmental monitoring program of the company, and d) published data from technical reports and Environmental Impact Assessment studies. The normalization and evaluation of the indicators was carried out using the proposed method and respective sustainability reference values presented in Appendix A. It was further decided that all indicators and categories are of the same significance (no weights were attributed). Specific data and calculations will not be presented in detail due to confidentiality reasons and space restrictions. For a better understanding of the results though, a number of particular features of the case study are clarified below that have significantly influenced the evaluation.

A number of sites within the facility were still under development and/or at the stage of preparing the start of production, resulting in the consumption of high quantities of raw materials, energy, and water without the corresponding production of marketable products. That led to an abnormal correlation between the quantity of run of mine (ROM) ore and the marketable products with the inputs (raw materials, energy, water) and outputs (gaseous emissions, liquid waste, solid waste). As a result, indicators assessed in relative units (per ton of ROM ore) exhibited low or very low performance even when there has been an annual reduction in absolute terms. Typical examples are the indicators EN5, EN6, and EN15 related to the deposition of mining waste, energy consumption and global

warming potential respectively. The production process is expected to be normalized during the full development of the examined facility, and thus, the assessment will better capture the efforts of the company to improve its sustainability performance.

## *3.1. Results PerIindicator and Assessment Category*

The results per indicator and per assessment category are summarized in Table 4 and Figure 2 respectively. The score of the assessment categories ranged from 1.0 (I2—missions and waste) to 5.0 points (I8—human health impacts) exhibiting a noticeable fluctuation per indicator and category. The case study received the highest score in 6 out of 16 indicators evaluated (indicators 2, 8, 11, 13, 16, and 18) and the minimum score to 6 (indicators 1, 5, 6, 7, 12, and 15). The peculiarities of the year of examination, discussed in the previous section, do not allow the extraction of safe conclusions for the assessment categories I1, I2, and I3. It is characteristic that for the specific year, the mass balance of inputs and outputs was negative while the output intensity (tons of outputs produced per ton of ROM ore mined) was higher than that input intensity (tons of inputs consumed per ton of ROM ore mined).


**Table 4.** Environmental sustainability performance per indicator.

**Figure 2.** Environmental sustainability performance per category.

The examined facility is characterized by very high rates of recovery/reuse of mining waste (EN2 = 5.0 points) and water (EN8 = 5.0 points), thus balancing the negative impact of development and restoration works during this stage. The facility management has undertaken a significant number of initiatives to enhance its environmental performance, accountability and equity, whereas takes into account the environmental performance of its contractors (I4 = 4.0 points), supporting the view that industries with particular environmental concerns and pressures, tend to account more on environmental management related issues.

The facility is characterized by moderate performance regarding biodiversity protection (I5 = 3.0 points). The high concern due to the significant biodiversity of the area (EN12 = 1.0 points) is offset by mitigation actions on biodiversity (EN13 = 5.0 points) as the company has taken a significant number of relevant initiatives in line with best available practices for biodiversity protection. At this stage (development of sub-projects), the case study is characterized by low performance in land use and rehabilitation (I6 = 2.0 points) as the majority of the disturbed area has not been restored. The score in the specific category is expected to improve over time as rehabilitation works are in progress.

The assessment categories related to environmental and climate change impacts (I7 = 3.3 points) and human health impacts (I8 = 5.0 points) exhibited moderate and very high performance respectively. This result indicates that the operation of the facility affects the environment and human health in an acceptable way, in case an environmental accident does not occur. An exception is indicator EN15 regarding global warming potential, which received a minimum score as the equivalent carbon dioxide emissions are calculated on the basis of the energy consumption per ton of ROM ore. Carbon dioxide emissions in absolute units (≈57,000 tons) are at normal levels for heavy industries and much lower that energy and chemical industries. Reagents utilized in the production process, although mostly

hazardous, represent a very small proportion of the overall input–output balance and with proper management the risk of large-scale accidents is minimized. On the contrary, the produced products and materials left over after the separation process present a significant risk due to the combination of their quantities and risk.
