Environmental Geochemistry Studies To Assess The Ecological Risks Of Gold Mining Activities In Egypt

1. INTRODUCTION

      Egypt contains several mineral sites and mines for a variety of minerals, including gold. The Eastern Desert houses about 90 gold mines that go back to ancient ages. Currently, the country is witnessing a revolution in the field of mining, especially gold mining activities.

     Our case study was take place at the Sukari Gold Mine (SGM) site, which is thought to be one of the largest mines in the Eastern Desert, with surveys and inquiries revealing a deposit of around 7.7 million ounces of gold in just one of the mine's portions. Mining and ore processing are also part of the plant. The Sukari Gold Mine is situated in the Eastern Desert's central region, about 22 kilometers southwest of Marsa Alam.

     Mining Operations and Activities Produced a wide variety of hazards that were not seen in other industries. Complex mining operations and processes may add certain hazards. If these risks are not adequately handled, employees may suffer severe injury, death, or occupational disease. (Castilhos et al., 2015; Jordan and Abdaal, 2013). Since ancient times, the eastern desert of Egypt has been recognized as a gold mining region, with more than 90 sites scattered around the whole area covered by Precambrian basement rocks. (Botros, 2002, 2004; El Ramly et al., 1970; Klemm and Klemm, 2013). The majority of these deposits were found and

     mined by ancient Egyptians (4000 B.C.) in many locations (Eisler, 2003; Helmy et al., 2004). Sukari Gold Mine (SGM) is now widely regarded as Egypt's first large-scale, modernized gold mine.

     SGM Activities contains Several Operations, Open Pit Mine, Underground Mine, Processing Plant, Gold Room and Power Plants in additions to other project services activities. All of these Operations and Activities may lead to produce some Hazards and Gasses emissions pollutants in the work Environments which can cause negative Impacts to the workers in some workplace locations.

     Apart from the protection and management concerns that arise while mining, the environmental issues that arise afterward cannot be overlooked. (Xiao et al. 2014a).

     One of the most critical issues facing SGM Management is minimizing and eliminating certain forms of hazards and impacts in the workplace in order to comply with Egyptian Environmental Protection Law EEL4/94 limits guidelines.

     Different mining operations, such as drilling, blasting, loading, hauling, crushing, and mineral processing, contain airborne particulate matter (Asif and Chen, 2016; Utembe et al., 2015). As a result, it is critical to implement the necessary control measures in order to reduce dust emissions and ensure that there are no dust emissions at workplace.

     Occupational health is used to identify and bring under control all chemical and physical hazards at the workplace. Risk assessment is the process of identifying hazards and evaluating the risks to health and safety arising from these hazards (Standard, 1996). The risk is the combination of the probability and consequences (harmful impacts) of a specified hazardous event. There are several studies used risk management to evaluate occupational health in the mining industry such as Charles et al., 2013, Hermanus 2007, Pan et al., 2010, Radosavljevic et al., 2009, Simonsen and Perry 1999, and Utembe et al., 2015. Part of our study aims (1) to evaluate the occupational health exposure to physical and chemical hazards in SGM workplaces, (2) to compare the levels of pollutants with the national and international guideline values, and (3) to apply risk assessment using a modified simple model. Our results will give the full recommendations and corrective actions required to eliminate the hazards in workplace to ensure safe work place for all workers and mine staff.

1. MATERIALS AND METHODS.

2.1.Study area

     Sukari Gold Mine (SGM) is situated in Egypt's Eastern Desert in the south-east, about 700 kilometers from Cairo and 25 kilometers from the Red Sea coast, and covers 160 square kilometers, as seen in )Fig. 1).SGM started producing in 2009, and by 2017 had increased production to 500 koz (103 ounces) each year. In 2015, the Sukari Processing Plant processed 10.6 million tons (Mt) of ore-rock, up 26% from 2014 (8.4 Mt), and produced 439 kilograms of gold, compared to 377 kilograms in 2014.The estimated number of employees has risen from 900 in 2011 to 1500 in 2019. Traditional open-pit and underground mining techniques are used to extract the deposit. The high-grade gold ore comes from underground operations, while the open-pit mine produces a considerable amount. The traditional crushing, grinding, and flotation methods are used to process the ore. Before being extracted as gold metal, precious metal from the concentrate is leached in a dilute cyanide

     According to clause 6.1.2 in ISO 14001:2015, Chemical Manufacturing Industry is required to conduct identifica­tion of environmental requirements Risk (aspects) from its operations according to (ISO 14001:2015), (Table 1 and Figure 1).

solution, absorbed into activated carbon, and removed from the carbon. (Oraby and Eksteen, 2016; Pratomo, 2014; Razanamahandry et al., 2016; Van Deventer and Van Der Merwe, 1994).

2.2.Identification of Potential Negative Impacts of Sukari site.

     The context and history data on the Sukari site enabled us to assess and recognize possible negative impacts in the workplace and the surrounding environment, as well as the effects of these negative impacts on Sukari employees and staff. From the construction phase to the operation phase. By examining mine operations and processing plant operations all negative impacts, hazards causes, and measurements needed to assess risk and hazards at work could be seen. This research looked at the effect of gold mining operations on air quality at the SGM Site. The sampling was done over the period of a year (2019 to 2020).

     Our occupational survey and monitoring will aid SGM management in making decisions to mitigate and remove all risks and hazards in the workplace in order to achieve environmental protection and keep employees and staff safe from any environmental harm.

2.3.Air Quality Monitoring and Measurements.

     SGM workplaces were subjected to environmental monitoring and measurements of noise, airborne particulate matter (PM10), and gas emissions. The measurements were carried out in 39 different locations as shown in (Fig.1) of Air Quality Monitoring Points, including working and ambient environments, offices, control rooms, and a workers' camp.

     Analyzed Air quality in workplaces was investigated by measuring meteorological data, noise level, dust emissions (PM10), and gases emissions. Measurements of harmful gases included CO, SO2, NO2, HCN, and NH3. Occupational Health and Safety, Environment training and monitoring programs are undertaken in SGM to develop and increase employee awareness of high HSE standards at Sukari site.

Figure 1: Study area and Air Quality Monitoring Points-SGM Site

2.4. Hazard Index and Risk assessment Models.

2.4.1.      Need for Risk Assessment

     Risk assessments will help the SGM operators to identify high, medium and low risk levels. Risk assessments will help to priorities risks and provide information on the probability of harm arising and severity of harm by understanding the hazard, combine assessments of probability and severity to produce an assessment of risk and it is used in the assessment of risk as an aid to decision making. In this way, SGM Managements and operators will be able to implement safety improvements. Different types of approaches for the safety in mines various tools and appropriate steps have to be taken to make mining workplace better and safer. A Hazard Identification and Risk analysis is a systematic way to identify and analyze hazards to determine their scope, impact and the vulnerability of the built environment to such hazards and its purpose is to ensure that there is a formal process for hazard identification, risk assessment and control to effectively manage hazards that may occur within the workplaces.

2.4.2.      Hazard Index(HI)

     Hazard Index (HI) is used to calculate the relative safety of exposure for mixtures of harmful substances. For substances that have similar toxicological effects such as harmful gases in the gold production projects, (HI) is estimated using (Formula1) (Wilkinson et al., 2000)

     Where n- is the number of substances measured in the same time at the same workplace. C1 is the concentration of substance 1 and TLV1 is its TLV-TWA, and so on for C2 and C3. If HI equal or increase than unity, the exposure of combined substances is greater than the limit even the individual concentration of these chemical substances are less than its TWA.

2.4.3.      Risk Assessment

     The risk Management was determined at work place by using qualitative method for the classification of risks (Table 1) and Risk Likelihood which show the evaluation of occupational health to avoid negative effects of workplaces on the employees. This risk analysis model Help us to setup the recommendations and the control measures required to eliminate the risk in the workplace. Moreover, it is used to evaluate

Table 2: Qualitative method for the classification of risks

 unavoidable risks to detect the risk at the source.

*Hazard Identification and Risk Analysis in Mining Industry 7bed5e49ad9568961ea003cae0e31028400d Risk Assessment.pdf

2.4.4.      Air Sampling and analytical methods.

     The research plan at the study area is succeed by using some high standards equipment and devices to do the measurements required for air quality monitoring in the work place for work and ambient environment. These equipment and devices already calibrated before the measurements and taken the samples to ensure the sampling of the measurements and the results very accurate and comply with the measurements standards.

1. RESULTS AND DISCUSSION

3.1.Assessment of air quality

     Our research and study target to assess the Air Quality at Sukari site in addition to Assessment the environmental pollution at Sukari Gold Mine to discuss the expected environmental hazards, Ecological Risks and the control measures required for safe workplace to achieve the environmental protection in the work place.

 Meteorology

     The meteorological data taken from the metrology station installed in Sukari site. The Temperature and Humidity data showing the weather condition at Sukari site and working area, from the Annual Temperatures and Humidity Data Values. The Temp. Values Recorded show The Highest Temp. Values (T Max. 48.1 0C) and the lowest Temp. (T Min. 3.4 0C) on the other hand the Humidity values recorded in the same period the Max. Humidity (H Max. 86.2) and the Min. Humidity (H Min. 3). Thus, The Sukari Hill locations consider as hot desert climate. So, the HSE department shall consider the heat stress Management during high temp. To ensure the work environment and workers are safe during summer period.

3.2.Noise Intensity Level (dB)

      Noise has become a major concern, especially in the mining industry. Most people who work in mining fields have suffered auditory and non-auditory harm as a result of exposure to high noise levels if they do not adhere to the workplace noise management policies. To avoid noise-induced hearing loss of staff, noise assessment and control measures are required. The SGM site is an outstanding example of how to manage noise levels in the workplace. Noise levels were measured in 39 different site locations of working and ambient environments as well as in Control rooms, Offices and camp area. The measured values range from 50.1 dB to 107 dB while the permissible noise level of working areas assigned by EEL4/94 is 90 dB for 8 working hours per day. According to this guideline value, there are Seven 7 workplaces have noise levels greater than the guideline. The greatest noise levels were found in the Power Generators House (107 dB), UG2 Area 2 -Tag board 770 (102.5 dB), Power station stacks Area (95.6 dB), Air Compressor Area (100.4 dB), At Mills (97.8 dB), UG Area 1-740 Access (91.4 dB), and Drill Pattern (91 dB), Control measures to reduce noise levels are considered in these sites by using the PPE and decrease the exposure limits. Noise levels were also measured within the Control rooms, Offices and camp areas and the results are presented and compared with the guideline value of EEL 4/94 (70 dB). Measurements carried out in all offices showed that the noise levels are lower than the allowable limit however, The power plant office noise level nearest to the limit (69.8 dB) it is recommended that the door of this office should be firmly closed at all times, check proper installation of rubber insulators on the door edges and double glasses is required to increase the isolation efficiency.

3.3.Dust Emissions - Particulate matters (PM10)

      It is well established that workers in high-dust environments, such as the mining industry, are more likely to develop respiratory diseases than workers in other sectors (Onder and Yigit, 2008). Measurements of respirable dust (PM10) were carried out in 39 locations working and ambient places. Results of airborne measurements are summarized as follow, The minimum value of the measured PM10 was detected at the new admin Office (0.08 mg/m3), while the maximum measured values was at 4 locations (4.6 mg/m3) at Underground Access No 740, (3.8 mg/m3) at UG2 Area 2 (Tag board 770), (3.6 mg/m3) at UG2 Area 3 and (4.2 mg/m3) Inside Laboratory(Sample Preparation room),According to EEL 4/94 for 8 working hours, all the other measured values are less than the permissible level (3 mg/m3) for 8 working hours. Except the above 4 locations. Reduction methods to PM10 have been applied to these sites such as water depression and firmly close the sources of airborne from the machines in addition to Wear the suitable PPE. For ambient environment the EEL 4/94 assigned 150 mg/m3 as a guideline value for PM10 for time exposure 24 hrs. The measured concentration is less than the permissible level. The source of the dust in these locations is the erosion of land by the wind not from mining activities as they located at least 1 km upwind of the mine. A curtain of trees is recommended to be planted in the upwind location of the camp and Main roads.

3.4.Gasses Emissions (CO, SO2, NO2, HCN, NH3)

     The different activities in SGM Operations produce several gases emissions in the work and ambient environment such as CO, SO2, NO2, NH3, and HCN. If Concentrations of these gases greater than their TLV or EEL4/94 limits may be Cause harmful effects to the workers on site.

     The concentrations of gases emissions were measured in 39 locations for different activities such as open-pit mine, underground mine, Process plant, and gold room. The measurements showed that gases emissions were not detected in some sites. In other workplaces, one or more gases were detected at the same time with different values of concentrations.

Results of gasses emissions measurements are presented in (Table 2). The maximum concentration of Carbon monoxide (CO) is found in Underground areas and CIL Tanks Area it is not increased than the EEL4/94 limits. SGM deposit is characterized as low Sulfur (SO2) and Nitrogen dioxides (NO2) where the detected level of it not increased than the EEL4/94 limits. The source of SO2 in SGM project is the liberations of sulfur from the host minerals of gold. Nitrogen dioxide (NO2) source release from power plant is less than its TLV-TWA in all detected locations.

3.5.  Hydrogen Cyanide (HCN)

      is a Toxic gas, which produced during gold cyanidation (Donoghue, 2004; Yannopoulos, 1991). Occupational exposure to HCN is detected in Carbon in leaching tanks (CIL TANKS 1&2) with concentrations (5.5 ppm) and (5.4 ppm) respectively and in Underground areas HCN was detected (7 PPM) at UG Area1(740 Access), (6 PPM) at UG2 Area 2 (Tag board 770) and  (5 PPM) at  UG Area (3). The values of HCN are Consider high compared with its limits assigned by EEL 4/94. So, Workers at Underground and CIL Tanks Locations should always have Dose meter equipment with Alarm to detect HCN high concentration, wear a gas mask when the concentration exceeds 10 ppm, and evacuate the area when the level exceeds than 20 ppm.

3.6.Ammonia (NH3)

      was detected in some workplaces at different mining activities. Significant values were found in Underground, Gold Room and CIL Tanks areas with different values. The other locations have lower concentrations and all measured levels are lower than ammonia TWA limits (25 ppm).

Hazard Index (HI) and Risk Assessment Rating Model.

      Combined exposures to multiple Gasses emissions, or mixtures, require special consideration in evaluating the occupational health hazard. Hazard Index (HI) is used to calculate the relative safety of exposure for mixtures of harmful substances. For substances that have similar

Toxicological effects such as harmful gasses in the gold production projects, Hazard Index (HI) is estimated using (Formula 1) (Wilkinson et al., 2000) and the results are given in (Table 2).

     Where n- is the number of substances measured in the same time at the same workplace. C1 is the concentration of substance 1 and TLV1 is its TLV-TWA, and so on for C2 and C3.

     If (HI) equal or increase than unity, the exposure of combined substances is greater than the limit even the individual concentration of these chemical or gasses emissions are less than its TWA. In the investigated areas, several sites at where more than one gasses emissions was detected in the same time and consider high risk areas  such as Underground areas At these locations, three gasses emissions were measured in     addition to PM10. No individual gas increased than its TLV-TWA, while the estimated value of (HI) is more than (1), which shows that the occupational hazard in these locations is greater than the permissible limit for combined exposure. (HI) greater than unity was found also in other three locations in the workplaces. Flotation Tanks and CIL Tanks 1&2. In working environments with HI > 1, control programs have to be implemented to reduce the concentrations of the gasses emissions to the EL limits.

      So, in addition to (HI) applied the risk assessment (Quantitative method Table 1) to calculate the risk rating for occupational health. A case study of the modified risk assessment model is implemented for the workplace in SGM as shown in (Table 2). And the results are recorded in the last column of (Table 2). In this table, 27 workplaces have Low Risk, 1 workplace has Medium Risk and 11 workplaces have High Risk.

      Also, we can note some of workplace has High Risk, has also Hazard Index (HI) more than unity, and the site of medium Risk have Hazard Index (HI) values more than half. Despite (HI) determines if a workplace has an occupational hazard on worker's health or not, it doesn't explain which Gasses emissions contribute this hazard. While the risk assessment model gives an adequate explanation about the source/s of such hazards. Therefore, The High and Medium risk locations shall be classified as the most risk and Hazards areas in the work place and all workers will be work at these locations must wear the required PPE during work time at these locations as shown in the high / medium risk locations in (Table 3) below.

Also, we can note some of workplace has High Risk, has also Hazard Index (HI) more than unity, and the site of medium Risk have Hazard Index (HI) values more than half. Despite (HI) determines if a workplace has an occupational hazard on worker's health or not, it doesn't explain which Gasses emissions contribute this hazard. While the risk assessment model gives an adequate explanation about the source/s of such hazards. Therefore, The High and Medium risk locations shall be classified as the most risk and Hazards areas in the work place and all workers will be work at these locations must wear the required PPE during work time at these locations as shown in the high / medium risk locations in (Table 3) below.

*Hazard Identification and Risk Analysis in Mining Industry 7bed5e49ad9568961ea003cae0e31028400d Risk Assessment.pdf

1. CONCLUSION

     Defining and analyzing hazards is the first step in assessing Ecological risks and maintaining a safe workplace. Although all hazards should be addressed, resource constraints usually prevent this from happening all at once. Environmental measurements, hazard analysis, and risk assessment should all be used to determine targets such that the most risky conditions are dealt with first, followed by those that are less likely to occur and cause significant problems.

      The analysis conducted at the SGM Site, as well as the hazard index and risk rating that were created and evaluated, revealed that there are a variety of high risks in the workplace due to a lack of control measures that must be implemented in a proper manner and under oversight to ensure a safe workplace.

     Owing to some of the usual procedures that produce a lot of noise, improper use of personal protective equipment should be controlled to reduce risk and exposure at high risk locations.

      Since dust emissions (PM10) can harm people in an accident, roads in mining areas, especially underground locations, must be carefully and uniformly spaced for safe and comfortable machine movement, as well as proper traffic signals and boards installed over a certain distance.

      The environmental measurements taken for some gasses emissions, such as CO, SO2, NO2, HCN, and HN3, at work in various site locations reveal high-risk workplace environment, with only hydrogen cyanide concentrations above the allowable limit in some workplaces. In these workplaces, continuous detection of HCN levels is needed to prevent immediate harmful effects on workers' health, as well as the installation of a dose meter warning detector for all workers employed at high HCN locations.

The updated risk assessment model's performance was compared to the Hazard Index's expected value (HI). They both came up with the same outcome, proving the high risk rating at work.

Acknowledgement

      The authors gratefully thank SGM Management for their help; facilitate the visiting of Sukari Gold Mine, and implementing the required measurements in the workplaces. Also, the authors thanks Department Evaluation of  Natural Resources, Environmental Studies and Research Institute, University of Sadat City for their help to successes the study. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.