Environmental Regulatory Processes relating to the amendment of the Environmental Management Programme for its Elandsfontein Operations Soils, Land Use and Land Capability Impact Assessment Project Number: Prepared for: Elandsfontein Colliery (Pty) Ltd August 2017 Digby Wells and Associates (South Africa) (Pty) Ltd Co. Reg. No. 2010/008577/07. Turnberry Office Park, 48 Grosvenor Road, Bryanston, 2191. Private Bag X10046, Randburg, 2125, South Africa Tel: +27 11 789 9495, Fax: +27 11 069 6801, info@digbywells.com, www.digbywells.com Directors: GE Trusler (C.E.O), GB Beringer, LF Koeslag, J Leaver (Chairman)*, NA Mehlomakulu*, MJ Morifi*, DJ Otto, RA Williams* *Non-Executive
This document has been prepared by Digby Wells Environmental. Report Type: Project Name: Project Code: Soils, Land Use and Land Capability Impact Assessment Environmental Regulatory Processes relating to the amendment of the Environmental Management Programme for its Elandsfontein Operations Name Responsibility Signature Date Siphamandla Madikizela Report Compiler January 2017 Brett Coutts Report Reviewer January 2017 This report is provided solely for the purposes set out in it and may not, in whole or in part, be used for any other purpose without Digby Wells Environmental prior written consent. Digby Wells Environmental i
DECLARATION OF INDEPENDENCE Digby Wells and Associates (South Africa) (Pty) Ltd Contact person: Siphamandla Madikizela Digby Wells House Turnberry Office Park 48 Grosvenor Road Bryanston Tel: 011 789 9495 Fax: 011 789 9498 E-mail: siphamandla.madikizela@digbywells.com 2191 I, Siphamandla Madikizela as duly authorised representative of Digby Wells and Associates (South Africa) (Pty) Ltd., hereby confirm my independence (as well as that of Digby Wells and Associates (South Africa) (Pty) Ltd.) and declare that neither I nor Digby Wells and Associates (South Africa) (Pty) Ltd. have any interest, be it business, financial, personal or other, in any proposed activity, application or appeal in respect of Anker Coal and Mineral Holdings South Africa (Pty) Ltd, other than fair remuneration for work performed, specifically in connection with the proposed update of Elandsfontein Colliery EMP near Secunda, Mpumalanga. Full name: Title/ Position: Qualification(s): Siphamandla Madikizela Soil Scientist MSc in Soil Science Experience (years): 3 Registration(s): SACNASP (Cand. Nat. Sci:100033/13) Digby Wells Environmental ii
EXECUTIVE SUMMARY Digby Wells Environmental (hereafter Digby Wells) was requested by Anker Coal and Mineral Holdings South Africa (Pty) Ltd to update the Environmental Management Programme (EMP) for Elandsfontein Colliery. The aim of this Soil Impact Assessment was to provide an update and accurate record of the soil resources of the Elandsfontein Colliery Environmental Management Programme (EMP). The following tasks were undertaken in the compilation of the soil, land use and land capability assessment: Review of the existing soils information conducted by Digby Wells and AV Environmental Management Services cc; Update land capability and land use maps; Update the impact assessment with associated current activities; and Update the soils, land capability and land use report. As part of the desktop assessment and field assessment that was conducted on the 7 th and 8 th November 2016, baseline soil information was obtained from South African land type data published with maps at a scale of 1:250 000 by the Institute for Soil, Climate and Water (ISCW) of the Agricultural Research Council (ARC). The land type data indicated that the main land types were Ba5 and Bb13. The study site is dominated by Hutton, Avalon, Longlands and Mispah soil forms. The land capability consists of predominately Class II (Intensive cultivation) and Class III (Moderate cultivation). The dominant land uses within the area are mining activities and grazing land covered by grassland. The major impact on soil resources associated with open pit mining occurs through destruction of the soil profile. Soil layers are stripped and stockpiled for later use in rehabilitation. During this process there can be a loss of topsoil through erosion and dilution of topsoil through mixing with deeper soil horizons. Compaction and loss of soil structure commonly also occur as well as a loss of biological activity if topsoil is deeply stockpiled for long periods. Thus, the rehabilitated land is typically less suitable for agriculture than it was before mining. The following actions are recommended to minimise the impact of mining on the soils, land use and capability: Soil should be stripped during dry months, if possible (May to October), adhering to clearly defined guidelines for stripping, with topsoil being saved separately to permit, after mining, reconstruction of the soil profile into one resembling that which was removed; The soil stockpile should have a maximum height of 4 m to minimise adverse effects on soil chemical and physical properties; Hydrocarbon pollution must be cleaned up by emergency clean-up kits; Digby Wells Environmental iii
Opencast excavations must be backfilled and then covered with subsoil first and then topsoil; Soils need to be managed properly to reduce the impacts and soil stockpiles must be only be used for rehabilitating; Soil fertility should be assessed and restored by means of sampling and chemical analysis, before mining and after rehabilitation; and Water runoff must be controlled and managed by means of proper storm water management facilities. Digby Wells Environmental iv
TABLE OF CONTENTS 1 Introduction... 1 1.1 Background... 1 1.2 Project Activities... 1 2 Terms of Reference... 2 3 Aims and Objectives... 2 4 Details of the Authors... 2 5 Environmental Law Applicable to Study... 3 6 Methodology... 3 6.1 Desktop Assessment... 3 6.2 Site Assessment... 3 6.3 Land Capability... 4 6.4 Land Use... 5 7 Existing Information... 5 7.1 Soils... 5 7.2 Soil Fertility... 5 7.3 Rehabilitated Areas... 6 8 Current Assessment Findings... 7 8.1 Land Type Data and Soil Forms... 9 8.1.1 Hutton Soil Form... 9 8.1.2 Longlands Soil Form... 9 8.1.3 Avalon Soil Form... 9 8.1.4 Mispah Soil Form... 9 8.2 Example of Future Operations... 10 8.3 Land Capability... 11 8.3.1 Class II: Intensive Cultivation... 11 8.3.2 Class III: Moderate Cultivation... 11 8.4 Land Use... 14 9 Potential Impacts... 16 Digby Wells Environmental v
10 Impact Assessment... 16 10.1 Methodology used in Determining and Ranking the Nature, Significance, Consequence, Extent, Duration and Probability of Potential Environmental Impacts and Risks... 16 10.2 Impact Assessment... 24 10.2.1 Operational Phase... 24 10.2.2 Decommissioning Phase... 28 11 Unplanned Events and Low Risks... 32 12 Environmental Management Plan... 32 12.1 Soil Stripping... 33 12.1.1 Stripping Guideline... 33 12.1.2 Stripping Method... 33 12.1.3 Stockpiling... 33 12.1.4 Supervision... 34 12.1.5 Soil Replacement... 34 12.1.6 Soil Amelioration... 35 12.2 Summary of Mitigation and Management... 35 12.3 Monitoring Plan... 38 13 Conclusion and recommendations... 39 14 References... 40 LIST OF FIGURES Figure 8-1: The Land Type map for the Elandsfontein Colliery EMP Amendment (Land Type Survey Staff, 1976-2006)... 8 Figure 8-2: Current Operations, Soils being Stripped and Stockpiled Separately... 10 Figure 8-3: The Land Capability map for the Elandsfontein Colliery EMP Amendment (Land Type Survey Staff, 1976-2006)... 13 Figure 8-4: The Land Use Map for the Elandsfontein Colliery EMP Amendment... 15 Digby Wells Environmental vi
LIST OF TABLES Table 6-1: Land Capability Classes... 4 Table 8-1: Dominant Land Type and Soil Forms... 9 Table 10-1: Impact Assessment Parameter Ratings... 18 Table 10-2: Probability/Consequence Matrix... 22 Table 10-3: Significance Rating Description... 23 Table 10-4: Project Activities... 24 Table 10-5: Interactions and Impacts during Operational phase... 24 Table 10-6: Potential Impacts for the Loss of Stockpiled Topsoil... 26 Table 10-7: Potential Loss of Land Use and Land Capability... 27 Table 10-8: Interactions and Impacts during Decommissioning and Rehabilitation... 28 Table 10-9: Impact Rating for Loss of Topsoil as a Resource: Compaction and Erosion... 29 Table 10-10: Impact Rating for Rehabilitation and of Open pit areas... 31 Table 11-1: Unplanned Events, Low Risks and their Management Measures... 32 Table 12-1: Soils, Land Use and Land Capability Mitigation and Management Plan... 36 Table 12-2: Objectives and Outcomes of the EMP... 36 Table 12-3: Mitigation for Soils, Land Use and Land Capability... 37 Table 12-4: Prescribed Environmental Management Standards, Practice, Guideline, Policy or Law... 37 Digby Wells Environmental vii
1 Introduction Digby Wells Environmental (hereafter Digby Wells) was requested by Anker Coal and Mineral Holdings SA (Pty) Ltd to update, amend the approved Environmental Management Programme (EMP) and renewal of Mining Right (MR) MP314MR for its Elandsfontein Operations (Colliery) near Witbank in Mpumalanga Province. Elandsfontein holds two mining rights (MP314MR and MP63MR) situated adjacent to each other. This project focuses solely on MP314MR and the activities associated with this part of the Colliery. 1.1 Background Elandsfontein Colliery was developed by Fraser Alexander in the 1980 s and sold to Anker Coal in 1997. The EMP (1999) for the Elandsfontein Colliery was approved in terms of the Minerals Act (Act No. 51 of 1991) on 11 October 1999. The Mine consisted of the underground and as well as opencast activities. Currently opencast mining has resumed at Elandsfontein Colliery. Discard material is being reprocessed at the existing wash plant. Discard from the wash plant is disposed of on the footprint of the old discard dump. Areas within the Colliery have also been rehabilitated to varying degrees. Mining on MP314MR consisted mostly of underground mining and some opencast sections. Discard from the wash plant was disposed of on the footprint of the old discard dump. Slurry was filter pressed and sold. Areas within the Colliery have also been rehabilitated to varying degrees. 1.2 Project Activities Elandsfontein is an existing operation and the necessary infrastructure is already in place. No additional infrastructure is proposed as part of this amendment process. Opencast mining is the only new activity proposed. The following activities will be associated with the opencast mining: Removal of vegetation and topsoil; Stockpiling of topsoil; Removal of overburden; Stockpiling of overburden; Mining of coal from the open pit and old discard dump; and Transportation of material to relevant stockpiles. Digby Wells Environmental 1
2 Terms of Reference The soil, land use and land assessment will make use of the existing baseline soils assessment undertaken. The proposed update will be done at a desktop level. The following tasks were undertaken in the compilation of the soil, land use and land capability assessment: Review of all existing soils information conducted; Updating soil delineation, land capability and land use maps; and Updating impact assessment with associated activities of the current open pit mining. 3 Aims and Objectives This report aimed to provide an accurate record of the soil resources of the study area through provision of the following data: The land type data describing the soil types found on the study area; Description of current land capability and land use; Soil management plan; Stripping depths; Soil stripping guidelines; and Soil utilisation guideline. Impact assessment of the current open pit mining activities on the soil, land capability and land use; and Mitigation measurements to manage the existing and expected impacts on the soil, land capability and land use. 4 Details of the Authors The following is a list of the Digby Wells staff who were involved in compilation of the soils assessment report and peer review for Elandsfontein Colliery EMP: Siphamandla Madikizela is a Soil Scientist and completed his MSc in Soil Science at University of KwaZulu-Natal. Prior to his employment at Digby Wells Environmental, Siphamandla worked as an Assistant Plantation Manager at EcoPlanet Bamboo SA. He is the part of the Closure, Rehab and Soils Department at Digby Wells Environmental. His role involves conducting soil surveys, identification of soil forms, interpreting results of soil samples and writing detailed scientific reports. Brett Coutts: Rehabilitation Unit Manager received a Bachelor of Science and Honours degree in Zoology and Environmental Science from the University of Witwatersrand. Brett assists with the management and co-ordination of all relevant studies related to rehabilitation. This includes the compilation of rehabilitation plans and undertaking of Digby Wells Environmental 2
rehabilitation assessments. In addition to this, Brett assists within the Biophysical Department with the management of specialist studies that are undertaken by the department and is also responsible for the compilation of the Geographic Information System (GIS) component of Biodiversity Land Management Plans (BLMP) and undertaking ecological assessments. He previously worked for Hydromulch, a company that specialises in vegetation rehabilitation. 5 Environmental Law Applicable to Study The South African Environmental Legislation needs to be considered with the reference to the management of soil and land use which includes: Soils and land capability area protected under the National Environmental Management Act 107 of 1998, the Minerals Act of 2002 and the Conservation of Agricultural Resources Act 43 of 1983; The National Environmental Management Act 107 of 1998 requires that pollution and degradation of the environment be avoided, or, where it cannot be avoided be minimised and treated; The Conservation of Agricultural Resources Act of 1983 states that the degradation of the agricultural potential of soil is illegal; and The Conservation of Agricultural Resources Act 43 of 1983 requires that protection of land against soil erosion and the prevention of water logging and salinization of soils means of suitable soil conservation works to be constructed and maintained. The utilisation of marshes, water sponges and water courses are also addressed. 6 Methodology 6.1 Desktop Assessment Digby Wells conducted a desktop review of all baseline data and findings related to the soil surveys previously undertaken. The following sources of information were reviewed and utilised for the compilation of this report: Environmental Management Programme. Elandsfontein Colliery. AV Environmental Management Services cc. 1999; and Elandsfontein Baseline Environmental Study. Rehabilitated Land Capability and Soil Cover Material Assessment Report. Digby Wells Environmental. January 2015. 6.2 Site Assessment The site was traversed by vehicle and on foot. Previously rehabilitated land areas were visited and auger was used to see the soil depth. No soil samples were taken from the rehabilitated areas as some areas rehabilitation was successful. Digby Wells Environmental 3
6.3 Land Capability Land capability was determined by a combination of soil, terrain and climate features. Land capability is defined by the most sustainable land use under rain-fed conditions. Land capability was categorised into the classes listed in Table 6-1. Table 6-1: Land Capability Classes Land Capability Class Increased Intensity of Use Land Capability Groups I W F LG MG IG LC MC IC VIC II W F LG MG IG LC MC IC III W F LG MG IG LC MC Arable Land IV W F LG MG IG LC V W LG MG VI W F LG MG VII W F LG Grazing Land VIII W Wildlife W Wildlife MG - Moderate Grazing MC - Moderate Cultivation IG - Intensive Grazing IC - Intensive Cultivation LG - Light Grazing F- Forestry LC - Light Cultivation VIC - Very Intensive Cultivation Land capability as defined in South Africa, can be classified using two approaches. The first approach is used in agriculture and is recommended by Schoeman et al (2000) who defined land capability in terms of the combined effects of soil, terrain and climatic features. The defined land capability shows the most intensive long-term use of land for rain-fed agriculture and at the same time indicates the permanent limitations associated with different land use classes. The classification system is made up of land capability classes and land capability groups (Table 6-1). The second approach is contained in the Coaltech Research Association and the Chamber of Mines of South Africa Guidelines for the Rehabilitation of Mined Land, 2007. These 2007 Guidelines recommend the following classes of post mining rehabilitated land: arable, grazing, wilderness and wetland. The following criteria are used to define these classes: Digby Wells Environmental 4
Arable: The soil depth exceeds 0.6 m, the soil material is not sodic or acidic and slope percentage is such that when multiplied by the soil erodibility factor K, the product does not exceed a value of 2.0; Grazing: The soil depth is less than 0.6 m but more than 0.25 m; Wilderness: The soil depth is less than 0.25 m but more than 0.15 m; and Wetland: The soil depths are as for grazing but soil must be used for the construction of wetlands. These wetland soils must be separately stockpiled. 6.4 Land Use The current land use was identified by aerial imagery; review of existing information and by on-site inspection. The land use is classified as follows: Plantations; Natural; Waterbodies; Mines; Urban built-up; and Cultivated. 7 Existing Information 7.1 Soils Soil survey was conducted on the farm Elandsfontein to establish to the soil types found on the area. The Hutton soil form occupied larger portion followed by Longlands, Avalon and Mispah. Hutton soils occupy the upper slope positions; Avalon soils occupying the mid-slope positions; Longlands occupying the lower slopes; and Mispah occupying the lower mid-slope positions. Soils are sandy and slightly heavier textured with depth. Soils are dystrophic, meaning they are acidic, have a very low base status and generally infertile. Soils are not highly erodible; however slope soils such as Longlands can be potentially erodible. Larger part of the area occupied by Hutton and Avalon soils is arable; Mispah and Longlands soils are only suitable for grazing. 7.2 Soil Fertility From previous assessment done by Digby Wells (2015); soil samples were collected and analysed for soil acidity and basic fertility as follows: Soil ph (H 2 O); Cations: Ca, Mg, Na and K (Ammonium acetate); and Phosphorus (Bray1). Digby Wells Environmental 5
In general, the acidity level of the soils is very acidic to slightly acidic, ph below 6 could be a limiting factor to plant growth and the project area would require the addition of agricultural lime or gypsum to remedy soil acidity. It is generally accepted that levels of phosphorus around 20 mg kg -1 constitute adequate levels for plant production. Phosphorus availability is low in the soils and could be limiting on ecosystem function and fertilisation would be required to establish good crop stand and growth. Soil samples collected on the site show the profile Ca>Mg>K>Na concentrations as expected. Sodium concentrations ranged from 12 to 102 mg kg -1, these levels are below the high concentration mark according to the soil fertility guidelines (FASA, 2003), soil dispersion is unlikely to occur and cause dense structure and drainage problems (de Villiers et al., 2003). Potassium concentrations ranged from 21 to 95 mg kg -1 with a high value of 208 mg kg -1 and these levels are low to moderate. Magnesium and Calcium concentrations were below the high concentration mark and addition of fertilisation is required to increase the levels and promote good growth. 7.3 Rehabilitated Areas The rehabilitated land was surveyed in 2015 and the land was classified according to the post mining land capability criteria (2007). Results were mapped according to capability and discussed. The soils found are within the land type Ba5 and Bb13. Geology underlying the land types consist of shale, grit, sandstone, conglomerate of the Ecca Group and dolerite of the Karoo sequence. The soil ph of the rehabilitated area was found to be acidic and nutrient content (Ca, Mg, K and Na) of the soil was classified as low, therefore requires amelioration. The following conclusions were made from the soil survey conducted in 2015: Area A Rehabilitated area of 3.5 ha with soil cover was mapped and approximately 25.3 ha of reshaped overburden material were not rehabilitated. The land capability for the rehabilitated area was classified as grazing. Area B 15.8 ha of land has been rehabilitated and land capability classified as arable, while 34.6 ha of land was classified as grazing land capability. 2.7 ha of land was poorly rehabilitated and classified as wilderness. Area C 5.9 ha of land was rehabilitated with land capability of arable and grazing. Un-rehabilitated land occupied 2 ha of the area. Digby Wells Environmental 6
8 Current Assessment Findings The land type data gathered suggested that the dominant land types on site were Ba5 and Bb13 (Figure 8-1). Further information related to the soil within the study area is discussed in Section 8.1. The proposed area for open pit mining is dominated by Hutton, Avalon, Longlands and Mispah soil forms. The area is dominated by the presence of soils highly suited to agriculture such as Hutton and Avalon. The remainder of the area consists of soils with low agricultural potential. Digby Wells Environmental 7
Figure 8-1: The Land Type map for the Elandsfontein Colliery EMP Amendment (Land Type Survey Staff, 1976-2006) Digby Wells Environmental 8
8.1 Land Type Data and Soil Forms Table 8-1: Dominant Land Type and Soil Forms Land Type Soil Forms Geology Ba5 Bb13 Mispah, Hutton, Avalon and Longlands Avalon, Hutton and Longlands Shale, hornfels and chert of the Silverton Formation, Pretoria Group, tillite and shale of the Dwyka Formation, diabase, shaly sandstone, conglomerate of the Ecca Group and agglomerate and lava. Sandstone, grit, shaly sandstone and shale of the Ecca Group and Karoo Sequence. 8.1.1 Hutton Soil Form The Hutton soil form consists of an Orthic A and red apedal B over unspecified material. These soils are well drained, usually slightly acidic, and have a low cation exchange capacity (CEC) due mainly to clay mineral composition (kaolinite, iron oxides) and sometimes low clay content. This soil form was identified in relatively flat landscape positions and has high arable potential and high value for use as topsoil, having favourable structure (weak blocky to apedal) and consistence (slightly firm to friable). 8.1.2 Longlands Soil Form The Longlands soil form consists of Orthic A on an E horizon, over soft plinthic B subsoil. The intermittent saturation in E horizon results in periodic anaerobic conditions in Longlands soil form, causing dissolved iron oxides to be deposited to an insoluble state in the form of mottling of the soft plinthic B horizon. From a land use point of view, the Longlands soil form has a low to moderate agricultural potential. The waterlogged, anoxic conditions can present problems with rooting depth. Artificial drainage can mitigate high saturation and the application of lime and gypsum can alleviate toxicity and improve the rooting depth of crops such as maize (Fey et al., 2010). 8.1.3 Avalon Soil Form The Avalon soil form consists of Orthic A, on a yellow-brown apedal B, over a soft plinthic B horizon. Avalon soils are freely draining and chemically active. Manganese and iron oxides accumulate under conditions of a fluctuating water table forming localised mottles or soft iron concretions of the soft plinthic B horizon. Mottling in the samples found within the study site was yellow-brown in colour and occupied at least 10% of the horizon (Fey et al., 2010). 8.1.4 Mispah Soil Form The Mispah soil form consists of an orthic A over hard rock material. These soils are shallow, have a low agricultural potential, usually a high erosion hazard and have limited rooting depth. Digby Wells Environmental 9
8.2 Example of Future Operations Current operations at Elandsfontein Colliery include stripping of soils and stockpiling for later use in Rehabilitation (Figure 8-2). Figure 8-2: Current Operations, Soils being Stripped and Stockpiled Separately Digby Wells Environmental 10
8.3 Land Capability Land capability is determined by a combination of soil, terrain and climate features. The dominant land capability classes in the project area were Class II (Intensive cultivation) and Class III (Moderate cultivation) as depicted in Figure 8-3. The ensuing paragraphs list in detail the limitations used to define the two classes. 8.3.1 Class II: Intensive Cultivation Class II land capability coincides with the Hutton and Clovelly soils. These soils are well drained, easily managed and have high agricultural potential. Land in Class II has some limitations that reduce the choice of plants or require moderate conservation practices. It may be used for cultivated crops, but with less latitude in the choice of crops or management practices than Class I. The limitations are few and the practices are easy to apply. Limitations may include, singly or in combination, the effects of: Gentle slopes; Moderate susceptibility to wind and water erosion; Less than ideal soil depth; Somewhat unfavourable soil structure and workability; Slight to moderate salinity or sodicity easily corrected but likely to recur; Occasional damaging flooding; Wetness correctable by drainage but existing permanently as a moderate limitation; and Slight climatic limitations on soil use and management. Limitations may cause special soil-conserving cropping systems, soil conservation practices, water-control devices or tillage methods to be required when used for cultivated crops. 8.3.2 Class III: Moderate Cultivation Land in Class III has more severe limitations that reduce the choice of plants or require special conservation practices or both. Land may be used for cultivated crops, but has more restrictions than Class II. When used for cultivated crops, the conservation practices are usually more difficult to apply and to maintain. The number of practical alternatives for average farmers is less than that for soils in Class II. Limitations restrict, singly or in combination, the amount of clean cultivation, time of planting, tillage, harvesting and choice of crops. Limitations may result from the effects of one or more of the following: Moderately steep slopes; High susceptibility to water or wind erosion or severe adverse effects of past erosion; Frequent flooding accompanied by some crop damage; Digby Wells Environmental 11
Very slow permeability of the subsoil; Wetness or some continuing waterlogging after drainage; Shallow soil depth to bedrock, hardpan, fragipan or clay-pan that limits the rooting zone and water storage; Low water-holding capacity; Low fertility not easily corrected; Moderate salinity or sodicity; and Moderate climatic limitations. Digby Wells Environmental 12
Figure 8-3: The Land Capability map for the Elandsfontein Colliery EMP Amendment (Land Type Survey Staff, 1976-2006) Digby Wells Environmental 13
8.4 Land Use The land use at Elandsfontein are mainly mining activities and grazing (Figure 8-4). Surrounding land use can be broadly defined as mining and grazing land. With the current open pit activities; land cover will change from grassland to non-usable for grazing until land is rehabilitated. Digby Wells Environmental 14
Figure 8-4: The Land Use Map for the Elandsfontein Colliery EMP Amendment Digby Wells Environmental 15
9 Potential Impacts The major impact associated with open pit mining is the disturbance of the naturally occurring soil profiles consisting of soil horizons. The impact on the soil is high because natural soil horizons are stripped and stockpiled for later use in rehabilitation. Soil fertility is adversely affected because soil horizon thickness does not coincide with that of the defined topsoil layer. The topsoil is where most plant roots are found and is generally about 0.3 m thick. Topsoil contains organic matter which is linked to nutrient cycling, improving soil fertility. Mixing topsoil with subsoil dilutes soil fertility and impacts on microbial activity leading to soil quality degradation in stockpiles over time. The impacts on soils associated with open pit mining can be split up into the following: Dilution of topsoil through mixing with subsoil and deeper lying materials; Decline in organic matter content and biological activity during stockpiling; Compaction and loss of soil structure; Disconnection of soil type with original landscape position, hence destruction of the toposequence; and Unfeasibility of reconstructing soil profile hydrology, especially the proportions of runoff, infiltration, interflow and through flow of rain water, especially in cases where less permeable subsurface horizons consisting of clay, plinthite or rock were present initially. 10 Impact Assessment 10.1 Methodology used in Determining and Ranking the Nature, Significance, Consequence, Extent, Duration and Probability of Potential Environmental Impacts and Risks Details of the impact assessment methodology used to determine the significance of physical, bio-physical and socio-economic impacts are provided below. Digby Wells Environmental 16
The significance rating process follows the established impact/risk assessment formula: Significance = Consequence x Probability x Nature Where Consequence = Intensity + Extent + Duration And Probability = Likelihood of an impact occurring And Nature = Positive (+1) or negative (-1) impact Note: In the formula for calculating consequence, the type of impact is multiplied by +1 for positive impacts and -1 for negative impacts The matrix calculates the rating out of 147, whereby Intensity, Extent, Duration and Probability are each rated out of seven as indicated in Table 10-3. The weight assigned to the various parameters is then multiplied by +1 for positive and -1 for negative impacts. Impacts are rated prior to mitigation and again after consideration of the mitigation measure proposed in this EIA/EMP Report. The significance of an impact is then determined and categorised into one of eight categories, as indicated in Table 10-2, which is extracted from Table 10-1. The description of the significance ratings is discussed in Table 10-3. It is important to note that the pre-mitigation rating takes into consideration the activity as proposed, i.e. there may already be certain types of mitigation measures included in the design (for example due to legal requirements). If the potential impact is still considered too high, additional mitigation measures are proposed. Digby Wells Environmental 17
Intensity/Replicability Table 10-1: Impact Assessment Parameter Ratings Rating Negative Impacts (Nature = -1) Positive Impacts (Nature = +1) Extent Duration/Reversibility Probability 7 Irreplaceable loss or damage to biological or physical resources or highly sensitive environments. Irreplaceable damage to highly sensitive cultural/social resources. Noticeable, on-going natural and / or social benefits which have improved the overall conditions of the baseline. International The effect will occur across international borders. Permanent: The impact is irreversible, even with management, and will remain after the life of the project. Definite: There are sound scientific reasons to expect that the impact will definitely occur. >80% probability. 6 Irreplaceable loss or damage to biological or physical resources or moderate to highly sensitive environments. Irreplaceable damage to cultural/social resources of moderate to highly sensitivity. Great improvement to the overall conditions of a large percentage of the baseline. National Will affect the entire country. Beyond project life: The impact will remain for some time after the life of the project and is potentially irreversible even with management. Almost certain / Highly probable: It is most likely that the impact will occur. <80% probability. Digby Wells Environmental 18
Intensity/Replicability Rating Negative Impacts (Nature = -1) Positive Impacts (Nature = +1) Extent Duration/Reversibility Probability 5 Serious loss and/or damage to physical or biological resources or highly sensitive environments, limiting ecosystem function. Very serious widespread social impacts. Irreparable damage to highly valued items. On-going and widespread benefits to local communities and natural features of the landscape. Province/ Region Will affect the entire province or region. Project Life (>15 years): The impact will cease after the operational life span of the project and can be reversed with sufficient management. Likely: The impact may occur. <65% probability. 4 Serious loss and/or damage to physical or biological resources or moderately sensitive environments, limiting ecosystem function. On-going serious social issues. Significant damage to structures / items of cultural significance. Average to intense natural and / or social benefits to some elements of the baseline. Municipal Area Will affect the whole municipal area. Long term: 6-15 years and impact can be reversed with management. Probable: Has occurred here or elsewhere and could therefore occur. <50% probability. Digby Wells Environmental 19
Intensity/Replicability Rating Negative Impacts (Nature = -1) Positive Impacts (Nature = +1) Extent Duration/Reversibility Probability 3 Moderate loss and/or damage to biological or physical resources of low to moderately sensitive environments and, limiting ecosystem function. On-going social issues. Damage to items of cultural significance. Average, on-going positive benefits, not widespread but felt by some elements of the baseline. Local Local extending only as far as the development site area. Medium term: 1-5 years and impact can be reversed with minimal management. Unlikely: Has not happened yet but could happen once in the lifetime of the project, therefore there is a possibility that the impact will occur. <25% probability. 2 Minor loss and/or effects to biological or physical resources or low sensitive environments, not affecting ecosystem functioning. Minor medium-term social impacts on local population. Mostly repairable. Cultural functions and processes not affected. Low positive impacts experience by a small percentage of the baseline. Limited Limited to the site and its immediate surroundings. Short term: Less than 1 year and is reversible. Rare / improbable: Conceivable, but only in extreme circumstances. The possibility of the impact materialising is very low as a result of design, historic experience or implementation of adequate mitigation measures. <10% probability. Digby Wells Environmental 20
Intensity/Replicability Rating Negative Impacts (Nature = -1) Positive Impacts (Nature = +1) Extent Duration/Reversibility Probability 1 Minimal to no loss and/or effect to biological or physical resources, not affecting ecosystem functioning. Minimal social impacts, low-level repairable damage to commonplace structures. Some low-level natural and / or social benefits felt by a very small percentage of the baseline. Very limited/isolated Limited to specific isolated parts of the site. Immediate: Less than 1 month and is completely reversible without management. Highly unlikely / None: Expected never to happen. <1% probability. Digby Wells Environmental 21
Probability Soils, Land Use and Land Capability Impact Assessment Table 10-2: Probability/Consequence Matrix Significance 7-147 -140-133 -126-119 -112-105 -98-91 -84-77 -70-63 -56-49 -42-35 -28-21 21 28 35 42 49 56 63 70 77 84 91 98 105 112 119 126 133 140 147 6-126 -120-114 -108-102 -96-90 -84-78 -72-66 -60-54 -48-42 -36-30 -24-18 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120 126 5-105 -100-95 -90-85 -80-75 -70-65 -60-55 -50-45 -40-35 -30-25 -20-15 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 4-84 -80-76 -72-68 -64-60 -56-52 -48-44 -40-36 -32-28 -24-20 -16-12 12 16 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 84 3-63 -60-57 -54-51 -48-45 -42-39 -36-33 -30-27 -24-21 -18-15 -12-9 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 2-42 -40-38 -36-34 -32-30 -28-26 -24-22 -20-18 -16-14 -12-10 -8-6 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 1-21 -20-19 -18-17 -16-15 -14-13 -12-11 -10-9 -8-7 -6-5 -4-3 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21-21 -20-19 -18-17 -16-15 -14-13 -12-11 -10-9 -8-7 -6-5 -4-3 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Consequence Digby Wells Environmental 22
Table 10-3: Significance Rating Description Score Description Rating 109 to 147 73 to 108 36 to 72 3 to 35-3 to -35-36 to -72-73 to -108-109 to -147 A very beneficial impact that may be sufficient by itself to justify implementation of the project. The impact may result in permanent positive change A beneficial impact which may help to justify the implementation of the project. These impacts would be considered by society as constituting a major and usually a long-term positive change to the (natural and / or social) environment A positive impact. These impacts will usually result in positive medium to long-term effect on the natural and / or social environment A small positive impact. The impact will result in medium to short term effects on the natural and / or social environment An acceptable negative impact for which mitigation is desirable. The impact by itself is insufficient even in combination with other low impacts to prevent the development being approved. These impacts will result in negative medium to short term effects on the natural and / or social environment A minor negative impact requires mitigation. The impact is insufficient by itself to prevent the implementation of the project but which in conjunction with other impacts may prevent its implementation. These impacts will usually result in negative medium to long-term effect on the natural and / or social environment A moderate negative impact may prevent the implementation of the project. These impacts would be considered as constituting a major and usually a longterm change to the (natural and / or social) environment and result in severe changes. A major negative impact may be sufficient by itself to prevent implementation of the project. The impact may result in permanent change. Very often these impacts are immitigable and usually result in very severe effects. The impacts are likely to be irreversible and/or irreplaceable. Major (positive) (+) Moderate (positive) (+) Minor (positive) (+) Negligible (positive) (+) Negligible (negative) (-) Minor (negative) (-) Moderate (negative) (-) Major (negative) (-) Digby Wells Environmental 23
10.2 Impact Assessment The impact assessment is aimed at identifying impacts related to the various activities listed in from a soils perspective. The activities associated with soil impacts are highlighted in grey below and discussed within the impact and risk sections below. 1 Stripping topsoil and soft overburden; Table 10-4: Project Activities Operational 2 Removal of overburden, including drilling and blasting of hard overburden; 3 Loading, hauling and stockpiling of overburden; 4 Load, haul and stockpiling of RoM coal; 5 Use and maintenance of haul roads for the transportation of coal to the washing plant; Decommissioning 6 Rehabilitation, including spreading of soil, re-vegetation and profiling or contouring; 7 Post-closure monitoring and rehabilitation. 10.2.1 Operational Phase 10.2.1.1 Project Activities Assessed During the operational phase, erosion and compaction of all exposed areas and land capability and land use are the major impacts to consider. Table 10-5: Interactions and Impacts during Operational phase Interaction Impact Soil erosion due to wind and surface water runoff The construction of stockpiles Loss of Land Capability Loss of Land Use Loss of topsoil as a resource Operation and maintenance of the topsoil Loss of topsoil as a resource: compaction and erosion 10.2.1.1.1 Impact Description: Loss of Stockpiled Soil When topsoil is compacted or eroded, the soil profile is compromised and its ability to function as a growth medium is restricted. The movement of heavy machinery on the soil surface causes compaction which reduces the vegetation s ability to grow and as a result the risk of erosion will increase. The loss of topsoil will have a high negative impact and the natural regeneration of few millimetres of topsoil takes hundreds of years. Digby Wells Environmental 24
10.2.1.1.2 Impact Description: Loss of Land Use and Land Capability When topsoil is removed from the open pit, the land capability is reduced to nothing and land use will change from intensive cultivation to mining. There is loss of agricultural potential and topsoil degradation. The land capability during this phase will be reduced from classifiable to non-classifiable. 10.2.1.1.3 Management Objectives The following management objectives are to limit the impacts that could occur on the site: If erosion occurs, corrective actions must be taken to limit and reduce the impact from spreading; Bare areas need to be assessed for compaction and ripped if required; and Stripped red and yellow soils should not be stockpiled and stored together. These soils must be monitored and maintained in a reasonably fertile state. 10.2.1.1.4 Management Actions and Targets The following management actions and targets are provided: Ensure proper storm water management designs are in place; The topsoil should be stripped by means of an excavator bucket and loaded onto dump trucks; If possible topsoil should be stripped when the soil is dry, as to reduce compaction; Topsoil stockpiles are to be kept to a maximum height of 4 m; Topsoil of 0.3 m of the soil profile should be stripped first and stockpiled separately; The subsoil of 0.4 to 1.2 m will then be stripped and stockpiled separately for deep soils like Hutton and Avalon; Hutton and Avalon can be stripped and stockpiled together since their soil properties are similar; If any erosion occurs, corrective actions must be taken to minimise any further erosion from taking place; If erosion has occurred, topsoil should be sourced and replaced, shaped to reduce the recurrence of erosion; and Only the designated access routes are to be used to reduce any unnecessary compaction. 10.2.1.1.5 Impact Ratings The operational phase impacts described are rated in Table 10-6 and Table 10-7. Digby Wells Environmental 25
Table 10-6: Potential Impacts for the Loss of Stockpiled Topsoil Dimension Rating Motivation Significance Activity and Interaction: 1, 2, 3, 4 and 5 Impact Description: During the operational phase vegetation will be stripped resulting in the exposure of soil to natural elements this can make the soil more susceptible to erosion as a result of rainfall and wind. Additionally the quality of soil will deteriorate with increasing exposure to the natural element and erosion. Prior to Mitigation/Management Duration 5 Extent 3 Intensity 5 Probability 7 Largest volumes of topsoil will be removed in preparation of open pit mining but may last after this phase Loss of topsoil will only occur within project area Loss of usable topsoil may result in loss of land capability and land use. Soil regeneration takes a very long time. By excavating the soil it will certainly impact on the soil Moderate (negative) - 91 Nature Negative Mitigation/Management Actions Follow adequate stripping guidelines in Section 12; Topsoil should be stripped by means of an excavator bucket and loaded onto dump trucks; If possible topsoil should be stripped when soil is dry, as to reduce compaction Ensure topsoil is stored in one dedicated stockpile, 4 m high and away from drainages lines and surface water; Only the designated access routes are to be used; If erosion occurs, corrective actions must be taken to minimise any further erosion from taking place; Stockpiles are to be maintained in a fertile and erosion free state by sampling and analysing annually for macro nutrients and soil ph, and vegetating the stockpiles to reduce erosion; Compaction of the removed topsoil should be avoided by prohibiting traffic on stockpiles; Prevent unauthorised borrowing of stockpiled soil; and Ensure proper storm water management designs are in place. Post-Mitigation Digby Wells Environmental 26
Dimension Rating Motivation Significance Duration 5 Extent 2 Intensity 3 Probability 4 Loss of topsoil makes land less productive. Usable soil will be stripped and stockpiled if this is done without following the mitigation measures the impact might have a long term effect. Effects will occur long after the project life Loss of soil will only occur within project area Loss of usable soil may result in loss of good productive soils By excavating the soil it will certainly impact on soil Minor (negative) - 40 Nature Negative Table 10-7: Potential Loss of Land Use and Land Capability Dimension Rating Motivation Significance Activity and Interaction: 1, 2, 3, 4 and 5 Impact Description: During the mining operation, topsoil will be removed from the open pit. This loss of topsoil will have a direct impact on land capability. The land use will be converted from grazing to mining. As the pit expands in size the level of this impact increases as larger areas of land are converted. Prior to Mitigation/Management Duration 7 Extent 2 Intensity 5 Probability 7 The impact will be permanent, reducing capability Loss of land capability and land use will occur on a limited scale Loss of natural soils is serious and will have a negative impact on land use and land capability The impact on land capability and land use is certain as it changes from arable to non-arable and from intensive cultivation to mining Moderate (Negative) - 96 Nature Negative Mitigation/Management Actions Digby Wells Environmental 27
Dimension Rating Motivation Significance No land capability mitigation is possible during the operational phase because the land use is changed from agriculture to open pit mining. Therefore the impact is expected to stay the same as discussed above. 10.2.2 Decommissioning Phase 10.2.2.1 Project Activities Assessed The major impacts to consider in the decommissioning and rehabilitation of the site will be the loss of topsoil as a resource through erosion and compaction. When the decommissioning and removal of infrastructure takes, vehicles will drive on the surface compacting it and this reduces infiltration rates as well as the ability for plant roots to penetrate the compacted soil. Vegetation cover will be reduced and increases runoff potential, therefore increased runoff potential leads to increased erosion hazards. During the decommissioning and rehabilitation phase, the open pit will be rehabilitated as per the rehabilitation guideline (See Rehabilitation Report). Table 10-8: Interactions and Impacts during Decommissioning and Rehabilitation Interaction Rehabilitation activities will cover the extent of the infrastructure footprint areas and will include the ripping of the compacted soil surfaces, spreading of topsoil and establishment of vegetation Impact Loss of topsoil as a resource- erosion and compaction Loss of Land capability 10.2.2.1.1 Impact Description: Loss of Topsoil as a Resource Erosion and Compaction When topsoil is compacted or eroded, the soil profile loses effective rooting depth, water holding capacity and fertility. Movement of heavy machinery on the soil surface causes compaction, which reduces the vegetation s ability to grow and as a result erosion could be cause. The loss of topsoil as a resource is a serious impact as the natural regeneration of millimetres of topsoil takes hundreds of years 10.2.2.1.2 Impact Description: Loss of Land Use and Land Capability During rehabilitation and decommissioning phase, there will be a final void this significantly impacts on the final land capability and land use. The infrastructure areas can be rehabilitated and as a result the impact may be reduced if mitigation measures are implemented. Digby Wells Environmental 28
10.2.2.1.3 Management Objectives The rehabilitation process needs to be monitored for erosion. If erosion occurs corrective actions must be taken to limit and reduce the impact from spreading. Bare areas need to be assessed for compaction or contamination and ripped if required. If contamination has occurred, these soils need to be removed and dumped in a licensed landfill site. After the infrastructure removal and rehabilitated, the areas must be assessed for compaction and possible erosion risk and corrected immediately. 10.2.2.1.4 Management Actions and Targets The following management actions and targets are provided: Only the designated access routes are to be used to reduce any unnecessary compaction; Compacted areas are to be ripped to loosen the soil structure and vegetation cover re-instated; Implement land rehabilitation measures as defined in rehabilitation report; Topsoil should be replaced for rehabilitation purposes and used for their designated final purposes; Ensure proper storm water management designs are in place; Correction actions (erosion berms) must be taken to minimise any further erosion from taking place; The foundations of infrastructure must be removed; and Ensure proper storm water management designs are in place. 10.2.2.1.5 Impact Ratings The impacts are described in Table 10-9 and Table 10-10. Table 10-9: Impact Rating for Loss of Topsoil as a Resource: Compaction and Erosion Dimension Rating Motivation Significance Activity and Interaction: 6 and 7 Impact Description: Decommissioning and rehabilitation of the infrastructure and open pit areas could cause erosion and compaction if rehabilitation is not done correctly. Heavy machinery driving continuously over rehabilitated areas may result in compaction which could impact on plant rooting depth which then would have an impact to vegetation establishment. Prior to Mitigation/Management Duration 5 When the soil has eroded the impact will likely be permanent and potentially irreversible even with management. Moderate (negative) - 105 Digby Wells Environmental 29