Heritage Cases

Rehabilitation of the historically mined Pit on Portion 15 of the farm Jagersfontein 14IS in the Fauresmith District of the Free State though backfilling with coarse and fine tailings from the Jagersfontein Tailings Operation

CaseViews

CaseHeader

Status: 

HeritageAuthority(s): 

Development Type: 

ProposalDescription: 

Rehabilitation of the historically mined Pit on Portion 15 of the farm Jagersfontein 14IS in the Fauresmith District of the Free State though backfilling with coarse and fine tailings from the Jagersfontein Tailings Operation

Expanded_Motivation: 

Jagersfontein Developments (Pty) Ltd ("JD") proposes to backfill the old Jagersfontein open pit ("Pit") with fine tailings suspended in water ("Paste") and coarse tailings from its tailings processing operations ("Tailings Operations"). As the Pit has a surface area of 19.65 hectares (196,500m2) and the backfilling will change its character, the proposed project constitutes a development / activity as contemplated under section 38(1)(c)(i) of the NHRA, namely – "any development or other activity which will change the character of a site exceeding 5000m2 in extent". This document constitutes JD's motivation for undertaking the proposed development / activity and is submitted in support of its application for a permit in terms of section 38(1)(c)(i) of the NHRA ("Section 38 Application"). A permit was granted by SAHRA in 2013, authorising JD to backfill the Pit (“2013 Initial Section 35 Permit”), following an application under section 35 of the NHRA (“Section 35 NHRA Application”). Following an appeal by a third party to the Appeal Tribunal, established under the NHRA, the Initial Permit was set aside and redirected to the SAHRA for the reason that public participation was required. JD withdrew the Section 35 NHRA Application; and submitted an application under section 38 of the NHRA (“Section 38 Application”). It has obtained further specialists reports and conducted the required public participation (discussed below). Jagersfontein Developments (Pty) Ltd proposes to rehabilitate the historically mined pit (the "Pit" or "Site") on Portion 15 of the Farm Jagersfontein 14 IS, Fauriesmith District, Free State ("Farm Jagersfontein") as part of an initiative to restore the Pit's safety and to rehabilitate the surrounding environment, which will be done by removing the surface tailings dumps from the surface and backfilling the material into the Pit to create more space for agricultural activities. Portion 15 of the Farm Jagersfontein ("Portion 15") is owned by JD. The rehabilitation initiative will involve infilling the Pit with fine and coarse tailings ("Backfill Material") generated from JD's existing diamond extraction Plant (the "Plant") to make the bottom of the Pit shallower (the "Project"). The Project will require a water use licence from the Department of Water and Sanitation, in terms of section 40 of the National Water Act, 1998 (Act No. 36 of 1998), for the undertaking of a water use in terms of Section 21(g) of the NWA. According to a Geochemical Analyses conducted on the tailings and paste, it was concluded that the paste is potentially a Type 3 waste, which will require a liner consistent with a Class C liner. However, it was also found that the Backfill Material is sterile and immobile in this environment. Furthermore, as stated in the SRK Report (2021), a physical barrier (such as an HDPE liner, albeit that the installation of such a barrier is practically impossible), is not warranted or necessary since the slurry by virtue of its smectite clay content and very low permeability has the properties of an impermeable membrane over the pit floor and sidewalls and therefore results in a system deemed better than a Class C barrier system. A geohydrological simulation of the regional groundwater and 2 scenarios (i.e., Pit Backfilling and the Do-Nothing Option) showed that the Project will result in decreasing the groundwater pollution of the Tailings Operation footprint whereas the Do-Nothing option will result in continuous pollution and elevated levels of pollutants in the groundwater over a far longer period of time. Therefore, the proposed Project is beneficial to the surrounding environment for various reasons being: • All surface Tailings Dumps will be removed from the surface of the surrounding environment, processed and contained within the Pit, • Hydrology, runoff and surface water quality will improve when all surface tailings dumps are removed, • Groundwater in the shallow Valley Aquifer and superficial soils should improve with the removal of all the pollution sources from the surface, • Land-use will improve as more land will be available for communal agriculture, • The health and safety risks associated with the surface Tailings Dumps will be removed, and • The removal of the surface Tailings Dumps will have a positive impact on the aesthetics of the town. Apart from the above the simulations and models by GHT in 2021 revealed that the Project will not result in pollution in any of the aquifers and that pollution will be contained within the deep geology and will not move laterally or vertically. The Pit was formed in the 1870s when the Farm Jagersfontein was proclaimed a public digging. It is the biggest hand-excavated hole in the world and, given its historical value, is a heritage resource under section 3 of the National Heritage Resources Act, 1999 (Act No. 25 of 1999) (“NHRA”). The Pit has, however, not been given any formal protection by the South African Heritage Resources Agency (“SAHRA”) or the Free State Heritage Resource Authority (“FSHRA”) under the NHRA. It has an extent of 19.635ha and is a near-vertical sided hole, with some of the faces being more than 200m in height. The Pit is unstable, breaking back and poses vibration risks. The Pit's instability presents a very serious safety risk, potentially placing local residents at risk in the long term. Due to the safety risks, it cannot be accessed by the public and is therefore closed for public viewing. SRK (2021) confirmed that the proposed Project will not have a negative impact on the Pit stability. The backfilling of the Pit will stabilise the walls ensuring improved stability. JD appointed a geotechnical and structural engineering specialist, Dr. Graham Howell (Professional Civil Engineer, Corporate Consultant and ex-Chairman of SRK Consulting (SA) Pty Ltd ("SRK")), who has undertaken extensive and on-going assessments. Dr. Graham Howell has confirmed that using tailings forthe Pit's rehabilitation is the only viable and practical way to ensure its stability and eliminate associated risks. Please refer to the Jagersfontein Pit Backfill Design Report by Dr. G. Howell submitted with the WULA. The Farm Jagersfontein is scarred from mining operations that have been conducted for over 100 years and is in a state of environmental degradation. Processing of the tailings dumps and backfilling them into the Pit is an environmentally sound project, which will lead to land rehabilitation. A calculation by Dr. Howell indicated that, with the volume of tailings available to be processed, the Pit will be backfilled to a depth of approximately 30m from the top. This is however dependent on when the Backfilling will commence, and the volume of surface tailings available for reprocessing at that stage. If the Backfilling is authorized early, it is expected that this void will be smaller, as there will be more tailings available for backfilling of the Pit. The opposite is true should the project commence very late. It was determined by Dr. Howell that the coarse and fine tailings can be utilised for infilling to rehabilitate the Pit. Other than assisting in the rehabilitation of the surface area, this will restore the Pit's stability. It will also remove all current tailings from the Operational Site, ensuring more effective rehabilitation of this Site and creating opportunities for agricultural development. The Pit's rehabilitation will also lessen the groundwater impacts on the shallow aquifer, currently caused by the presence of tailings on the Operational Site. The total volume of tailings still to be processed on the surface of the Tailings Operation is approximately 36 Million tons (“Mt”), of which 25.6 Million cubic metres (“Mm3”) will be tailings backfilled into the Pit. The ‘usable’ volume of air space in the Pit (to level 1400mamsl) is 31Mm3. Accordingly, the remaining Backfill Material will only fill to Pit to a level some 30m below the rim (1371mamsl). From a historical and tourism viewpoint, therefore, the Pit's unique geology will still be observable once the Operations cease. In addition, the current potentially unstable Pit slopes will be buttressed by the Backfill Material and further break-back (towards the Jagersfontein Town and surrounding) will be mitigated. Since the Backfill Material will only reach to a level of 1371mamsl, which is below the upper aquifer depth, no effect on the regional usable aquifer will result. Processes undertaken at the Tailings Operation include the ploughing and / or ripping of the Tailings Dumps to loosen tailings before they are loaded onto conveyors, which transports the tailings to the Plant. The Plant consists of 4 X 75 tons/hour Dense Medium Separator Plants, which are used to separate the mineral particles in a sink-float process. A suspension of dense powder in water is used, which forms a heavier liquid, for the separation. This causes the heavier material, containing diamonds, to sink and the lighter material to float. The material is further separated into coarse tailings and fine tailings suspended in water. The fine tailings are then further dewatered to a ‘paste’ before being deposited. These products will be used to rehabilitate the Pit. The Plant has a minimum processing target of 300 tons of tailings per hour. JD has also introduced a pan plant in early 2019, which increased run of mine) production to 700tons per hour. Refer to Integrated Water and Wastewater Management Plan (Turn 180, 2021)

ApplicationDate: 

Tuesday, August 16, 2022 - 11:41

CaseID: 

19315

OtherReferences: 

Dept CaseReference DueDate FinalDecision
DWS WU22362 30/09/2022 Decision

ReferenceList: 

Images