Engineering and enviro-management value of radius of influence estimate from mining excavation. Issue 4 (2nd October 2018)

• Record Type: Journal Article
• Authors: Yihdego, Yohannes
• Is Part Of: Journal of applied water engineering and research. Volume 6:Issue 4(2018)
• Page Start: 329
• Page End: 337
• Publication Date: 2018-10-02
• Subjects: radius of influence -- mining -- engineering -- sustainability -- confined -- unconfined -- environment protection; Water-supply engineering -- Periodicals; Water-supply engineering; Periodicals; 627.05
• DOI: 10.1080/23249676.2017.1287022
• Languages: English
• ISSNs: 2324-9676

Abstract

Abstract : In mining operations carried out below the water table, mine area could potentially affect the surrounding. With further deepening of the mine and quarry, the drawdown can impact on water supply wells and base flow. The variation in radius of influence under confined and unconfined aquifer condition is assessed using a hypothetical case study with three operational quarry sites. Average pit-wise radius of influence ( R 0 ) for the pit mine, under unconfined and confined aquifer conditions is 963 m and 61 km, respectively, whereas effective radius ( R e ) for total (cumulative) excavated mine area is 1.7 and 146 km, respectively. It means that the maximum and minimum value of overall impact/influence for the unconfined aquifer lies in-between 963 m and 1.7 km. Similarly that the maximum and minimum value of overall impact/influence for the confined aquifer lies in-between 61 and 146 km. Meanwhile, R e or effective radius for total (cumulative) excavated area seems more appropriate from evaluation viewpoint due to the overlapping (superposition) concentric mining quarries. Thus, assessment of quarry-wise and total radius of influence is of importance to fulfil targeted production, economically with minimum interruptions as part of the mine planning. Moreover, it helps us to assess, monitor and regulate the impact of a mine-dewatering program in the area. Also, the pumping test is often used to estimate radius of influence; it can trigger the inflow or radius of influence. Estimate of the radius of influence using analytical equation mainly independent of discharge/abstraction from the aquifer stands as a preferred choice for the prediction of radius of influence at the quarry/mine pit. There is a strong rationale that policies should be informed by such analytical assessment because it helps us to prevent or minimize negative impacts as part of regulation and pit-mining management and are useful tools for practitioners to design economically efficient and cost-effective in situ groundwater remediation systems, to contain contaminant plumes, to evaluate the surface–subsurface water interaction and to verify numerical models.