1. DUMP SLOPE STABILITY - with special reference to effects of monsoonal rainfall
MINE PORTAL TEAM
CALL/WHATSAPP

2. INTRODUCTION
Mine dumps and their types (a) internal dump (b) external dump
Mine dump stability - critically important issue
Impact on economics and production of mine
Factors affecting dump slope stability
Methods of slope stability investigations
Impact of rainfall on slope stability - Case study of Goa mine
An empirical formula relating dump parameters and pore water pressure to FOS of slope.

4. Failure Modes and Failure Mechanism
Surface and edge slides
Shallow flow slide in presence of sufficient water and flowing parallel to the face
Base failure
Block translation- dump on inclined ground
Circular failure- fine grains in dump
Foundation circular failure
Toe spreading

5. SOURCE: bestcoaltradingblogspot.com

6. WASTE DUMP STABILITY: (a) A Geotechnical Perspective
Long and short term stability
Long term stability:
Increase in ground water table
Decrease in dump material strength
Rainfall Effects: (a) rainfall intensity
(b) rainfall duration
(c) rainfall pattern

7. (b) A geo-environmental perspective
Waste may contain heavy metals causing many problems in rainy seasons:
(a) agricultural canals
(b) agricultural yields and fish population
(c) heavy siltation and sediment deposits in river beds and creeks.

8. CASE STUDY State of Goa- 5% of area(18300 ha) is under mining land
Average annual rainfall- 3000mm
Open cut mining method in Sesa Goa Iron mines
Annual production: million tonne
1:3 ore O/B ratio resulting waste production of million cubic m
Detailed investigations of mine dump slope stability and geo- environmental issues considering high rainfall
Quantification of soil properties and increase in pore water pressure due to heavy rainfall

9. LOCATION, GEOLOGY AND CLIMATE OF STUDY AREA
Samples from Sesa Goa Ltd. Codli Mine
Goa is a rising plateau covering an area of 3700 square km and coastline extending over 100km
Iron, magnese, bauxite and silica sand extraction
Current study area is Sanguem Taluka South-Goa,Goa
South west monsoon: june to september with highest rainfall in june and lowest in feb
Annual rainfall: 3000 to 4000mm

11. MATERIALS AND METHODS
Soil sampling and testing: six samples each weighing 3kgs in plastic bags to retain moisture content were tested in labs.
Ground water analysis: 5 dug-wells were dug in which water level measurement mainly during rainy season for 4years.
Numerical modeling: general limiting equilibrium method to calculate FOS of slope

12. RESULTS (a) Material Properties

14. (b) Ground Water Monitoring

15. (c) Numerical Modelling

18. CONCLUSIONS Optimum dump slope dimensions for safe mining operations
Influence of monsoonal rainfall on FOS is dramatic
Compaction of material plays an important role
Heavy metals presence in dumps is dangerous
Personnel injuries as well as downstream environmental effects
An empirical model to study dump slope failures

19. REFERENCES
Yelllishetty M,Darlington WJ(2011), Effects of Monsoonal Rainfall on Waste Dump Stability and Respective Geo-environmental Issues-a case study
Cadwell, J.A., and Moss,A.S.E.(1981)The Simplified Analysis of Mine Waste Embankemennts, Symposium on Design of Non-Impounding Mine Waste Embankements, Denver,USA,AIME Fall Meeting
Chaulya S.K., Singh R.S., Chakraborty M.K. and Shrivastava B.K.(2000), Quantification of Stability of Improvement of Dump Stablisation
Juwarkar AA,Singh SK,Dubay K,Nimje M(2003), Reclamation of Iron Mine Spoil Dumps Using Integrated Biotechnological Approach, In: Proceedings of National Seminar on Status of Environmental Management in Mining Industry, IT-BHU,Jan 17-18,pp
Yellishetty M,Ranjith PG,Kumar DL(2009), Metal Concentration and Mobility in Unsaturated in Mine Wastes in Mining Areas of Goa,India. Resourbcouserv Recycle53:
Pathak K., Rao K.U.M.(2011), Draft Report for Study of Dump Slope Stability of Sukhinda Chromite Mines (Tata Steel)
Geotechnical and Geological Engg 18: ,200
Environmental Earth Science(2011) 63:
(13/08/20111)
(14/08/2011)