1️⃣ Introduction
Before starting or expanding a mine, hydrogeological investigations are mandatory to assess the behavior of groundwater, seepage patterns, and water hazard risks.
The DGMS, Indian Bureau of Mines (IBM), and MoEFCC emphasize that all mining projects must conduct scientific hydrogeological studies to ensure safe excavation and environmental protection.
2️⃣ Objectives of Hydrogeological Investigation
- To determine groundwater occurrence, flow, and quality.
- To assess aquifer parameters and recharge potential.
- To predict inflow rates into mine workings.
- To identify water hazard zones and risk level.
- To recommend preventive and control measures.
3️⃣ Stages of Hydrogeological Study
- (A) Preliminary Study: Regional mapping, collection of rainfall/aquifer data, and identification of nearby water bodies.
- (B) Detailed Investigation: Borehole drilling, piezometer installation, and groundwater monitoring.
- (C) Predictive Analysis: Groundwater modeling (e.g., MODFLOW), seasonal studies, and inflow estimation.
4️⃣ Important Hydrogeological Parameters
| Parameter | Unit | Significance |
|---|---|---|
| Hydraulic conductivity (K) | m/s | Permeability of rock strata |
| Transmissivity (T) | m²/day | Flow potential of aquifer |
| Storativity (S) | Dimensionless | Water volume stored per unit head |
5️⃣ Piezometer Installation
Purpose: To measure the water table or pressure head at various depths.
- Drill boreholes up to the aquifer zone.
- Lower perforated PVC pipe with a filter pack.
- Seal the annular space with clay/bentonite.
- Fit a measuring tube and data logger.
- Record water levels periodically.
6️⃣ Seepage and Inflow Monitoring
Continuous monitoring of seepage and inflow helps predict water hazards. Modern mines use automatic water level recorders (AWLR), telemetry sensors, and rainfall–runoff correlation models.
7️⃣ Risk Analysis before Mine Expansion
Before expansion, a risk assessment must include aquifer-mine intersection analysis, checking for nearby waterlogged workings, identifying permeable fault zones, predictive inflow modeling, and checking emergency pumping capacity.
⚡ Quick One-Liners (Revision Points)
- Hydrogeological study determines groundwater behavior.
- IBM and DGMS both require hydro studies before mine expansion.
- Piezometer measures water pressure head.
- MODFLOW is a common groundwater modeling tool.
- Hydraulic conductivity (K) = permeability.
- Transmissivity (T) = K × aquifer thickness.
- Storativity (S) indicates aquifer storage capacity.
- DGMS Reg. 244: Precautions against water danger.
- Rainfall correlation helps predict seasonal inflow.
- Reports must be approved before MoEFCC clearance.
🧠 Descriptive Model Answer
Q. Explain the importance and procedure of hydrogeological investigations in mining projects as per DGMS and IBM guidelines.
Answer: Hydrogeological investigation is essential for assessing groundwater conditions, predicting inflows, and preventing inundation hazards in mines. It involves systematic collection of geological, hydrological, and hydro-chemical data. The investigation includes installing piezometers, conducting pumping tests, and preparing groundwater contour maps. Parameters like permeability, transmissivity, and storativity are determined. DGMS (MMR Reg. 244) and IBM guidelines mandate these studies before any new project or expansion. The final report includes inflow estimation, risk mapping, and preventive recommendations, ensuring safe mine planning and environmental compliance.
🎯 Test Your Knowledge: 25 MCQs
Q1. Hydrogeology deals with:
Q2. DGMS requires hydrogeological investigation before:
Q3. Piezometer is used to measure:
Q4. The unit of hydraulic conductivity is:
Q5. MODFLOW is used for:
Q6. Transmissivity (T) = ?
Q7. DGMS Circular on Hydrogeology was issued in:
Q8. IBM Manual on Hydrogeology (2020) focuses on:
Q9. Storativity is:
Q10. Water inflow rate into mine workings depends on:
Q11. Which tool records continuous water levels?
Q12. DGMS Reg. 244 relates to:
Q13. Pumping test helps determine:
Q14. Rainfall–runoff correlation helps in:
Q15. IBM = ?
Q16. Groundwater table maps are called:
Q17. Piezometer casing pipe is usually made of:
Q18. Seepage inflow is more likely in:
Q19. Data loggers help in:
Q20. Hydraulic gradient controls:
Q21. Groundwater modeling aids in:
Q22. Hydrogeological risk is higher in:
Q23. Inflow prediction helps in:
Q24. IBM guidelines are part of:
Q25. The main purpose of hydrogeological study is:
Prepare for DGMS Exams with Confidence!
Join Online Mining Exam – India’s 1st Online Mining Academy for DGMS Hydrogeology Notes, 5000+ MCQs, and Live Tests.
Download Notes & Practice Now!Call/WhatsApp: 9971114020
Launch your Graphy