Method for the preparation of rock specimens for laboratory testing
1979 Edition

Overview of Scope and Measurement Limits in IS 9179

Scope Highlights (Clause 7.4):

• Specimen surfaces, especially cylindrical ones, must be smooth and devoid of sharp irregularities.
• Straightness tolerance for specimens is ±0.3 mm over their length.
• Diameter variation in cylindrical specimens should not exceed ±0.2 mm.

Measurement Tolerances Overview

Additional Guidelines:

• Use comparators (Clause 2.6) for final dimension verification.
• Handle specimens with gloves to prevent contamination (Clause 4.2).
• The standard integrates Indian field requirements with international norms.

flowchart TD
    A[Specimen Preparation] --> B[Surface Smoothness Inspection]
    B --> C{Is surface smooth?}
    C -- Yes --> D[Straightness Verification (±0.3 mm)]
    C -- No --> E[Surface Rework]
    D --> F{Diameter Variation ≤ 0.2 mm?}
    F -- Yes --> G[Accept Specimen]
    F -- No --> H[Reject or Reprocess Specimen]

This approach ensures specimen quality suitable for IS 9179-compliant testing.

Definitions and Tolerances in IS 9179 (Clause 7.4)

• Surface Requirements:

  • Cylindrical specimens must have smooth surfaces free from abrupt irregularities.
  • Straightness along specimen length must remain within ±0.3 mm.

• Dimensional Limits:

  • Diameter variation along length cannot exceed ±0.2 mm.

Summary Table: Dimensional Tolerances

Practical Notes:

• Maintaining these tolerances is vital for accurate mechanical test results.
• Smooth surfaces reduce stress concentration, preventing premature specimen failure.

flowchart LR
    A[Specimen Preparation] --> B{Inspect Surface}
    B -->|Smooth & No Flaws| C[Proceed]
    B -->|Flaws Present| D[Rework Surface]
    C --> E{Check Dimensions}
    E -->|Diameter ≤ 0.2 mm variation| F[Accept Specimen]
    E -->|Diameter > 0.2 mm| D
    E -->|Straightness ≤ 0.3 mm| F
    E -->|Straightness > 0.3 mm| D

Refer to full IS 9179 text and associated testing standards for comprehensive procedures.

Guidelines for Specimen Collection and Storage in IS 9179

Essential Requirements:

• Moisture Protection (Clause 3.2):

  • Immediately apply wax coating after sample retrieval to prevent moisture loss.
  • Transport specimens in wooden containers filled with sawdust to cushion and retain moisture.
  • Store specimens in shaded environments, avoiding direct sunlight and extreme humidity or temperature changes.

• Contamination Prevention (Clauses 4.1 & 4.2):

  • Always wear gloves during handling to prevent contamination.
  • Place specimens on clean, dry surfaces exclusively.
  • If contaminated, clean specimens by soaking in solvents such as benzene or acetone, then rinse with clean water.

• Dimension Verification (Clause 2.6):

  • Use comparators to accurately confirm final specimen dimensions.

Handling Summary Table

flowchart LR
    A[Sample Collection] --> B[Immediate Waxing]
    B --> C[Transport in Wooden Box with Sawdust]
    C --> D[Store in Shade, Controlled Environment]
    D --> E[Gloved Handling]
    E --> F{Is Specimen Contaminated?}
    F -- Yes --> G[Soak in Solvent + Rinse]
    F -- No --> H[Dimension Check Using Comparator]

These steps maintain specimen quality per IS 9179 standards.

IS 9179 Contamination Prevention Protocols

• Handling Practices: Always use gloves to prevent contamination of specimen surfaces (Clause 4.2).
• Surface Placement: Position specimens only on clean, dry surfaces (Clause 4.2).
• Avoid Contact with Oils and Substances: Specimens must remain free from oils or other contaminants throughout preparation (Clause 4.1).
• Decontamination: If contamination occurs, soak specimens in benzene or acetone, followed by thorough washing with clean water (Clause 4.1).
• Moisture Sealing: Wax specimens immediately after collection to prevent moisture ingress (Clause 3.2).
• Transport and Storage: Use wooden boxes with sawdust during transport; store specimens in shaded, humidity- and temperature-controlled areas (Clause 3.2).
• Dimension Verification: Employ comparators for final dimensional checks ensuring no alteration due to contamination (Clause 2.6).

Summary Table: Contamination Prevention Actions

flowchart LR
    A[Specimen Collection] --> B[Wax Immediately]
    B --> C[Transport in Wooden Box with Sawdust]
    C --> D[Store in Shade with Stable Conditions]
    D --> E[Gloved Handling]
    E --> F[Place on Clean, Dry Surface]
    F --> G{Contamination Present?}
    G -- Yes --> H[Soak in Benzene/Acetone + Wash]
    G -- No --> I[Dimension Verification with Comparator]

Adhering to these ensures specimen integrity for accurate testing.

Dimensions and Shape Specifications in IS 9179

• Specimen Diameter (Clause 5.2):

  • Must be at least 10 times the maximum grain size.
  • Preferably 20 times the maximum grain size.
  • Absolute minimum diameter: 35 mm with relaxed tolerances.
  • Recommended minimum diameter: 45 mm.

• End Surface Criteria (Clause 7.3):

  • Flatness tolerance of ends: 0.05 mm.
  • Parallelism between ends: within 0.002 times the specimen diameter.
  • Perpendicularity of ends to the axis: within 0.001 radians (~3.5 arc minutes) or 0.05 mm for 45 mm diameter specimens.

Dimensional Summary Table

Notes:

• Use gloves and maintain clean surfaces to avoid contamination during preparation (Clause 4.2).
• Specimen geometry must comply with relevant IS testing protocols.

flowchart TD
    A[Select Rock Sample] --> B[Measure Max Grain Size]
    B --> C{Diameter ≥ 10 × Grain Size?}
    C -- Yes --> D{Diameter ≥ 45 mm?}
    C -- No --> E[Increase Diameter or Reject Sample]
    D -- Yes --> F[Prepare and Finish Specimen Ends]
    D -- No --> G[Apply Reduced Tolerances]
    F --> H[Verify Flatness ≤ 0.05 mm]
    F --> I[Verify Parallelism ≤ 0.002D]
    F --> J[Verify Perpendicularity ≤ 0.001 rad]

IS 9179: Procedures for Cutting and Grinding Rock Specimens

Cutting (Clause 6.2)

• Employ sawing methods for initial specimen shaping.
• Ensure minimal edge damage during cutting.

Grinding Abrasives (Clause 6.5.3)

• Use Silicon Carbide-Aluminium Oxide abrasive compounds.
• Recommended grit size ranges between 80 and 220.
• Apply abrasives in water to maintain cooling and avoid overheating.

Edge Grinding (Clause 6.3.2)

• Utilize tool post grinders or fixed diamond points.
• Maintain slow rotation speed (~300 rpm) to prevent specimen damage.

Surface Grinding (Clause 6.4)

• Applied on larger flat surfaces for prismatic specimens.
• Achieves improved dimensional precision.

Process Summary Table

flowchart LR
    A[Sawing] --> B[Edge Grinding]
    B --> C[Surface Grinding]
    C --> D[Specimens Within Tolerance]

Note: Continuous cooling during grinding is crucial to prevent heat damage and maintain dimensional accuracy.

Measurement and Tolerance Criteria in IS 9179 (Clause 7)

• Surface Quality: Cylindrical specimen surfaces must be smooth, free from sharp irregularities, and straight within ±0.3 mm.

• Dimensional Variation: Diameter must not fluctuate more than 0.2 mm along specimen length.

• Measurement Instruments:

  • Use micrometers or vernier calipers during machining.
  • Employ comparators for final tolerance confirmation.
  • Final measurements accurate to 0.1 mm.

• Grinding Medium: Silicon Carbide-Aluminium Oxide abrasives (80 to 220 grit) in water to prevent overheating during grinding (Clause 6.5.3).

Tolerance Summary Table

flowchart TD
    A[Specimen Machining] --> B[Measure with Micrometer/Vernier]
    B --> C{Within Tolerances?}
    C -- Yes --> D[Final Measurement with Comparator]
    C -- No --> E[Re-machine Specimen]
    D --> F[Check Surface and Diameter Tolerances]
    F --> G{Pass?}
    G -- Yes --> H[Accept Specimen]
    G -- No --> E

This ensures specimens comply with IS 9179 for precise and dependable testing.

Cleaning Protocols for Contaminated Rock Samples as per IS 9179

Key Points (Clause 4.1 & 4.2):

• Specimens must remain free of oils or contaminants throughout preparation.
• Contaminated specimens should be immersed in solvents such as benzene or acetone.
• After soaking, specimens must be thoroughly rinsed with clean water to eliminate solvent residues.
• Use gloves when handling and place specimens only on clean, dry surfaces to avoid further contamination.

Handling and Storage (Clause 3.2):

• Wax specimens immediately after collection for moisture protection.
• Transport using wooden boxes filled with sawdust to prevent damage.
• Store specimens in shaded areas with controlled humidity and temperature.

Summary Table

flowchart TD
    A[Specimen Collection] --> B[Wax for Moisture Protection]
    B --> C[Transport in Wooden Box with Sawdust]
    C --> D[Store in Shaded, Controlled Environment]
    D --> E{Is Specimen Contaminated?}
    E -- Yes --> F[Soak in Solvent]
    F --> G[Wash with Clean Water]
    E -- No --> H[Handle with Gloves]
    H --> I[Place on Clean, Dry Surface]

These practices maintain sample integrity for IS 9179-compliant testing.

Essential Equipment and Tools as per IS 9179

Surface and Dimensional Requirements (Clause 7.4)

• Specimen surfaces must be smooth and free of abrupt irregularities.
• Straightness tolerance: ≤ 0.3 mm deviation.
• Diameter variation must not exceed 0.2 mm along specimen length.

Drilling Apparatus (Clause 2.1)

• Employ a heavy, rigid laboratory coring drill.
• Required features:
  • Secure clamping mechanism.
  • Minimum drill travel of 150 mm; preferably 250–300 mm.
  • Constant force hydraulic feed system preferred.
  • Electrical overload protection.

Sawing and Cutting Devices (Clause 6.2)

• Use precision saws ensuring clean cuts without specimen damage.

Lapping Machines (Clause 2.5)

• Use rotating iron discs or automatic lapping machines.
• Must include clamping fixtures.
• Capable of processing multiple specimens simultaneously for smooth finishes.

Dimensional Tolerance Summary

Dimensional Control Diagram

graph LR
A[Specimen Surface] --> B[Smooth & Free from Irregularities]
B --> C[Straightness ≤ 0.3 mm]
C --> D[Diameter Variation ≤ 0.2 mm]

Note: Regular calibration and maintenance of all equipment are essential to maintain accuracy and repeatability in specimen preparation.

Reporting and Documentation Essentials in IS 9179

• Rounding Off Data: Final test results and calculations must be rounded according to IS 2-1960 guidelines on numerical rounding (Clause 0.4).

• Specimen Dimensional Reporting (Clause 7.4):

  • Surfaces must be smooth and free of abrupt irregularities.
  • Straightness within ±0.3 mm.
  • Diameter variation not exceeding 0.2 mm.

• Measurement Verification: Use comparators for final dimensional checks (Clause 2.6).

• Report Content:

  • Include all measured and computed values with proper rounding.
  • Document specimen preparation methods and dimensional tolerances.
  • Record equipment and procedures utilized.

Dimensional Tolerances Summary

For detailed rounding procedures, consult IS 2-1960.

flowchart TD
    A[Test or Analysis] --> B[Measurement]
    B --> C[Dimension Check]
    C --> D{Within Tolerances?}
    D -->|Yes| E[Record and Round Off per IS 2-1960]
    D -->|No| F[Re-prepare Specimen]
    E --> G[Prepare Test Report]

For further clarifications, contact the Central Laboratory in Sahibabad or other regional centers referenced in the standard.