ISO 8866:1991

Overview

ISO 8866:1991 - "Rotary core diamond drilling equipment - System C" defines the dimensional, material and tolerance requirements for a complete family of rotary core diamond drilling components designated as System C. System C is a distinct equipment family (not interchangeable with ISO systems A or B) characterized by a series of nesting hole sizes with small clearances between hole wall and equipment, allowing use of thin‑walled casing tubes. The standard covers equipment for drilling holes with outer bit diameters from 35 mm to 112 mm (core diameters ~21 mm to 92 mm).

Key topics and technical requirements

• Scope of equipment: single‑ and double‑tube core barrels (types M, DM, T, DT, DP), diamond core bits, reaming shells, core lifters and cases, core tubes and heads, drill rods and couplings, casing tubes and couplings.
• Material properties: minimum mechanical properties (tensile strength, yield stress and elongation) are specified for manufactured items. Example values in the standard include drill rods with a minimum tensile strength ≈ 690 N/mm², yield ≈ 490 N/mm² and elongation ≈ 12%; drill‑rod couplings at higher values (see standard table).
• Dimensions & tolerances: detailed nominal outside diameters, wall thicknesses and thread forms for each size (tables and figures). Main hole diameters covered: 35, 46, 59, 76, 93, 112 mm (outer bit D).
• Geometric tolerances: requirements for tube straightness and curvature are specified (e.g., maximum deviation from straightness typically 1:2000 of tube length for drill rods and core tubes <73 mm OD, 1:1200 for larger tubes; curvature over 250 mm end ≤ 0.5 mm).
• Designation rules: item names include nominal outside diameter and the letter C to denote System C; core barrel types are identified by letter codes.
• Drawings & figures: the standard contains many figures (threads, couplings, assembly diagrams) and a main dimensions table (Table 2) for production and inspection.

Applications and users

• Practical uses: specification, manufacture, inspection and procurement of diamond coring tooling for mineral exploration, geotechnical investigations, hydrogeological and mining site investigations where precision core recovery is required.
• Primary users:
  • Equipment manufacturers and component suppliers
  • Drill rig designers and service companies
  • Mining and exploration engineers specifying coring systems
  • Quality control and testing laboratories
  • Procurement and standards compliance teams

Related standards

• ISO 3551 and ISO 3552 (Systems A and B) - System C is intended to be applied in parallel but is not interchangeable with Systems A or B.
• Refer to ISO/TC 82 (Mining) outputs for related drilling equipment standards.

Keywords: ISO 8866, System C, rotary core diamond drilling equipment, core barrels, drill rods, casing tubes, reaming shells, drilling tolerances, mining standards, diamond coring.