Gravity stamp mill duty:\nA gravity stamp mill is primarily intended for which stage of crushing?

Introduction / Context:
Historic ore-processing circuits used gravity stamp mills to break mined rock before concentration. While modern plants rely on jaw and gyratory primaries, the role of stamp mills in early flowsheets remains a common exam reference and helps contextualize how equipment evolved.

Given Data / Assumptions:

• Stamp mills deliver heavy, repeated blows to break large lumps.
• Downstream stages provide finer reduction and concentration.

Concept / Approach:
The duty of a stamp mill is coarse breakage of run-of-mine ore into smaller fragments suitable for further grinding (e.g., in pans or ball mills). The mechanism is impact from falling stamps, comparable to primary crushing in today’s terminology. It is not suitable for fine or ultrafine grinding, which require sustained abrasion/attrition in mills.

Step-by-Step Solution:

Verification / Alternative check:
Classical gold circuit descriptions place stamp batteries ahead of amalgamation or milling, analogous to primary crushers today.

Why Other Options Are Wrong:

• Intermediate/fine/ultrafine: outside the practical range of stamp mills.
• Tertiary shaping: a modern VSI duty, not stamps.

Common Pitfalls:
Equating “impact” with “fine”; impact energy per particle depends on mass and control of collisions.

Final Answer:
Primary crushing