In mineral processing, which equipment is classified as a coarse crusher because it handles large feed sizes and performs primary crushing before secondary reduction stages?

Introduction / Context:
The first stage of comminution in mining and process engineering is primary crushing. A coarse crusher must accept very large lumps, reduce them to manageable sizes, and deliver steady throughput to downstream secondary crushers or mills.

Given Data / Assumptions:

• The question asks for a “coarse crusher.”
• We compare typical duties of common crushers and mills.
• No numerical calculation is required; this is a machinery selection concept.

Concept / Approach:
Primary (coarse) crushers include jaw and gyratory crushers. They are designed for high capacity and large feed openings. Secondary and tertiary crushers or grinding mills (rolls, ball, tube) work on already-reduced feed and are not considered coarse crushers in standard flowsheets.

Step-by-Step Solution:
List the options and map them to duty: gyratory (primary), roll crushers (secondary/tertiary), tube and ball mills (grinding, not crushing).Confirm gyratory crushers accept the largest feed and deliver coarse product.Select gyratory crusher as the coarse crusher.

Verification / Alternative check:
Classic plant layouts show a primary gyratory or jaw ahead of secondary cone/rolls and ball or SAG mills; this confirms the classification.

Why Other Options Are Wrong:
Smooth roll: mainly secondary, produces finer, controlled product.Toothed roll: medium-duty primary for soft coal, but not general-purpose coarse crusher for hard rock.Tube/Ball mill: grinding devices, not crushers.

Common Pitfalls:
Confusing “primary” for coal (where toothed rolls may be used) with hard-ore practice, where gyratory dominates.

Final Answer:
Gyratory crusher