Gyratory vs jaw crushers: which statement is true of gyratory crushers compared to reciprocating jaw crushers?

Introduction / Context:
Gyratory and jaw crushers are both primary crushers, but their kinematics and continuous vs. intermittent action differ, affecting capacity and power draw.

Given Data / Assumptions:

• Standard large primary machines handling hard rock.
• Comparison focuses on capacity and operation mode.

Concept / Approach:
Gyratories crush continuously as the mantle gyrates within the concave, offering higher capacities for a given discharge area. Jaw crushers crush intermittently as the movable jaw oscillates, leading to lower throughput for the same gape and a more pulsating power draw.

Step-by-Step Solution:
Identify operation mode: gyratory = continuous; jaw = intermittent.Capacity implication: continuous action yields greater capacity per discharge area in gyratories.Therefore, the true statement is option (a).

Verification / Alternative check:
Manufacturer catalogs show higher tph ratings for gyratories than comparable jaw units at similar open-side settings.

Why Other Options Are Wrong:
(b) Intermittent crushing describes jaws, not gyratories.(c) Gyratories are well suited for coarse, high-capacity duties.(d) Gyratories have steadier, not less steady, power consumption due to continuous crushing.

Common Pitfalls:
Judging capacity solely by gape without considering continuous vs. intermittent action and chamber profile.

Final Answer:
They have greater capacity per unit of discharge area.