For tunnelling in hard rock, arrange the standard operations in the correct sequence: (1) Removing ground water, (2) Loading holes and firing explosives, (3) Setting up and drilling, (4) Grouting and lining, (5) Removing muck, (6) Ventilation and removing explosion dust.

Introduction / Context:
Tunnel excavation in hard rock follows a disciplined cycle to ensure safety, productivity, and quality of the finished lining. The cycle begins with drilling, continues through blasting and ventilation, and ends with muck removal and subsequent support or lining. Recognizing the proper order helps in planning resources, equipment, and shift operations.

Given Data / Assumptions:

• Operations are numbered 1 through 6 with standard meanings.
• We assume conventional drill-and-blast tunnelling in hard rock.
• Dewatering and grouting/lining occur after the immediate excavation cycle steps when needed.

Concept / Approach:

The basic excavation cycle is: set up and drill the blast holes, charge and fire, ventilate fumes and dust, muck out, then proceed with auxiliary works like water control and final lining. This produces a logical, safe progression minimizing exposure to fumes and ensuring clear access for mucking equipment.

Step-by-Step Solution:

Verification / Alternative check:

Industry practice and many method statements document this exact flow, with minor variations depending on site constraints, confirming option '3 2 6 5 1 4'.

Why Other Options Are Wrong:

• Sequences starting with lining or grouting before excavation are illogical.
• Ventilation must precede mucking to ensure safety.
• Random orders disrupt safe access and productivity.

Common Pitfalls:

• Entering the heading before adequate ventilation.
• Attempting auxiliary works before clearing muck and stabilizing the face.

Final Answer:

3 2 6 5 1 4