🎓 Lesson 3
D2
Legal Duty of Care and Due Diligence in Practice
Duty of care means you must take reasonable steps to protect people and the environment from harm caused by your blasting work, and due diligence means you can prove you did everything a competent professional would do to meet that duty.
🎯 Learning Objectives
- ✓ Explain the legal distinction between duty of care and due diligence using Australian WHS Act and Canadian OHS Regulations as comparative frameworks
- ✓ Analyze a blast design report to identify gaps in due diligence documentation (e.g., missing risk register entries, unverified assumptions, or absent stakeholder consultation records)
- ✓ Apply the 'Reasonably Practicable' test to evaluate whether a proposed mitigation measure satisfies duty of care obligations under ISO 45001 and national mining regulations
- ✓ Design a due diligence evidence checklist aligned with Mine Safety and Health Administration (MSHA) Part 46/47 and ICMM Due Diligence Guidance
📖 Why This Matters
In 2022, a major Australian open-pit mine faced $3.2M in penalties—not for a blast failure, but because its blast risk assessment lacked dated sign-offs, omitted vibration monitoring calibration records, and failed to document consultation with nearby Indigenous landholders. Duty of care and due diligence aren’t abstract legal concepts—they’re operational lifelines. A single undocumented assumption in a blast design can trigger regulatory prosecution, civil liability, project delays, or loss of social licence. This lesson bridges engineering practice and legal accountability: you won’t just learn *how* to blast safely—you’ll learn *how to prove* you did.
📘 Core Principles
Duty of care arises automatically under common law and statutes (e.g., Australia’s Work Health and Safety Act 2011, South Africa’s MHSA 1996, USA’s MSHA regulations). It applies vertically (engineer → workers), horizontally (engineer → neighbouring landowners), and intergenerationally (engineer → future environmental conditions). Due diligence is the affirmative defence: it requires demonstrable effort—not perfection—to eliminate or minimise foreseeable risks. Three pillars define robust due diligence: (1) Knowledge (awareness of hazards, standards, and site-specific context), (2) Action (implementation of hierarchy-of-controls-aligned measures), and (3) Verification (auditable records: signed checklists, calibrated instrument logs, meeting minutes, revision-controlled reports). Critically, ‘reasonably practicable’ balances risk severity and likelihood against time, cost, and technical feasibility—never a blanket exemption for budget or schedule constraints.
📐 The Reasonably Practicable Test
While not a mathematical formula per se, regulators apply a structured decision framework to assess whether duty of care was met. This test quantifies proportionality between risk and response—and is explicitly codified in Section 18 of Australia’s WHS Act and Clause 5.3 of ISO 45001:2018. Engineers must document their application of this test when selecting controls.
💡 Worked Example
Problem: A blast near a heritage-listed aqueduct poses moderate risk of ground vibration damage (likelihood = unlikely, consequence = major). Available control: install real-time seismographs + pre-blast structural survey ($18,500; 3 days). Alternative: rely on historical peak particle velocity (PPV) models only ($0; immediate).
1.
Step 1: Assign risk rating using ISO 31000: Likelihood (2/5) × Consequence (4/5) = Risk Score 8/25 (moderate).
2.
Step 2: Evaluate control feasibility: Seismograph option costs <0.02% of project CAPEX, requires no production stoppage, and reduces risk score to 2/25 (low).
3.
Step 3: Apply statutory test: Cost is grossly disproportionate? No. Technical capability exists? Yes. Time impact negligible? Yes. Therefore, seismograph + survey is *reasonably practicable*—omitting it breaches duty of care.
Answer:
The result is a legally defensible requirement to implement the $18,500 control. Failure to do so would invalidate due diligence, regardless of whether damage actually occurred.
🏗️ Real-World Application
In the 2019 Mount Arthur Coal case (NSW, Australia), an inspector prosecuted the blasting engineer for failing to verify drill hole deviation prior to firing—despite compliant burden/spacing ratios. The court accepted the engineer’s duty of care extended to confirming actual hole geometry (not just design), as deviation >15% alters energy coupling and increases flyrock risk. Due diligence was found lacking because: (1) no deviation log was attached to the blast record, (2) no procedure existed for reconciling as-drilled vs. as-designed holes, and (3) the engineer testified he ‘assumed’ drilling was accurate. The conviction underscored that due diligence requires *active verification*, not passive assumption—even for routine tasks.