Class Code 1624
Quarries; Excavation – Rock
Class 1624 covers rock quarrying and rock excavation operations in California — from open‑pit benching and drilling to on‑site crushing and loading. This classification matters because rock work carries high injury and loss potential; the approved pure premium rate is $3.618 per $100 of payroll (effective Sept 1, 2026).
What Class Code 1624 Covers
This classification applies to operations that remove, break, or excavate rock rather than loose earth: surface quarries, open‑pit rock excavation for aggregate, dimension stone extraction, and associated on‑site processing that is integral to the quarry (drilling, blasting, primary crushing and screening). Covered activities include drilling blast holes, scaling and bench maintenance, loading rock into haul trucks, operating face shovels/excavators and primary crushers, and managing overburden where rock removal predominates. It also includes onsite maintenance of quarry equipment and the work of licensed blasters, survey crews, and scale house personnel when employed directly by the quarry operator. Routine excavation of soft soils or trenching at a construction site that is not primarily rock removal is typically classified elsewhere.
Who It Applies To
- Surface rock quarry owners and operators (granite, limestone, trap rock, etc.)
- Aggregate producers with on‑site drilling, blasting, and crushing
- Contractors whose principal business is rock excavation and quarrying
- Licensed blasters and blast crew members employed by the quarry
- Heavy equipment operators and mechanics working on quarry equipment
Common Job Duties
- Drilling blast holes and preparing charges for blasting operations
- Conducting bench scaling, highwall inspections, and rock fall mitigation
- Operating excavators, face shovels, front‑end loaders, and haul trucks
- Loading, hauling, and dumping blasted rock to primary crushers
- Operating or servicing primary crushers, screens, and conveyors
- Performing preventative maintenance and repairs on heavy equipment
Common Injury Risks
Understanding the $3.618 Rate
The pure premium rate of $3.618 per $100 of payroll represents the expected cost of claims for this class per unit of payroll. To estimate the pure premium, divide payroll by 100 and multiply by 3.618; insurers then add expense loads, apply your employer experience modification, schedule credits/debits, and any deductible or retrospective adjustments to determine the final premium. Your actual rate is affected by claim history, payroll mix, job classifications, safety programs, and loss control measures.
Cal/OSHA Compliance Requirements
Quarry and rock excavation operations in California must comply with Cal/OSHA Construction and General Industry orders: excavation and trenching controls, benching and slope requirements, blasting safety (licensed blasters and blasting plans), and controls for respirable crystalline silica (exposure monitoring, engineering controls, and written silica plans). Employers must also implement hearing conservation, traffic safety for mobile equipment, lockout/tagout for crushers, and pre‑shift hazard assessments.
How Key HR Helps Employers Under Class Code 1624
A PEO like Key HR can help quarry operators control workers' comp costs through correct payroll classification, proactive loss control tailored to rock operations (blasting protocols, silica control, mobile equipment traffic plans), dedicated claims advocacy, and return‑to‑work programs to limit indemnity exposure. Key HR also provides training, on‑site loss control consultations, and access to pooled buying power and safety resources that smaller operators may not achieve on their own.
Get a QuoteFrequently Asked Questions
If I excavate rock for a construction job, does that put me in class 1624?
Not automatically. Classification depends on the contractor's principal business and payroll. Firms whose primary operations are rock quarrying or rock excavation are typically classed 1624; contractors who occasionally excavate rock as part of broader construction work are often classified under construction codes. Key HR can review your operations and payroll mix to determine the correct class.
What steps cut workers' comp costs for rock quarry operations?
Prioritize controls that reduce frequency and severity: implement a written silica control plan with dust suppression and monitoring, enforce PPE and hearing conservation, maintain and inspect benches and scaling procedures, require licensed blasters and formal blasting plans, provide equipment operator training, and run an early return‑to‑work program to limit lost‑time claims.
How do I calculate my pure premium from the $3.618 rate?
Take your total payroll for class 1624, divide by 100, then multiply by 3.618 to get the pure premium dollar amount. Example: $500,000 payroll → (500,000/100) × 3.618 = $18,090 pure premium before experience modification and insurer expense loads.
Quick Facts
- Class Code
- 1624
- Classification
- Quarries; Excavation – Rock
- Pure Premium Rate
- $3.618 / $100 payroll
- Effective Date
- September 1, 2026
- Source
- WCIRB Approved Filing
Manage Workers' Comp Through a PEO
Key HR provides pay-as-you-go workers' comp for California employers — no large deposits, no audits, better rates.
Get a Quoteor call (800) 922-4133Ready to Simplify Workers' Comp for Class Code 1624?
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