21231 - Stone Mining and Quarrying

The North American Industry Classification System (NAICS) plays a crucial role in organizing industries for government contracting, economic analysis, and business development. One key code that forms the backbone of construction materials supply is NAICS code 21231 – Stone Mining and Quarrying. This industry fuels a wide array of projects, from towering office buildings to local landscaping efforts, by providing essential raw materials extracted directly from the earth.

What is NAICS Code 21231 – Stone Mining and Quarrying?

NAICS Code 21231 is assigned to establishments involved in the extraction and processing of natural stone materials. This includes dimension stone — large blocks or slabs cut or shaped for building and ornamental use — as well as crushed and broken stone, riprap, sand, gravel, and clay. These materials serve as foundational elements in construction, road building, landscaping, and various other industrial applications.

Sector Overview

• Sector: Mining, Quarrying, and Oil and Gas Extraction
• Industry Group: Mining (except Oil and Gas)
• Subsector: Nonmetallic Mineral Mining and Quarrying

Stone Mining and Quarrying falls within this sector because it involves the physical extraction of mineral-based raw materials from the earth, distinguishing it from manufacturing or distribution.

Typical Business Activities Under NAICS 21231

Businesses categorized under NAICS 21231 engage in various specialized activities including:

• Dimension Stone Quarrying: Extracting large blocks or slabs of granite, marble, limestone, sandstone, and other stone types used in monuments, building facades, countertops, and decorative elements.
• Crushed and Broken Stone Mining: Producing aggregates used in concrete mixtures, road construction, and rail ballast.
• Riprap Mining: Gathering large stones used to prevent erosion along embankments and shorelines.
• Sand and Gravel Mining: Extraction of sand and gravel for use in concrete, asphalt, and landscaping.

These operations often combine quarrying techniques with primary crushing and screening to deliver products tailored to specific construction or landscaping needs.

Size Standards for NAICS 21231 Eligibility

For government contracting and SBA loan purposes, the U.S. Small Business Administration (SBA) sets size standards based on either average annual receipts or number of employees. For NAICS 21231:

• Size Standard:
  • Maximum of 500 employees OR
  • Maximum of $15 million average annual receipts

This size standard helps determine eligibility for small business programs and federal contracts.

Examples of Businesses Falling Under NAICS Code 21231

• Granite Ridge Stone Works: Specializes in dimension granite slab quarrying and custom cutting.
• Midwest Crushed Stone Inc.: Focused on crushed limestone mining for road construction.
• Lakeside Riprap & Gravel: Provides riprap and gravel extraction services for erosion control and landscaping.
• Coastal Sand & Stone Quarries: Extracts and processes a variety of sand and stone products for coastal infrastructure.

NAICS Code 21231 – Stone Mining and Quarrying | Code Details Table

Attribute	Details
NAICS Code	21231
Industry Title	Stone Mining and Quarrying
Sector	Mining, Quarrying, and Oil and Gas Extraction
Subsector	Nonmetallic Mineral Mining and Quarrying
Description	Extraction of dimension stone, crushed stone, riprap, sand, gravel, and clay
Primary Activities	Dimension stone quarrying, crushed stone mining, riprap and sand & gravel mining
Size Standard (SBA)	500 employees or $15 million average annual receipts

Frequently Asked Questions (FAQs)

What types of stone are included in NAICS 21231?

This NAICS covers a broad range of natural stone including granite, marble, limestone, sandstone, and other dimension stones, plus crushed stone aggregates, riprap, sand, and gravel.

How does NAICS 21231 differ from other mining codes?

Unlike metal mining or oil/gas extraction, 21231 focuses on nonmetallic minerals primarily used in construction and landscaping materials.

Can small businesses qualify under this NAICS code for government contracts?

Yes. To qualify as a small business under federal procurement programs, companies must meet the size standard of no more than 500 employees or $15 million average annual receipts.

What industries rely on stone mining and quarrying products?

Key beneficiary industries include construction, road and infrastructure development, landscaping, and environmental erosion control.

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With infrastructure and construction projects constantly underway across North America, NAICS Code 21231 – Stone Mining and Quarrying represents a vital industry sector with numerous business and government contracting opportunities. Understanding the classification, scope, and requirements can help businesses position themselves successfully and tap into ongoing demand for natural stone and aggregate materials.