Cobbing

Cobbing is the manual process of breaking apart raw asbestos ore with hammers, picks, or hand tools to separate fibrous asbestos from the surrounding rock. It was one of the earliest and dustiest stages of asbestos mining and milling, typically performed by workers sitting beside piles of ore. The work released enormous quantities of airborne fibers directly into the breathing zone of those performing it.

Origin

The term comes from the Old English and Cornish mining vocabulary, where "to cob" meant to break ore into smaller pieces with a hammer to hand-sort valuable mineral from waste rock. It was adopted into asbestos mining in the late 1800s as operations expanded in Quebec, South Africa, and Russia, and the practice persisted in some regions well into the twentieth century.

Significance in Asbestos Context

Cobbing produced some of the highest fiber exposures in the entire asbestos industry, and workers who did this job, or who worked nearby, frequently developed mesothelioma, asbestosis, and lung cancer decades later. For patients or family members who worked in or lived near asbestos mines (particularly the Thetford and Asbestos, Quebec operations, the Northern Cape crocidolite fields in South Africa, or the Libby, Montana vermiculite mine), a history of cobbing is powerful evidence of heavy direct exposure. Mining companies were aware by the 1930s that this hand-sorting process generated dangerous dust, yet many continued the practice without respiratory protection or dust controls, which is relevant to claims involving knowledge and corporate conduct.

Example Sentence

His mother described how, as a teenager in the 1940s, she had spent summers cobbing chrysotile ore at the mill, and the occupational historian flagged this as a likely source of her later mesothelioma.

Related Terms

Chrysotile, Crocidolite, Milling, Take-Home Exposure, Thetford Mines, Occupational Exposure History

Notes

• If you or a family member worked at an asbestos mine or mill, ask whether their job involved hand-sorting, breaking, or grading ore. These tasks may not appear by name in employment records but are central to exposure documentation.
• Preserve any photographs, letters, pay stubs, or union records that show the worker's job title, location, and dates; cobbing was often done by laborers, sorters, or "pickers" rather than under that exact name.
• Family members of cobbers should also be evaluated for take-home exposure, since fibers carried on clothing and hair caused mesothelioma in spouses and children.
• For cases involving Quebec mines, South African crocidolite fields, or Libby vermiculite, specialized occupational and industrial-hygiene experts can reconstruct cobbing-era exposures even when company records are incomplete.