dilving

Dilving was a gravity separation method used in tin mining to concentrate ore by shaking a sieve submerged in water. The principle was simple: tin ore particles, being denser than gangue (waste rock), would settle and remain in the sieve while lighter material washed away through the mesh. This process was practised in cornish and devon tin mines where alluvial and eluvial deposits provided suitable ore grades for treatment.

The mechanics relied on the sieve holder standing in a trough or shallow stream. The worker would raise and lower the sieve frame rhythmically, typically wooden with a wire or woven metal mesh base, allowing the water to carry finer waste particles over the edge while heavier tin particles lodged against the mesh. The submerged action reduced dust and made the work less arduous than dry screening, though it required a reliable water supply on site.

Why dilving became obsolete

Dilving fell out of use as ore grades declined and mines worked deeper deposits with higher clay and fine particle content. The process was slow and labour intensive compared to mechanical jigs and shaking tables that became standard in the 19th century. These powered alternatives offered better recovery rates and could handle finer particles that dilving could not retain effectively.

The term itself is now confined to mining history texts and archaeological records of tin working sites. It appears in 16th and 17th century mining manuals and accounts of cornish mining practice, but the word has no modern equivalent in contemporary mineral processing because the underlying technique has no current industrial application. Understanding dilving matters mainly to those reconstructing historical mining operations or studying the evolution of ore dressing technology.