Jigger

A gravity-based ore-dressing machine that separates crushed ore from waste rock by pulsating water through a perforated screen — a specific piece of dressing-floor equipment, distinct from the buddle or the kieve, used at the stage where crushed material still needed sorting by density before sale.

Historical usage

Jigging has been used in ore dressing for close to two centuries, with hand-jigging first practised in Cornwall before English miners carried the technique to other mining districts. By the 19th century, purpose-built jigger houses were a standard feature of a well-equipped dressing floor at larger metal mines across Britain, standing alongside the buddles, crushers and stone-breakers that made up the rest of a mine's surface processing plant.

How it worked

Crushed ore and water were fed into an open tank holding a jig screen — a perforated horizontal surface topped with a bed of coarse, heavy particles called ragging. A plunger, worked by hand or by machinery, pulsed water up and down through the bed, and as the ore moved across it, the densest particles — the valuable ore mineral — worked their way down through the ragging and screen to settle as concentrate at the bottom, while lighter waste rock stayed higher up and was washed away.

Why it was used

A jigger could treat large quantities of crushed ore quickly, was simple to build and operate compared with more elaborate dressing machinery, and worked reliably across a range of ore types and conditions — a straightforward, effective way to concentrate ore by density once crushing alone was no longer enough to separate it cleanly from waste.

Risks & limitations

Jigging worked well only where there was a real, exploitable difference in density between the target mineral and the surrounding waste rock; ore with only a marginal density contrast, or waste that closely resembled the ore in size and weight, was much harder to separate cleanly this way, and mines often ran jiggers alongside buddles and other dressing methods to catch what jigging alone missed.

Mines associated with this term

Included only where MineArchive's own research gives a reasonable evidential basis — not every mine where this might plausibly apply.

• Killhope Lead Mine — County Durham (well documented example)
  The mine's own recorded surface remains explicitly name a surviving jigger house.
• Nant-y-Garw Lead Mine — Powys (well documented example)
  The mine's own recorded workings explicitly describe a jigger among the dressing mill's equipment.
• Ystrad Einion Mine — Ceredigion (well documented example)
  The mine's own recorded surface remains explicitly name a surviving jigger building.

Sources

1. (secondary) Jigging — ScienceDirect Topics
2. (secondary) Jigging — 911 Metallurgist

Record created: 22 August 2026 · Last researched: 22 August 2026