A brine well reaches natural salt water, or salt beds that can be dissolved by pumped-in fresh water, through a lined shaft that keeps fresh water and cave-ins out, with the brine lifted by bucket, rope or pump. A litre of saturated brine holds about 0.32 kg of salt, so a well yielding only about 4 to 12 litres a day of strong brine would meet the annual salt needs of 100 people, which makes the strength and purity of the brine more important than the volume.
Part of Salt Production & Sourcing
A brine well is a shaft or borehole sunk to a salt-bearing layer so that natural brine, or brine made by dissolving the layer in injected water, can be lifted and boiled down.
How The Parent Describes It
The parent’s method: drill or dig a well into the salt layer, pump in fresh water, let the water dissolve salt to make brine, pump the brine up, then evaporate it by sun or fire. It adds that this needs knowledge of local geology: ask elderly residents, check old geological surveys, or follow animal trails. Some salt layers already hold natural brine, in which case the well only has to reach it.
How Little Brine You Need
A litre of saturated brine weighs about 1.197 kg and is 26.4% salt (recalled density), so it holds
1.197 × 0.264 = 0.316 kg of salt.
For the salt article’s annual use of 1,040-1,870 lbs (472-848 kg):
- low: 472 ÷ 0.316 = 1,494 litres a year, about 4.1 litres a day
- high: 848 ÷ 0.316 = 2,683 litres a year, about 7.4 litres a day
Using the salt article’s headline figure of 1,500-3,000 lbs instead (680-1,361 kg), the totals are 2,153-4,307 litres a year, or about 5.9-11.8 litres a day. Across the two budgets that is roughly 4 to 12 litres a day for 100 people, each litre carrying about 0.32 kg of salt. So a modest, strong, steady supply is enough; what matters is that it stays strong and clean. The weight to lift is also higher than for water: about 3.16 litres, or 3.8 kg, of saturated brine for each kilogram of salt.
What Goes Wrong With A Brine Well
- Fresh water leaks in through the upper walls and dilutes the brine, wasting fuel. The upper shaft is lined and sealed (Well Lining: Stabilizing Well Walls describes dry-stacked stone and other liners).
- The shaft caves in. Salt-bearing ground can be weak or run with water; line the shaft as you go, as for a water well (Well Digging: Hand-Dug Water Wells).
- Dissolving the layer too fast by pumping in fresh water carves cavities that can collapse and subside the ground above. Take brine slowly and watch the surface.
- Brine from near oil or gas can carry hydrocarbons, gas and other contaminants.
- The brine is heavy and corrosive. Rope, buckets and pumps of iron rust; use materials that tolerate salt (Water Lifting lists lifting devices).
What You Need
- Knowledge of where salt is: old records, springs, licks and local elders
- Digging or drilling tools, shaft lining material, and a windlass or pump
- A tank to settle the brine and keep it covered
- A way to measure brine strength: evaporate a measured volume and weigh the residue
Method: Sink And Run A Brine Well
Step 1: Choose a site with signs of salt: a spring, lick or known layer.
Step 2: Dig or bore the shaft in stages, lining each stage before going deeper.
Step 3: Seal the upper lining against fresh water; leave the lower part open to the brine.
Step 4: Lift a sample, settle it and measure its strength.
Step 5: Pump or lift at a steady, modest rate and re-measure each month.
Common Mistakes
- Going deep before lining.
- Using galvanised or zinc-coated pipe, which the brine attacks.
- Pumping hard and drawing in fresh water or collapsing a cavity.
- Never retesting the strength.
Safety
A well shaft can kill the people who dig and enter it
Shafts collapse, and an open shaft is a fall hazard. Bad air, including oxygen-poor air and in some regions gas from the salt-bearing ground, can fill a shaft; never enter one to retrieve a person or a tool, and never lower people into it without lining, a rope, a second person at the top and a way to ventilate it. Brine with an oily sheen, a fuel smell, or from near oil or gas workings may carry hydrocarbons and radioactive minerals and must not be used for food.
What’s Next
- Learn next: Brine Boiling — turning the brine into salt
- Combine with: Salt springs and licks — brine that reaches the surface unaided