The early caravans carried salt. Salt was deposited by evaporation in shallow seas, and the sad was then buried beneath sediments.
Salt is mined in Gulf Coast mines of Louisiana by drilling and blasting.
Salt is produced in San Francisco Bay by solar evaporation of bay water. Salt brine is evaporated under pressure with added heat. Solar evaporation involves the sun and wind. The Via Salaria was a Roman road used to transport salt to Rome from the Mediterranean Sea. Animals need sad to grow and reproduce at optimum rates.