Economy Zigong

old salt wells in zigong



boiling brine pure salt

salt once 1 of major sources of revenue china. give idea of how money generated salt in china - after fall of last emperor, republic of china under sun yat-sen secured loans based upon revenues of chinese salt administration (the government agency in charge of taxation on salt). chief inspector of administration stated best salt in china produced salt wells of sichuan . best salt wells in sichuan in ziliujing district, zigong.

the people of zigong have been drilling in area salt since before han dynasty (76-88 a.d.) extract salt brine. historian estimates china has been active in producing salt since 6000 bc. brine aquifers in area have salinity of @ least 50 grams per liter. classical method of drilling , production following: drilling rig erected , borehole drilled using drilling bit , rope. brine extracted dropping long tube down borehole. membrane valve captures brine retrieval on surface. once brine retrieved s piped flat pans boiling. in boiling process water , crushed yellow soybean added. soybean absorbs impurities in salt. once boiled, yellow layer formed - scraped off leaving absolutely pure salt. salt medium grain salt different size flakes have strong , unique salt taste. salt has no additives clump. locals use grains of rice in salt keep salt clumping.

early methods of brine salt production involved digging large pits in earth (other parts of china used evaporation method). later methods involved innovative drilling , retrieval methods. unexpected byproduct of drilling , resulting wells natural gas. since natural gas didn t have uses today, channeled pipes , used onsite boil brine , extract salt. salt zigong produced rich in taste , served emperor of china tribute. people of zigong believe taste superior popular french sea salts such fleur de sel.

salt production via boreholes once prevalent in entire sichuan area - several factors (war, rebellion, taxes, wells drying up) zigong became center of production. salt wells in zigong deeper , had better brine salinity - making better yields in salt extraction process. method in boreholes drilled significant. in 1835, world s (at time) deepest drilled reaching 3,300 feet (compared publicised in pennsylvania @ 69.5 feet). wealthy families of sichuan city of jingyan invented deep percussion drilling techniques used in zigong - 400 years before europeans. miners of zigong refined techniques of deep borehole drilling. later, europeans copied , further refined percussion drilling methods - effects can seen in modern drilling rig used oil , water.

salt became engine of commerce , wealth zigong. there cheaper methods salt production, start borehole cost 3,000 pieces of silver, transportation cost sichuan valley negated cheaper production methods (as involved sea water). zigong located in central chinese sichuan province, large basin, surrounded mountains on 3 sides , therefore isolated. before refrigeration available salt key chemical used in preserving vegetables, meat, , fish. because of factors mentioned above (war, wells drying up, , rebellion) zigong became significant supplier of salt sichuan province until 1930s. in 1892, miners discovered vein of rocksalt feeds zigongs aquifers. in 1946, drilled rotary drillbit. ancient percussion drilling methods became obsolete , of drilling rigs torn down due decay. today, 1 traditional salt still exists, shenhai well, tribute workers , industry. shenhai (bore depth: 1,001.4 meters/4,400 feet) still operates using older manual methods of pumping , boiling. salt used pickling or canning - , makes important ingredient sichuan style pickles (which local favorite). in modern day, zigong primary source natural gas, coal, , inorganic chemical production in addition salt.