Bonaire Salt Works History
In 1633, the Dutch took possession of Curacao, Bonaire and Aruba. The largest island, Curacao, emerged as a center of the notorious slave trade. Bonaire then became a plantation island belonging to the Dutch West Indies Company. It was during those early years that the first African slaves were forced to work, cutting dyewood and cultivating maize and harvesting solar salt. Grim reminders of those days still remain in the form of slave huts and salt pans which were laboriously constructed by hand. They are an important part of the island's heritage and have been left to stand mute testimony to Bonaire's repressive beginning.
Until 1816, ownership of Bonaire changed hands a number of times, finally being returned that year to the Dutch as a result of the Treaty of Paris. A small fort, Fort Oranje, was built to protect the island's main resource, salt. Salt was one commodity that Bonaire had in endless supply, although it took back breaking slave labor to produce it. In the early days of the industry, the most important use for salt was in the preservation of food, since refrigeration was still centuries away.
By 1837, Bonaire was a thriving center of salt production. The government, who by then controlled the industry, built four obelisks, each painted a different color, red, white, blue and orange (the colors of the Dutch Flag and the Royal House of Orange). They were erected strategically near areas of the salt lake. The idea was to signal ships where to pick up their cargoes of salt. A flag of the corresponding color was raised atop a flagpole, thus signalling the ship's captain where to drop anchor. Three of the obelisks can still be seen today.
The abolition of slavery in 1863 signaled an end to the era of exploitation of those first Bonaireans. It was almost a hundred years later that the salt industry was revitalized. Today it is a division of Cargill, Incorporated, one of the largest businesses in the world.
The Outdoor Solar Salt Mine
Solar salt is produced by the action of sun and wind on seawater. The water evaporates until the brine is so concentrated salt crystallizes on the floor of the ponds. Solar salt mines must be located in areas of low rainfall and high evaporation rates.
The following is the process in which salt is mined on Bonaire
Intake ponds
The Intake ponds are where the process starts. They are surrounded by short levees that separate them from the ocean and follow the couture of the shoreline. Seawater is let in to the intake ponds through cuts in the shoreline, and then it is then pumped from the intake ponds into the evaporation pools.
Traveling along the seashore you can see several seawater inlets and levees that were first built centuries ago. Some of the old windmill pumps that pumped the seawater can also be seen, but now days most of the pumps are electric.
Evaporation Ponds
Through natural evaporation, water is drawn out of these ponds, creating increasingly saline brines. The art of salt-making involves keeping minerals in solution (or liquid phase) while sodium chloride precipitates into its pure white crystals. The minerals stay in solution and are harvested after the salt has crystallized.
In Bonaire these evaporator ponds and the intake ponds that surround them are an important habitat for the Pink Flamingo, because the ponds are shallow - an average of 1.5 feet deep - it's easy for the Flamingos find a meal in the low to mid salinity ponds.
Evaporation Pond Distinctive Colors
Once the ponds reach a high salinity, the native fish and plants can no longer live, their prey, the organisms lower on the food chain, multiply. These are bacteria, sometimes referred to as blue-green algae. The most dominant, actually changes the color of its protoplasm. As the brines grow saltier, the algae darken and its orange hue transforms into a brilliant vermillion, coloring the brines the same vivid red.
Harvest
When the brine is fully saturated, it is called "pickle." At that point, the brine is holding as much salt as it can, and the salt begins to crystallize. The salt is harvested by scraping the crystals off the bottom of the pond and then transported to the Wash House.
Wash House
At the wash house, the salt is dumped into a saturated brine solution to wash off any impurities that might be stuck to the crystals. Because saturated brine is already carrying as much salt as it can hold, very little salt dissolves in the wash.
The harvested salt goes through a series of washers and augers. The cleaned salt is then dropped onto a conveyor belt with a distinctive, triangular frame and moved onto the salt stacks.
When the fresh salt is first placed on the stack, it is 99.5 percent pure. For a few days, the fresh salt retains the pinkish color of the "pickle" from which it evaporated. Within a week or two, however, it turns a dazzling white.
Salt from the stack is transported by conveyor belt to waiting ships, where it is transported for further processing.
In order to log as a find you must meet Earthcache guidelines and complete the following tasks.
At the posted coordinates you will be at a popular dive site on public land, you do not have to go onto the Cargill property to complete the tasks.
1. You must submit a photo with of yourself and your GPS with the salt stacks in the back ground attached to your log.
2. You must send us an e-mail us with the following information; number of salt stacks on your visit, estimate the height of tallest stack, and estimate how far the salt has to travel down the conveyor from the salt stacks to the awaiting ship.
Don't wait to log your find, post with a picture, send the e-mail. if there is a problem with your findings we will contact you.