The Sea of Death's Mineral Heart
Lop Nur is a vast, salt-encrusted playa at the eastern end of the Tarim Basin, a hyper-arid region that receives less than 32 millimeters of precipitation annually. For millennia, this was the terminal basin for the Tarim River, creating a huge and shifting salt lake that once covered over 10,000 square kilometers. Tectonic subsidence created the depression, which trapped water and dissolved minerals from the surrounding mountains. The lake's location shifted over centuries, earning it the name the "Wandering Lake". By 1972, upstream dam construction and irrigation projects had completely severed its water supply, causing the lake to evaporate entirely. What remains is a desolate salt flat, with a salt crust ranging from 30 to 100 centimeters thick, covering an area of about 10,000 square kilometers.
From Mushroom Clouds to Fertilizer Mines
This remote region was selected as China's primary nuclear weapons test site. The Lop Nur Nuclear Test Base was established on October 16, 1959. Between 1964 and 1996, a total of 45 atmospheric and underground nuclear tests were conducted here. The first test, a 22-kiloton uranium fission bomb codenamed "Project 596," was detonated on October 16, 1964, making China the world's fifth nuclear power. The final test occurred on July 29, 1996, just before China signed the Comprehensive Nuclear-Test-Ban Treaty. After the moratorium, geological surveys in the mid-1990s revealed that beneath the salt crust lay one of the world's largest deposits of potash, a potassium salt important for manufacturing fertilizer. The estimated reserves of potassium chloride exceed 500 million tonnes.
Harvesting Ancient Brine
Commercial mining began in 2000, managed by the state-owned SDIC Xinjiang Lop Nur Potash Co., Ltd. The potassium is not in a solid ore but is dissolved in a highly concentrated brine, trapped within layers of sediment deep underground. This brine is pumped to the surface into a vast network of solar evaporation ponds that are visible from space. Water is dyed blue to increase heat absorption from the sun, which accelerates evaporation. As the water evaporates, the potassium salts crystallize and are harvested. This operation is now the largest single-site producer of potassium sulfate in the world, with an annual production capacity of 1.6 million tons. To support this massive industrial undertaking in such a remote location, a 375-kilometer railway connecting Lop Nur to the city of Hami was completed in 2012.