China's cultural heritage authorities have begun mapping and surveying the ruins of former "cave factories" in the mountains of the southwestern provinces, hoping to preserve these cradles of the country's military industries.

"This 180-meter long, 30-meter wide cave used to house China's leading producer of fuel pumps for fighter jets," said Chen Wenrong, a cultural heritage official, who is leading a survey of a clandestine workshop in an ethnic Miao village of Qianxi County of Guizhou Province.

The Honglin (Red Forest) Machinery Plant, founded in 1966, ran in secret in the craggy mountain and karst landscape for 28 years, before it was moved to the more populous Pingba County in central Guizhou in 1994.

Today, the plant employs 3,000 people and produces fuel pumps and spares for military and civil aircraft.

"It was a cradle of China's aviation industry, and piloted monopolistic enterprises' reform to survive in the market economy," said Zhang Bendai, who was assistant general manager of Honglin before retiring in the late 1990s.

One of the first workers at the cave plant, Zhang said he was delighted at the local cultural heritage authorities' plan. "These caves carry an important episode of China's modern history and should not be deserted."

Military workshops were built in at least 10 mountainous provinces in western China from 1965 to the late 1970s to protect them in times of war. In Guizhou Province alone, there were nearly 100 such plants.

In their heyday, these plants involved a total investment of 200 billion yuan and employed more than 4 million workers.

Fed by orders from a huge army, these factories were prosperous until the late 1970s, built a strong defence industry and gave rise to new industrial cities, including Mianyang and Panzhihua in Sichuan Province and Liupanshui in Guizhou.

In the early 1980s, the plants were called upon to adapt to the civil market for survival as the country cut its defense forces and military procurement.

By then, their secret locations had become an obstacle and they began moving out of the mountains after the late 1980s.

"Many of these abandoned caves have been damaged and may disappear altogether if not protected," said Zhang Yong, an official with the Guizhou Provincial Cultural Heritage Bureau.

Zhang said his organizations would work out a map of all former cave factories in Guizhou Province and keep a separate file for each site after the ongoing survey, which would take about five years.

"We hope to build some of these places into theme parks to boost tourism and increase local people's incomes," said Wang Hongguang, chief of the provincial cultural heritage bureau.

He cited the example of a national mining park in Tongren City of Guizhou, built on the ruins of what used to be China's largest mercury mine, which was exhausted in the 1990s. "The underground tunnels and mined out areas drew large crowds of tourists every year."

(Xinhua News Agency January 27, 2010)