Jixi, Hegang, Shuangyashan, and Qitaihe are four key coal mining cities in Heilongjiang Province. After decades of exploitation large areas of ground has begun to give way to subsidence affecting the lives of over 300,000 residents.
At 5 pm, on January 13, 2003, Yu Qingjun, an employee of the first integration exploration team of the Xing'an coal field, Hegang City, was in his house cooking with two others. Suddenly, the ground fell in and formed a 5m x 5m x 5m pit, tipping the three of them into it. Thanks to a speedy rescue, the three were all saved but suffered some injuries including bone fractures.
Just like the revolutionary work slogan, Production first, life second, the early years of coal mining was to be recklessly exploitative. City designs were forgotten, living areas spread out around mining areas without any thought of design, and miners and their families lived right on the top of the mines with some tower blocks right above the coalfields. Long time, large-scale mining and the lack of city programming lead to catastrophic and dangerous subsidence under the four cities.
Qitaihe City where the coal has been mined since 1958, has contributed 280 million tons of coal to the nation. To date, the city has sunk from 2.5 meters to 6.5 meters.
In Hegang City which contributed 550 million tons of coal to the country from her 41 mine layers, the underground subsidence area has enlarged to 63.73 square kilometers so far, recording a 30 meters subsidence depth, with the biggest fissure reaching 6 meters wide. The earth surface of the area has stayed in an unstable and deteriorating condition, with the city sinking at a speed of 130 cm a year.
Jixi City, after eight-plus years of exploitation, has hollowed out a 114 square kilometer subterran, with a surface area of 193 square kilometers. Yang Zhangwei, deputy director of the Subsidence Office of Jixi City, has said that mining interferes with machine balance and rock integration, whose layers have shifted and become distorted. More hollow space appears after mining, which leads to more subsidence. Houses are destroyed, as well as water pipelines, roads, bridges, and communication and dike facilities.
Realizing the seriousness of subsidence, the state's relevant departments have been trying to tackle the problem by issuing new rules and regulations. In 1990, Qitaihe City started its rehousing and subsidence control projects. By enforcing local moving and compensation regulations, buildings, schools, and urban infrastructure have been moved, rebuilt or buttressed according to the degrees of danger. As for some important buildings, the coal mine underneath them was reserved in order to maintain a solid foundation. Coal pillars were built to support villages and residences. New and safe housing blocks were constructed to adopt old residents.
In addition, the city carries on its research into subsidence, developing the only subsidence discipline in the country. An anti-sinking street was built in the sinking area, with the highest building there being six floors.
With help and financial aid from the state, Hegang and Jixi City are also making efforts to consolidate civil and public facilities.
However, the effect is far from sufficient. Peng Jinglei, from the subsidence-control research center of Qitaihe City said that the fund is not likely to produce great results quickly. Migration funds are short by 900 million yuan; control and rebuilding funds short of 600 million yuan. Another coal mine city, Shuangyashan, is working on the second stage of its subsidence control project, planning to invest 1400 million yuan, but still with a shortfall of 600 million.
Stringent funds and a sluggish control pace cannot match the spread of underground danger. The sinking area of Shuangyashan City has been raised thirty percent in the last four years, from 61 square kilometers in 1998 to 87 square kilometers in 2002.
Jixi City has only improved the condition of three of her mine fields, but more than ten others and 50,000 residents are still waiting for help. Hegang City has 720,000 square meters of damaged housing needing treatment. Some big fissures (more than one meter in width) were discovered in Nanshang, Fuli and Xing'an coal mines, causing many people, including livestock and vehicles to be trapped.
Subsidence control remains urgent work, said Ji Wanbin, the superintendent of the Sinking Research Center of Qitaihe City, and it needs to be speeded up and to have greater more scientific management.
(China.org.cn by Li Liangdu, September 23, 2003)
