Soil, water conservation mine rich seam of success

Worst hit area

The water and soil conservation work at the mine is a microcosm of the efforts made by the industry in the resource-rich area that straddles the provinces of Shanxi, Shaanxi and the Inner Mongolia autonomous region, which is a major contributor to the river's high concentration of sediment.

Resource exploitation means the area is the place worst hit by water and soil loss in the river basin, according to the local soil and water conservation supervision bureau.

Established in 1992 to tackle the problem, the bureau is the country's only soil and water conservation governmental body overseeing an area that falls under the jurisdiction of different provincial-level governments.

"About 70 percent of the major zones that contribute coarse sediment to the river in the basin are located in the area," according to the bureau, an affiliate of the Yellow River Conservancy Commission.

Analysis of monitoring data shows that 120 million metric tons of soil and solid waste were discarded by local coal mines from 1986 to 1994, which raised the sediment density in rivers by almost 27 percent.

With four major coalfields, the area boasts proven reserves of 280 billion tons, the bureau said. Meanwhile, local authorities have said there are currently more than 200 coal mines in Yulin alone.

All new major construction projects in the area have to roll out water and soil conservation measures, said Yu Quangang, the bureau's head. He added that in recent years all conservation plans for new projects have been inspected and approved by the body.

Yu said satellite remote sensing can help monitor any work, operations or activity that result in disturbance of the earth in an area as small as 0.1 hectare－about the size of two basketball courts.

This has saved bureau officials from visiting mines frequently to supervise work, he said.

In addition to traditional approaches to soil conservation, such as tree planting, authorities have also worked to transform traditional mining operations to prevent water and soil loss.

Experiments

At the Xiaobaodang underground coal mine, also in Shenmu, experiments have been carried out since August last year to identify an operating norm that would prevent leaks of shallow groundwater.

The efforts have borne fruit. Based on close monitoring of the leaks and underground fissures that can occur under a range of extraction methods, experts have formulated a preliminary operating norm. It provides specific suggestions about approaches under different conditions, including various thicknesses of impermeable layers of earth and rock that prevent water from penetrating the mining seams.

Xie Yongli, chief engineer of Xiaobaodang Coal, said the company drilled 23 observation wells to assist the monitoring work prompted by experiments.

As far as he is aware, prior to the experiments, there was no similar monitoring of the disturbance mining causes to underground water sources in China.

He said the company plans to apply the preliminary norm to new seams while carrying out more experiments and monitoring to further improve the system.

The company has also taken other measures to prevent soil erosion in the 220-sq-km mine.

For example, it has planted over 11,100 trees and invested 112.7 million yuan in water and soil conservation, a huge increase on the 32.2 million yuan cited in its initial plan.