Dozens of heavy-duty trucks were at work, busily transporting soil and rocks from an enormous pit. Just a few hundred meters away, where the debris had once lain, the land had not only been leveled, but crops had been planted, including oilseed rape and wheat.

New villages and houses have replaced cave dwellings in the Mu Us Desert in Yulin, Shaanxi province. [Photo/Xinhua]

Without prior knowledge, visitors would hardly know they were standing in a coal mine. No heaps of coal are visible, and the familiar black color can only be glimpsed occasionally at the pit's bottom because a large swath of the land is covered by crops.

Welcome to the Xiwan open pit coal mine, 60 kilometers from the Yellow River as it flows through Shaanxi province.

As China ramps up measures to harness the world's most heavily sediment-laden waterway, the mine, in Shenmu county, Yulin city, is just one example of efforts being made to improve soil and water conservation in the river basin.

A 250-hectare section that has been leveled and planted with crops accommodates surface soil removed to aid construction of the coal mine, which started in 2015.

"Covered by sand and dotted with a few patches of grass, the area was so barren it could hardly support any crops," said Lei Zhiyong, chief engineer of Shaanxi Shenyan Coal, the mine's operator.

Yulin is located in the area bordering the Mu Us Desert-one of China's four major deserts-and the Loess Plateau, which is blanketed by deep, fine, wind-blown soil. The Yellow River gets its name because of the amber water that appears as it picks up the sediment during its passage across the plateau.

In the river's lower reaches, sedimentary deposits have caused the riverbed to rise above the surrounding plain, making the section "a river above the ground".

Soil remediation measures-designed to cleanse and revitalize the land-were rolled out soon after construction of the mine started.

While leveling the area, Shaanxi Shenyan Coal invited experts from Northwest A& F University in Xianyang, Shaanxi, and the China University of Geosciences in Wuhan, capital of Hubei province, to analyze the soil's composition, Lei said.

Based on the analysis, crops were chosen for experimental cultivation, he added, pointing at a plot of oilseed rape. The plants are thinly scattered and mostly short, though some have blossomed, and Lei said efforts will be made to improve the soil and grow trees and crops.

Though the mine only went into production in July last year, remediation efforts have also been made across another 50-hectare site. So far, total investment in water and soil conservation at the mine has reached 170 million yuan ($26 million), he said.

Lei noted that soil and rocks dug out of the pit are used to fill mined areas, thus ensuring that the pit's size remains relatively unchanged.

Similar planting projects will be carried out in the newly filled band as operations continue in the 50-square-kilometer mine.

To promote sustainable use, the company has also changed the way it obtains land use rights.

Instead of buying the rights from farmers-a common practice nationwide-the company rents the land, paying 22,500 yuan per hectare annually.

"When all of the land has been leveled and the soil improved, we will return it to the farmers," Lei said.

"Through consistent efforts, we expect to transform the rough, sandy area into quality farmland that will support large-scale agricultural operations and guarantee handsome incomes for the farmers," he said.

He noted that a forest belt will be planted to anchor the sand and prevent the wind from eroding the soil, and added that all the wastewater generated in the mine is collected for concentrated processing before being reused.