profit function for mining sand 开采每吨沙土所获利润函数
sand mining on river channel 河道采砂
sand mining plan 采砂规划
sand-mining 长江采砂
sand mining depth 采砂深度
Punish the illegal sand mining 找准根源严打非法采砂
instream sand mining 河道采砂
Oil sand mining began in Alberta in 1967.That first mine is closest to the Athabasca River in the top image (1984).
阿伯达省的油砂矿开始于1967年，最早的矿井是上图（1984年）中离阿萨巴斯卡河最近的那个。
Sand mining further erodes the coast, and ground water drainage to sustain human populations triggers land subsidence even as the sea level rises by around 5mm a year.
采砂业也在进一步侵蚀着河岸，而人类的地下水开采导致地面沉降，与此同时，海平面正以每年5毫米的速度上升。
As natural sandstone resources shortage, countries gradually has formulated a series of policies and regulations to limit natural sand mining.
随着天然砂石资源的逐渐短缺，国家制定了一系列政策法规来限制天然砂石的开采。
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