Examples of the application of microgravity mehtod for the detection of potentially hazardous (empty) underground cavities caused by the collapse of coal mines are presented. Within these areas some alteration by previous remediation activity had occurred. This was not documented earlier and, therefore, such alteration was often unknown prior to the current investigations. We show a successful application of microgravity, leading to the detection of an empty cavity, in close proximity to where concrete injection was earlier performed. This was subsequently verified thorugh measurements in a borehole. In contrast, two other examples delivered results where the microgravity data, along with signals from other geophysical methods, led to the interpretation that subsidence resulting in the formation of sinkholes had been in‐filled, and in these situations the detection of more recent cavities was considered to be unreliable. These results point to the conclusion that microgravity interpretation of cavities is an effective approach, but the success of this approach may be compromised at sites where remediation activity has already occurred; in such situations the approach should be supplemented by other geophysical methods.

中文翻译：

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在坍塌的煤矿上绘制危险腔体的图：使用微重力法的案例研究经验

介绍了微重力方法在检测由煤矿倒塌引起的潜在危险（空）地下洞中的应用实例。在这些区域内，以前的修复活动已经发生了一些变化。较早之前没有记录，因此，在进行当前调查之前，这种改变通常是未知的。我们显示了微重力的成功应用，可导致在较早进行混凝土注入的位置附近检测到空洞。随后，这在井眼中通过测量得到了验证。相比之下，另外两个例子提供的结果是，微重力数据以及其他地球物理方法的信号导致了这样的解释，即导致下沉坑形成的沉陷已被填充，在这种情况下，发现较新的蛀牙被认为是不可靠的。这些结果表明，利用微重力解释型腔是一种有效的方法，但是这种方法的成功可能会在已经发生修复活动的现场受到损害；在这种情况下，应采用其他地球物理方法作为补充。