The Subtropolis Mine is a room-and-pillar mine extracting the Vanport limestone near Petersburg, Ohio, at a depth of approximately 59.4 m (190 ft). In February of 2018, mine management began implementing a new layout to better control the negative effects of excessive levels of horizontal stress. Almost immediately, the conditions in the headings improved. Conversely, and as expected, stress-related damage concentrated within crosscuts. Over the last 18 months, the mine operator has diligently experimented with different techniques/methods to lessen the impact of the instabilities in the outby crosscuts. The range of controls used by the mine operator include angled crosscuts, crosscut offsets, increase distance between crosscuts, arched crosscuts, cable bolted crosscuts, altered blasting pattern, and windows. A window is used to resist roof deformation by leaving a strong brow of roof rock within the crosscuts. A window reduces the crosscut dimensions vertically and, in some applications, horizontally. With each application of engineering controls, conditions were monitored and analyzed using observational and measurement techniques. In every case, the advantages in ground conditions were weighed against its impacts to haulage, ventilation, and other mining considerations. This paper examines how each engineering control was implemented and assessed. All these controls are based on well-established geomechanics principles, but experience has shown that local modifications are needed to deal with the unique local conditions such as geology, mining method, mine equipment, and in situ stress conditions.

中文翻译：

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控制横切面损伤以应对过高水平应力：俄亥俄州彼得堡 Subtropolis 矿的案例研究

Subtropolis 矿是一个房柱式矿，开采俄亥俄州彼得堡附近的 Vanport 石灰岩，深度约为 59.4 m（190 英尺）。2018 年 2 月，矿山管理层开始实施新布局，以更好地控制水平应力水平过高的负面影响。几乎立即，标题中的条件得到了改善。相反，正如预期的那样，与应力相关的损坏集中在横切面上。在过去的 18 个月中，矿山经营者一直在努力尝试不同的技术/方法，以减轻外边横切面不稳定的影响。矿山运营商使用的控制范围包括倾斜横切、横切偏移、增加横切之间的距离、拱形横切、电缆螺栓横切、改变的爆破模式和窗户。窗户用于通过在横切面内留下坚固的屋顶岩石来抵抗屋顶变形。窗口可垂直缩小横切尺寸，在某些应用程序中可缩小横切尺寸。随着工程控制的每次应用，使用观察和测量技术监测和分析条件。在每种情况下，都会权衡地面条件的优势与其对运输、通风和其他采矿考虑因素的影响。本文研究了如何实施和评估每个工程控制。所有这些控制均基于完善的地质力学原理，但经验表明，需要进行局部修改以应对独特的当地条件，例如地质、采矿方法、矿山设备和原位应力条件。