Example MSHA Manual Pages

Some additional typical pages from second edition of the MSHA Engineering and Design Manual are presented below.

Chapter 8, Page 8-21

This page shows an illustration of typical conditions that might be encountered near a coal seam outcrop where weathered joints may represent seepage pathways from a future impoundment. The presence of stress relief fractures or subsidence fractures would exacerbate the concern for seepage and internal erosion.

Chapter 8, Page 8-32

Figure 8.9 illustrates a sliding wedge analysis at an outcrop barrier and the associated free body diagram for computation of forces using the approach proposed by Newman (2003). In applying the analysis, the weight of overburden rock and coal may be taken as the total weight only if the mine workings are not and will not be flooded.

Chapter 9, Page 9-13

At coal refuse disposal sites, decants are generally not intended to discharge at high flow rates, but are designed to remove clarified process water, pass base stream flows or to drain the impoundment of stored water after a storm. Several types of decant systems are shown in Figure 9.5.


Chapter 9, Page 9-100

Schematic examples of decant inlets that are most adaptable to coal refuse disposal facilities are illustrated in Figure 9.38, The primary advantage of the inlet types shown is their access for expansion as the level of settled fine refuse increases. The primary disadvantage is that the length of conduit required upstream of the embankment, beneath the settled slurry, is relatively great.

Chapter 13, Page 13-40

Figure 13.15 provides formulas and a series of curves for estimating flow through a V-notch weir under free-fall conditions (design conditions), as well as an approximate method for estimating flow with downstream submergence of up to 90 percent of the depth of flow through the weir.

Chapter 13, Page 13-43

Figure 13.16 illustrates the application of an automated data acquisition system at a coal refuse disposal impoundment for monitoring piezometer levels and transmitting the data to a mine office more than a mile away.