T e c h n i c a L P a P e r s

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Water and slurry bulkheads in 


underground coal mines: design,
 

monitoring and safety concerns
 

S.P. HarteiS and d.r. dolinar 

S.P. Harteis and D.R. Dolinar, member SMe, are mining 

engineers with the national institute for occupational Safety 


and Health (nioSH), Pittsburgh, Pa. 

Abstract 

Many mining operations rely on bulkheads to provide 

a barrier between impounded water or slurry and active 

mine workings. However, bulkhead failures can cause 

catastrophic flooding that puts the underground workforce 

at risk.The U.S National Institute for Occupational Safety 

and Health (NIOSH), in collaboration with the U.S. Mine 

Safety and Health Administration, is conducting research 

to evaluate the adequacy of existing design practices for 

retention bulkheads. A key component of this research effort is the documentation of the performance history and 

design parameters for bulkheads installed in underground 

coal mines during the last 20 years or more.This research is 

part of a larger effort to develop general design guidelines 

and procedures for constructing and maintaining bulkheads, with such guidelines designed to help ensure their 

long-term structural integrity while significantly reducing 

the inundation risk for miners. 

This paper presents the results of NIOSH’s research to 

identify state-of-the-art bulkhead designs, including design 

criteria, leakage monitoring systems and emergency warning systems. Underground observations and evaluations of 

existing bulkheads suggest that the most important design 

factors influencing their performance are the interface of 

the bulkhead with the surrounding strata and the potential 

magnitude of the hydraulic pressure to which they may be 

subjected. When a bulkhead has failed, leakage has generally been through the surrounding strata or along the 

bulkhead/strata interface, with the failure potential along 

the interface increasing with hydraulic head. It was also 

determined that development of a monitoring program to 

ensure the long-term structural integrity of bulkheads is an 

important safety consideration. Current monitoring procedures range from weekly visual inspections to constant 

monitoring via pressure transducers and fluid level indicators.Where possible, these devices are used in conjunction 

with a computer-based mine-monitoring system to alert 

mine personnel when an emergency condition exists at the 

bulkhead installation. 

Introduction 

Underground mines install bulkheads across openings for a variety of 

reasons (Table 1). Bulkheads are most 

commonly used as a dam to contain water or liquid-like mine wastes (tailings 

or slurry) in abandoned mine workings 

(Fig. 1). Bulkheads are also used as regulators to restrict the flow of water from 

abandoned mine workings into active 

mining operations. In some cases, where 

abandoned mine workings are located beneath a refuse 

impoundment, bulkheads are installed at the surface entrances to the abandoned mine workings to prevent the 

outflow of water and liquid-like mine wastes from the 

openings if the overlying refuse impoundment should 

break through into the abandoned mine workings. Failure of any of these bulkheads could result in a disastrous 

inundation, with the potential for significant loss of life or 

property and possible damage to the environment. 

While no mining fatalities have been directly attributable to bulkhead failure, recent catastrophic mine inundations have underscored the need for sound engineering 

practices in the design and maintenance of these structures to decrease the potential for loss of life. On March 

1, 1991, bulkheads designed and constructed to impound 

water were installed across the main entries between the 

abandoned Raccoon No. 3 Mine and 

the down-dip and active Meigs No. 31 

Mine. On July 11, 1993, an inundation 

occurred at Meigs No. 31 Mine when 

these bulkheads failed. Fortunately,
 

early discovery of the failure and a 

sufficiently slow water flow enabled 

all miners to escape from the Meigs 

No. 31 Mine. A subsequent investigation by the U.S. Mine Safety and 

Health Administration (MSHA) 

(Tulanowski et al., 1993) indicated 

that the likely failure mechanism was erosion (or piping) 

along the concrete/fireclay interface at the base of the 

bulkhead. 

1

Disclaimer: The findings and conclusions in this 

report are those of the authors and do not necessarily 

represent the views of the National Institute for Occupational Safety and Health. 

In 2002, the U.S. Congress requested that the National 

Research Council investigate the Oct. 11, 2000, failure of 

the Martin County Coal impoundment near Inez, KY. In 

this incident, more than 950 million L (250 million gal) 

of impounded slurry broke through a bulkhead, flowed 

through an underground mine and ultimately discharged 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

into nearby creeks and streams, causing significant environmental damage. Fortunately, the incident caused no 

injuries or fatalities. Wu et al. (2003) noted that several 

other breakthroughs of slurry into underground mine 

workings similar to this incident have occurred in recent 

years. 

Figure 1 	

A masonry block bulkhead installation with a pass-through pipe and a pressure-monitoring device (Checkan, 1985). 

Prior to construction of any bulkhead, MSHA and, 

possibly, state agencies, must review and approve the 

design. This usually entails submission of a proposed design by a registered professional engineer for evaluation by the MSHA Technical Support Group. However, 

comprehensive engineering guidelines for the construction of reliable underground bulkheads do not currently 

exist. This makes it difficult for mine operators to design bulkhead installations. State and 

federal agencies have also expressed 

a need for design guidelines to assist 

in their permit review and approval 

process. The information contained 

in this report is part of a larger effort 

to develop general design guidelines 

and procedures for constructing and 

maintaining bulkheads that will help 

to ensure their long-term structural integrity while significantly reducing the 

inundation risk for miners. 

Existing and proposed 

`bulkhead installations 

To understand the requirements 

for bulkhead installations and the permitting process, researchers from the 

U.S. National Institute for Occupational Safety and Health (NIOSH) examined the bulkhead permits submitted 

to the MSHA Technical Support office 

in Bruceton, PA. Researchers then visited MSHA district offices and state 

mining agencies and contacted engineering consulting firms to document 

submitted permitting information and 

determine the number of installed 

bulkheads and their locations in U.S. coal fields. Once 

this information was tabulated, accessible bulkheads at 

underground mining operations were visited (Fig. 2) to 

gather information on monitoring methods and procedures, emergency response plans, construction practices 

and maintenance issues. A total of 34 bulkhead sites (existing or in the permit stage) were identified in the 11 

MSHA districts (Table 1). 

Table 1 

Functional types of bulkheads installed in underground coal mines. 

MSHA Number of Water Surface refuse Slurry Mine Permitted Permit 

district bulkhead sites storage disposal injection fire but not built review 

related 

1	 0	 -	 -	 -	 -	 -	 ­

2	 7	 5	 -	 -	 2	 -	 ­

3	 4	 3	 -	 -	 1	 -	 ­

4	 8	 3	 3	 -	 -	 -	


2
 

5	 3	 1	 -	 -	 -	 2	 ­

6	 3	 -	 3	 -	 -	 -	 ­

7	 0	 -	 -	 -	 -	 -	 ­

8	 1	 -	 -	 -	 -	 1	 ­

9	 1	 1	 -	 -	 -	 -	 ­

10	 4	 2	 -	 2	 -	 -	 ­

11	 3	 2	 -	 1	 -	 -	 ­

Total 34 17 6 3 3 3 2 

Of the 34 bulkhead permit applications reviewed, 

17 were constructed to create an active water reservoir 

or control water flow from abandoned mines (Table 1). 

These installations rely on pumps to maintain the impounded water at a safe level or drain pipes that regulate the flow of water out of an abandoned area. At one 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

operation, the mine manager stated that the active mine 

has been idled during times of high water flow, but the 

bulkheads sufficiently regulated the flow to prevent inundation of the active works. 

Figure 2 

Researcher examining a bulkhead installation in an 

underground coal mine. 

Six bulkhead installation sites were used for refuse 

disposal. Two were installed across abandoned mine 

openings in the footprint of a surface impoundment to 

allow disposal of mine refuse to an elevation above the 

mine workings and prevent water or slurry from entering 

inactive mine works (U.S. Department of Labor, 2003). 

The remaining four bulkheads were constructed as a secondary line of defense in the event of an unexpected 

inrush of water or slurry into the mines from impoundments located on the surface above the abandoned mine 

works. 

Of the remaining 11 installations, three bulkheads 

were constructed to seal off an underground area for 

slurry injection. Three were built to contain water to inundate an area of the mine in an attempt to extinguish a 

mine fire. Permits were issued for bulkheads at three sites, 

but as of this writing they have not been constructed.The 

remaining two sites are in the permitting stage. 

Permitting process 

Guidelines do not currently exist for preparing an 

MSHA or state permit application for a bulkhead installation. As a result, bulkhead permit applications that do 

not contain sufficient information are frequently submitted to federal and state agencies for approval. When the 

application is received in the MSHA district office, it is 

forwarded to the Technical Support Group located in 

Pittsburgh, PA, for its review and comments. The Technical Support Group reviews the submitted information 

and develops a list of comments and recommendations 

for additional items to be addressed. The MSHA district 

office then forwards the list of comments and recommendations to the permit applicant. Once the applicant 

receives MSHA’s comments, they submit a response to 

the MSHA district office.The response is reviewed by the 

MSHA district office and may be returned to the Technical Support Group for any additional review and comment.This procedure is repeated until MSHA is satisfied 

that all aspects of the bulkhead installation are adequately addressed. At some locations, state agencies follow a 

similar permit approval process. It is recommended that 

the permit applicant contact the appropriate state agency 

to explore specific permitting requirements. 

In an attempt to improve the engineering content 

and expedite the permitting process, NIOSH developed 

the following summary of information that is generally 

required by MSHA for permitting a bulkhead installation. It is not intended to be an all encompassing list, but 

information to assist the permit applicant in designing a 

safe and efficient bulkhead system. 

Basic permit requirements. A bulkhead installation 

permit may be treated as a part of the mine ventilation 

plan, refuse disposal plan, abandonment plan or an independent plan. Before the actual bulkhead permit is developed, a joint meeting should be held with representatives 

of MSHA and the appropriate state agency to discuss the 

bulkhead installation and permitting requirements. This 

will give the applicant a chance to explain the need for 

bulkheads and the anticipated operating parameters.The 

permit review procedure should be discussed to determine what information is required and to establish points 

of contact for each party involved in the permitting and 

construction of the bulkhead. Maintaining open lines of 

communication can play a key role in timely approval. 

In addition to the information discussed in the following 

sections, the following general items will be required in 

the permit package: 

•	 a mine map showing the proposed locations of the 

bulkheads and showing the mine floor elevation 

contour lines with an indication of the extent of the 

expected water pool; 

•	 a mine map showing the expected water flow path 

or paths if a bulkhead should fail and showing areas 

where water may discharge and perhaps accumulate, 

on the surface, if applicable; 

•	 a written discussion of why bulkheads are needed and 

how the lack of these structures will adversely impact 

the mining operation; 

•	 a written procedures to maintain the proposed water or 

slurry elevation of the underground impoundment; 

•	 a chemical analysis of the water or slurry to be impounded; 

•	 a map of any adjacent, overlying and underlying mine 

workings (active and inactive); 

•	 a map of surface features such as ponds, lakes, streams, 

rivers, impoundments and any other sources of water 

that could impact the integrity of the bulkhead; and 

•	 a discussion of potential consequences if bulkhead 

system fails and a plan of action to mitigate such consequences. 

Geotechnical considerations. The mine layout will 

determine the location for the bulkhead. Therefore, geotechnical information on the site-specific conditions is 

required, especially considering that most known bulkhead failures have been through the surrounding strata 

or along the strata/bulkhead interface. Geotechnical factors that should be addressed include the geology, hydrology and ground-control issues. 

The geologic characteristics and conditions for the site 

where the bulkhead will be constructed need to be identi­
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

fied and evaluated.The strata in the immediate roof, floor 

and ribs should be described in detail and should include 

all strata that could be affected by a change in hydrologic 

conditions or the bulkhead installation. In many cases, the 

immediate floor or roof consists of an underclay, fireclay 

or other weak material that may degrade when exposed 

to water. So a site evaluation must be done to a depth 

where competent strata is identified that will not be affected by water. Data on the strata strength and effects of 

water exposure should be included to indicate the strata 

competency. Any conditions associated with the mined 

coal bed, such as clay or rock partings or cleat properties, 

that could be adversely affected by exposure to water 

and thus become a conduit for water flow around the 

bulkhead must be identified. 

MSHA 

district 

1	 

Number of 

bulkhead sites 

0	 

Parallel 

plug 

-	

Tapered 

plug 

-	

Notched 

slab 

-	

Grouted 

rock 

-	

Cap 

-

2	 7	 1	 -	 6	 -	 -

3	 4	 3	 -	 1	 -	 -

4	 6	 -	 2	 2	 1	 1 

5	 3	 -	 -	 3	 -	 -

6	 3	 1	 -	 1	 -	 1 

7	 0	 -	 -	 -	 -	 -

8	 1	 -	 -	 1	 -	 -

9	 1	 -	 1	 -	 -	 -	

10	 4	 1	 -	 3	 -	 -	

11	 3	 2	 -	 1	 -	 -

Total 32 8 3 18 1 2 

Table 2 

Types of bulkhead designs used in underground coal mines. 

From a ground-control standpoint, there are general 

area and site-specific stability issues that should be addressed. The stability of the pillars in the general area 

of the bulkhead installation should be evaluated. Coal 

pillars, to which bulkheads will be anchored as well as 

adjacent pillars, must remain stable for the life of the impoundment. Engineering calculations that demonstrate 

a sufficient safety factor for long-term stability of these 

pillars should be included. If future mining adjacent to 

the underground impoundment is planned, documentation showing the effects of this proposed mining on the 

stability of the impoundment should be submitted. This 

should include information on the stability of the barrier 

pillar and development pillars. 

The stability of the site-specific openings where the 

bulkhead is to be placed should also be addressed. The 

bulkhead should be constructed where competent roof 

and floor strata exist. Every effort should be made to 

avoid placing a bulkhead near pillar corners where the 

rib, roof and floor strata commonly exhibit increased 

fracturing. Any potentially adverse ground control conditions should be evaluated. These include roof falls, pillar punching, floor heave, pillar bursts or other unusual 

conditions in the entry area where the bulkheads are to 

be installed. The permit package should include details 

of existing roof-support practices and planned additional roof support to protect the bulkhead structure, inby 

and outby. Soft floor material should be removed before 

installing posts or cribbing for roof support. Supports 

inby the bulkhead will be exposed to water or slurry and 

should be designed accordingly. Because long-term monitoring of the bulkheads will be required, additional roof 

and rib support should be considered along the travel 

ways that will be used for inspection purposes. 

When it has been determined that the strata surrounding the bulkhead has the potential for leakage 

with long-term exposure to water, the steps necessary to 

mitigate this condition should be addressed in the permit 

package. If the mine floor or roof is prone to erosion or 

degrades significantly when exposed to water, it must be 

removed from the footprint of the bulkhead so that it can 

be constructed on hard, competent rock. In some operations, there is a potential for coal pillars located inside the 

impoundment area to push through the saturated floor 

strata. If this condition exists, its effect on the stability 

and safety of the impoundment, along with any proposed 

engineering solutions, should be addressed. 

Because the strata surrounding the bulkhead may 

contain fractures that could allow water to leak around 

the bulkhead, the need for sealing the strata and associated fractures should also be evaluated.This sealing process could include the drilling of holes into the strata and 

pumping grout into the fractures. Further, consideration 

should be given to sealing any water-sensitive strata that 

cannot be removed for a sufficient distance around the 

bulkhead to minimize leakage and prevent large volumes 

of water from flowing into the underground workplace. 

Essentially, measures may need to be taken to increase 

the length of any potential water flow paths through the 

strata and around the bulkhead. To what degree the surrounding strata and fractures may have to be sealed will 

depend on the expected water head behind the bulkheads and the bulkhead design. Due to the strata conditions and the potential for excessive leakage through the 

strata, grout injection into the surrounding strata was 

either performed or planned for nearly two-thirds of the 

bulkheads that were installed or permitted. 

If the impoundment area is adjacent to mine workings, documentation should be provided to demonstrate 

that the barrier separating the impoundment from the 

adjacent works will remain stable and will not rupture. 

This would prevent water or slurry from breaking into 

the adjacent works or seeping through the coalbed and 

surrounding strata. Similar documentation should be submitted if the impoundment is adjacent to the coalbed 
outcrop.	 

Bulkhead structure. Table 2 gives a breakdown of the 

bulkhead designs currently in use at U.S. mine sites. The 

primary designs for underground use are tapered plugs, 

parallel plugs, notched slabs or variations of these basic 

designs (Fig. 3). Bulkheads installed at mine entrances 

on the surface to prevent water from entering a mine 

may use a reinforced concrete structure built in front 

of the mine opening to “cap” off the opening (Fig. 4) or 

pneumatically stowed crushed limestone in the entry 

between two concrete block walls with injected grout or 

polyurethane into the crushed limestone to form a water 

tight seal (Fig. 5). 

Figure 3 

Three basic designs used for bulkheads constructed 

in underground coal mines (Garrett and Campbell Pitt, 

1958). 

The design that best suits the site-specific application 

depends on several variables. These include the anticipated water or slurry load (head pressure); accessibility 

to the site from underground as well as from the surface; 

rib, roof and floor conditions; floor heave; convergence; 

materials-handing restraints and cost. 

A range of construction materials have been used 

in bulkheads (Table 3). The selection of a construction 

material depends on the bulkhead design selected, the 

accessibility to the installation site and cost. 

The bulkhead structure must be designed to withstand 

the expected maximum head pressure with an appropriate margin of safety. To determine the maximum head 

pressure, the engineer must consider the water or slurry 

to be stored in the impoundment behind the bulkhead. 

He or she must also consider potential additional sources 

of water, such as ground water in overlying or underlying 

adjacent mines. One of the operations visited by NIOSH 

researchers had experienced an increase in water discharge when pumps were removed from service and the 

water level in an abandoned underlying coal mine rose 

above the elevation of the active mine. 

Sources of surface water such as slurry impoundments, rivers or streams that could find their way into 

the underground impoundment must also be considered 

when calculating the potential head pressure acting on a 

proposed bulkhead. Once the maximum design pressure 

is established, the normal operating pressure should be 

calculated based on the usual inflow rate and the rate 

at which water will be removed from the impoundment 

area. Some operations rely on surface or deep well pumps 

to remove water and maintain a normal operating pressure on the bulkheads, while others use pumping stations located underground. One installation evaluated 

by NIOSH was designed to allow mine water to build up 

against the bulkhead until it discharged from an existing 

portal by natural flow, thus limiting the normal operating 

pressure. Regardless of the method used, details must be 

provided in the permit application addressing how the 

normal water or slurry level will be maintained. 

Structural calculations are required in the permit applications to show that the proposed bulkhead design 

will withstand the maximum expected head pressure. 

This section of the permit application must include the 

types of construction materials to be used, the strength 

values of the surrounding strata (including the source of 

this information) and the bulkhead construction material 

properties and characteristics (including those of any reinforcement steel).The calculations should be performed 

under the supervision of a registered professional engineer who has experience in the design and installation of 

water-retention structures and who is also familiar with 

underground mining. The specific calculations required 

will depend on the type of bulkhead structure.These calculations will not be covered in this report. However, adequate safety factors must be used in all bulkhead designs 

due to unknown conditions that could exist in the mine 

roof and floor, the quality of construction and the mine 

safety consequences associated with a potential failure. 

Other design parameters to consider include: 

•	 Steel reinforcement placed inside the bulkhead structure should be coated to prevent corrosion. 

•	 Cement-based products proposed to construct bulkheads in large pours will require a detailed plan to 

reduce the heat of hydration to avoid expansion/contraction as a consequence of heating. 

•	 Selected construction materials must be compatible 

with the quality of water or slurry stored. Specifically, 

they must resist deterioration by acid mine water. 

•	 It is normal for bulkheads to contain pipes that pass 

through the structure to monitor pressures on the 

bulkhead and to release water in emergency situations 

(Kirkwood andWu,1995).Pipes installed to reduce the 

water level should contain a U-trap on the downstream 

end and a means to prevent clogging of the pipe on the 

upstream end. The pressure-monitoring pipe should 

include a visual pressure gauge and shutoff valve.This 

pipe should also be protected from clogging. These 

pipes should be equipped with anti-seep or external 

collars to reduce leakage along the interface of the pipe 

and bulkhead structure.All pipesshould be coated for 

corrosion protection. 

•	 If the bulkhead is located in a seismically active area, 

the design should consider what effect the dynamic and 

hydrodynamic forces that result from an earthquake 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

will have on the bulkhead structure. 

Table 3 

Types of materials used to construct bulkheads. 

MSHA 

district 

1	 

Concrete 

–	

Cementitious 

foam 

–	 

Polyurethane 

limestone 

–	 

Polyurethane 

–	 

Masonry 

–	

Shotcrete 

– 

2	 4	 –	 1	 1	 1	 – 

3	 2	 –	 1	 1	 –	 – 

4	 2	 2	 1	 –	 –	 1 

5	 1	 –	 2	 –	 –	 – 

6	 2	 –	 1	 –	 –	 – 

7	 –	 –	 –	 –	 –	 – 

8	 –	 –	 1	 –	 –	 – 

9	 1	 –	 –	 –	 –	 – 

10	 1	 –	 3	 –	 –	 – 

11	 2	 1	 –	 –	 –	 – 

Total 15 3 10 2 1 1 

Detailed bulkhead construction procedures should 

be listed in the permit application. Information should 

include site preparation requirements; procedures for 

roof, floor and rib hitching; the thickness of material lifts 

if applicable and procedures to seal the interface between the bulkhead and the surrounding strata. Quality-control procedures should also be included to address 

how and what construction materials would be sampled 

for testing. This includes sampling rate, sampling procedure, required laboratory testing, required results and 

measures to be taken if test results indicate substandard 

material. 

Monitoring. The permit application should include 

provisions for a competent person to monitor the construction of the bulkhead. The duties of this person 

should include, but are not limited to, maintaining a 

daily log with photos of construction activities, monitoring construction progress to assure compliance with the 

approved plan, ensuring the sampling of construction 

materials and documenting any variances from the approved plan. 

Once the bulkhead is constructed, it will require routine monitoring of key performance parameters. At a 

minimum, the date, time, pressures, leakage rates and 

visual observations should be recorded and maintained 

in the mine office. The frequency of the inspections will 

depend on the location of the bulkhead, the head pressure, the location of active works with respect to the impoundment and other operating conditions. Normally, 

these inspections become part of the regularly required 

airway examinations. The permit application should include a list of the information to be recorded during the 

inspection and the proposed inspection frequency. 

The head pressure against the bulkhead should be 

monitored using a pressure gauge with a visual indicator connected to a pipe passing through the bulkhead 

structure. The permit application should include details 

of how the pipe will be installed and what measures will 

be taken to prevent the pipe from plugging. When possible, mine operators should connect bulkhead pressure 

transducers to their existing mine monitoring system. 

This allows for constant monitoring and provides a record of the bulkhead pressure changes over time. An 

added benefit is the ability to preset threshold pressure 

levels that, when exceeded, will cause the system to send 

an alarm to the mine office. If a mine-wide monitoring 

system is not in place, commercial stand-alone datagathering systems are available for monitoring bulkhead 

pressures. Regardless of the system chosen, the permit 

will need to state what system is to be used, where the 

information will be monitored and how the information 

will be stored and maintained for future reference. Consideration should also be given to including a backup 

system independent of the primary system to monitor 

water pressures against a bulkhead. One option is to use a 

surface borehole equipped with a piezometer to measure 

the water depth in the mine impoundment. Once the pool 

elevation is determined, one can calculate the resultant 

pressure on the bulkhead. 

Minor leakage through the strata adjacent to the 

bulkhead systems is not abnormal, especially if the hydrostatic head is high. Plans to monitor the bulkhead system 

leakage rate should be included. Once the bulkhead is 

in place, this information will be valuable in determining what areas need additional grouting and can also be 

a measure of bulkhead or adjacent strata degradation 

over time. Some operators construct a low threshold dam 

in front of (outby) the bulkhead to capture the leakage 

and pass it through a V-notch weir. The height of water 

above the apex of the V-notch can be used to calculate 

the leakage rate. Other operators construct a similar dam 

to capture the leakage and gravity feed it into a pipe that 

discharges into an existing sump. The leakage rate can 

be determined by filling a graduated cylinder directly 

from the pipe and recording the time required to fill the 

cylinder.The leakage rate is recorded during each routine 

examination along with the bulkhead pressure. The data 

are recorded on a chart in the mine office.The data show 

the leakage rate and the bulkhead pressure versus time. 

Emergency planning and training. An emergency response and evacuation plan should be developed and included in the permit application package.The plan should 

include a list of events that would trigger an emergency 

response, what actions are to be taken and who is responsible for coordinating these actions. The triggering event 

could be a sudden increase in pressure at the bulkhead, 

a deterioration of the bulkhead structure or surrounding 

strata, an increased leakage or any other indication that 
 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

the bulkhead system could be in jeopardy. Actions could 

include more frequent bulkhead inspections, reducing 

the water or slurry elevation in the impoundment to an 

acceptable level given the developing conditions/problem, the removal of employees from areas that could be 

inundated if a bulkhead failed or a complete evacuation 

of the mine. 

Figure 4 

Reinforced concrete “cap” bulkhead installed across 

drift opening to contain an unexpected inrush of water or 

slurry from surface impoundment above the abandoned 

mine works. 

Figure 5 

Grouted rock bulkhead installed across drift opening. 

The emergency plan should include maps with the 

potential inundation area delineated, emergency exit 

routes, emergency supply locations, access to communication and designated meeting locations. If part of the 

emergency plan is to drain water through the bulkheads, 

a map should be included indicating the water flow path 

and location of areas that will pool water.When establishing exit routes, close attention must be paid to mine floor 

elevations. Existing primary and secondary escapeways 

may become impassable during a bulkhead failure and 

air courses could flood and change ventilation patterns. 

Training is the cornerstone of an effective emergency 

plan and should be included in the permit package. All 

employees exposed to a bulkhead system should be familiar with the installation and receive training on procedures to follow if an inundation or failure occurs. At a 

minimum, annual retraining should be conducted with 

each employee and all workers should be made aware 

when changes occur in the emergency escape routes or 

procedures. 

Summary 

Designing and permitting an underground bulkhead 

system is not a simple task. Engineering design considerations for the bulkhead structure must include its interaction with the surrounding strata, how it will impact 

the underground operations and, most importantly, the 

potential risk to the underground workforce.A registered 

professional engineer who has significant experience in 

the design and installation of water-retention structures 

and is familiar with underground mining should design 

the bulkheads. A detailed plan for the bulkhead installation should be developed and the actual installation 

should be closely monitored. 

Acknowledgments 

The authors acknowledge the assistance of Terence 

M.Taylor, senior civil engineer with MSHA’s Mine Waste 

and Geotechnical Engineering Division, for providing 

information on existing and planned bulkhead permits. 

References 

Checkan, G.J., 1985, “Design of bulkheads for controlling water in 

underground mines,” U.S. Bureau of Mines Information Circular 9020. 

Garrett, W.S., and Campbell Pitt, P.L.T., 1958, “Tests on an experimental underground bulkhead for high pressures,” Journal of the South 

African Institute of Mining and Metallurgy, pp. 123-143. 

Kirkwood, D.T., and Wu, K.K., 1995, “Technical considerations for 

the design and construction of mine seals to withstand hydraulic heads 

in underground mines,” Preprint No. 95-100, presented at the 1995 SME 

Annual Meeting, 1995, Denver, CO. 

Tulanowski, R.T., Kirkwood, D.T., and Gardner, G.H., 1993, “Noninjury water inundation, Meigs No. 31 Mine,” U.S. Department of Labor 

Accident Investigation Report. 

U.S. Department of Labor, 2003, “Report to Congress: responses 

to Recommendations in the National Research Council’s Report Coal 

Waste Impoundments: Risks, Responses and Alternatives,” pp. 37-46. 

Wu, K.K., Owens, H.L., and Fredland, J.W., 2003, “MSHA’s review 

of impoundment plans,” Preprint No. 03-099, presented at the 2003 SME 

Annual Meeting, Cincinnati, OH.