EZ-Up Curtain Stoppings: 

A Practical Solution for Directing Ventilation Airflows 

in Large-opening Metal/Nonmetal Mines 

Objective

 To identify and evaluate a durable, flexible, and practical 

stopping to direct ventilation airflows in large-opening metal/ 

nonmetal mines. 

Background

 Supplying fresh ventilation air to dilute airborne contaminants such as diesel particulate matter, diesel and blasting fumes, 

and silica dust is vital to protect the health of underground mine 

workers. Stoppings and other control devices that are used to 

direct the required airflow to the active working areas are an 

integral part of the mechanical ventilation systems used in 

underground mines. Stoppings should be engineered for the 

pressure dynamics to which they will be subjected at the specific 

location where they will be installed. In addition, they should be 

designed for quick installation and minimal main-tenance, and 

they must maintain their structural integrity when subjected to 

differential air pressures. Due to the size of the entries, 

stoppings in large-opening mines are difficult to con-struct and 

maintain. Flexible curtain stoppings in particular are prone to 

damage from blast pressures and from repetitive flapping due to 

varying air movement in these mines. 

Description

 The EZ-Up curtain stopping (Figure 1) is designed primarily 

for use as a temporary or portable stopping, although test results 

indicate that it may remain durable for an extended time. The 

stopping can be constructed from a variety of fabrics, including 

standard mine brattice. For these particular tests, stoppings composed of two separate curtain materials were evaluated: (1) a 

high-density polyethylene woven fabric and (2) a stringreinforced polyethylene film and polyester fabric. The EZ-Up 

curtain stopping is manufactured with a sewn-in loop so that it 

can be easily laced onto tubing while on the ground and then 

hoisted with a strap and ratchet mechanism system to the mine 

roof. Because the stopping is constructed mainly on the ground, 

miners' exposure to the hazards of working at heights (typically 

20–40 ft) associated with large-opening mines is reduced. The 

EZ-Up curtain stopping is constructed in four phases: (1) preparation and ratchet installation, (2) curtain preparation, (3) curtain hoisting, and (4) securing the perimeter. 

Phase 1 – Preparation and Ratchet Installation

The walls and roof of the stopping installation area should be 

fully scaled to prevent injuries from falling rock during 

construction and to provide a solid foundation to secure the 

stopping. The stopping is attached to the mine roof with four 

brackets anchored by roof bolts. Typically, a 9-in-long by 1-indiam roof bolt anchored in competent roof material will provide 

the proper support to suspend the curtain. A ratchet assembly is 

attached to each bracket. The four brackets are positioned in a 

straight line across the roof of the entry using a string line or laser 

Figure 1.—Schematic of EZ-Up curtain stopping for use in largeopening mines. 

No. 519 May 2006 
device. One bracket should be mounted at each end near the 

wall, with two additional brackets evenly spaced across the 

entry. After mounting, the ratchet mechanisms are ready to 

accept the straps for lifting the curtain. 

Phase 2 – Curtain Preparation

The panels used to make the EZ-Up curtain stopping are 

nominally 12 ft wide; the length is equal to the entry height plus 

an additional 1–2 ft of material to allow the curtain to drape onto 

the mine floor to provide a good seal. The fabric along the top 

edge of each panel is folded over to form a loop through which 

11⁄2- to 2-in-diam tubing or conduit is threaded (Figure 1). The 

individual lengths of tubing can be joined together with either 

threaded or tapered connections. To limit air leakage, each 

curtain panel is overlapped approximately 2 ft onto the adjoining 

panel. The loop at the top of each panel must be cut away on 

one side to allow for the overlap. 

Phase 3 – Curtain Hoisting

 The lift straps are suspended from the ratchet mechanisms 

and attached to the tubing in preparation for lifting. The flatplate hook ends (sewn into the strap by the manufacturer) are 

attached to the tubing by notching a narrow slot into the tubing 

with a small handheld electric grinder. 

 The flat-plate hook is fitted into the notch and bolted if 

needed to secure it to the tubing. After attaching all lift straps, 

the EZ-Up curtain stopping is lifted using the ratchet mechanism. Lifts should be made approximately 5 ft at a time while 

keeping the curtain tubing as level as practical (Figure 2). The 

curtain is hoisted until the top of the stopping is near the roof of 

the mine entry. The ratchets are then secured with the set screws 

provided to lock the mechanisms in place. 

Phase 4 – Securing the Perimeter

 The final step in the installation process is to secure the EZUp curtain stopping to the walls of the entry. First, 2-in by 4-in 

nominal boards are bolted vertically to the entry walls from floor 

to ceiling in line with the edge of the stopping. Excess curtain 

material on the end of the stopping adjacent to the wall is then 

wrapped onto a second set of vertical boards. Care must be 

taken to avoid stretching or wrapping the curtain material too 

tight, as the stopping should be permitted to yield slightly when 

subjected to variable pressures. The wrapped curtain boards are 

then attached to the wall boards using 1⁄4-in by 4-in lag screws. 

Test Results

 Stoppings in large-opening underground mines must 

withstand air blasts associated with development and production 

Figure 2.—Raising the EZ-Up curtain stopping into position.

blasting. The structural integrity of stoppings can be determined 

by subjecting them to known blast loads that simulate mine 

production blasts. Blast pressure tests using unconfined explosive charges were conducted on stoppings composed of two 

different materials: (1) a high-density polyethylene woven 

fabric and (2) a string- reinforced polyethylene film and polyester fabric. Both were constructed as described above. The 

tests were conducted in the large underground entries at 

NIOSH's Lake Lynn Experimental Mine (LLEM). As a benchmark for evaluating the EZ-Up curtain stopping, in-mine blast 

pressures at operating underground stone mines were previously 

measured at approximately 1 psig. The stoppings were subjected to a maximum of 3 psig of blast pressure during the 

LLEM evaluations, with the integrity of the EZ-Up curtain 

stoppings remaining intact. 

For More Information

 For more information on EZ-Up curtain stoppings, contact 

Roy H. Grau III, NIOSH Pittsburgh Research Laboratory, 

Cochrans Mill Rd., P.O. Box 18070, Pittsburgh, PA 15236–

0070; phone: (412) 386–6562; fax: (412) 386–6891; e-mail: 

RGrau@cdc.gov. 

To receive other information about occupational safety and 

health topics, call 1–800–35–NIOSH (1–800–356–4674), or 

visit the NIOSH Website at www.cdc.gov/niosh 

Mention of any company name or product does not constitute 

endorsement by the National Institute for Occupational 

Safety and Health. 

DHHS (NIOSH) Publication No. 2006–137