ARMPS–HWM: 

New Software for Sizing Pillars for Highwall Mining

 The use of highwall mining systems (Figure 1) has 

increased substantially in open-pit coal mines. It is used 

where overburden depth exceeds economical recovery. 

Highwall stability remains the major safety concern during 

highwall mining. The Mine Safety and Health Administration requires highwall mining operators to follow ground 

control plans that specify the pillar sizes necessary to prevent 

a pillar collapse that would threaten highwall stability. 

 NIOSH has developed the Analysis of Retreat Mining 

Pillar Stability-Highwall Mining (ARMPS–HWM) computer 

program to assist mine planners with pillar design. Based on 

extensive research into instances of highwall mining pillar 

instability and pillar collapses in underground mines, 

ARMPS–HWM uses the Mark-Bieniawski formula to 

estimate the strength of long strip pillars. The suggested 

design procedure addresses the following issues:

• The number of holes between barrier pillars; 

• The size of the individual web pillars; 

• The size of the barrier pillars; and 

• The stability factor of the overall design. 

The program is simple to install and easy to use. It 

contains extensive “Help” files that provide more 

background on the research upon which design formulas 

are based. The Help files also contain suggestions for 

highwall mining through old auger holes and for closeproximity, multiple-split highwall mining. 

 For more information, contact Christopher Mark, 

Ph.D. (412–386–6522; CMark@cdc.gov), or R. Karl Zipf, 

Jr., Ph.D. (412–386–4097; RZipf@cdc.gov), at the NIOSH 

Pittsburgh Research Laboratory. 

Figure 1.—Highwall mining, showing a barrier pillar (left) and a web pillar (right). 

No. 516 March 2006 
 To obtain a free copy of ARMPS–HWM and 

other NIOSH ground control software packages, visit 

the NIOSH Ground Control topic page at: www.cdc.gov/

niosh/mining/topics/groundcontrol/groundcontrol.htm. 

You may also contact Kim Mitchell at 412–386–6552, 

e-mail: KAMitchell@cdc.gov. Or you may complete 

the order form below, detach, and mail to: Kim 

Mitchell, NIOSH Pittsburgh Research Laboratory, 

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

15236–0070, or fax to 412–386–6891. 

DHHS (NIOSH) Publication No. 2006–128

— — — — — — — — — — — — — — — — — — — — — — — — — — — — — — 

G Please send me a free copy of ARMPS–HWM, along with other NIOSH ground control software. 

Name ____________________________________________________________________________________________ 

Title _____________________________________________________________________________________________ 

Organization ______________________________________________________________________________________ 

Address __________________________________________________________________________________________ 

City _________________________________________ State _________________ Zip Code ___________________ 

Country _________________________________________________________________________________________ 

e-mail ____________________________________________________________________________________________ 

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.