Mining Contract: Calibrating the LaModel Program for Deep Cover Pillar Retreat Coal Mining

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Contract # 200-2008-24752
Start Date 4/18/2008
End Date 9/1/2009
Research Concept

At the time of the tragic Aug. 6, 2007, Crandall Canyon collapse, the mine was performing pillar retreat mining at cover deeper than 1500 feet. Several questions have been raised on the accuracy of the analysis tools currently available and methods that can be used for design purposes to help ensure that these types of tragic events are not repeated. One such method, the LaModel program, is widely used for pillar design, particularly in deep cover, and could be useful in preventing such a tragedy for recurring. A standardized method of calibrating the LaModel program needs to be completed.

Contract Status & Impact

This contract is complete. To receive a copy of the final report, send a request to

On August 6th, 2007, the Crandall Canyon Mine in Utah collapsed trapping six miners. Ten days later during the rescue effort, another collapse occurred killing three rescue workers, including a federal employee.

In an effort to develop improved methods and designs for safer retreat mining practices, the U.S. Congress included specific mention of this need in its final 2008 Budget Appropriations Bill. This contract is one effort to advance these design practices.

The success and accuracy of design methodologies for safe retreat mining analysis is largely dependent on the accuracy of the input parameters. One such design methodology is the LaModel program, which was developed by and is maintained at West Virginia University. However, the program must be properly calibrated against actual case studies in order to allow NIOSH to conduct a detailed comparison between the LaModel program and the Analysis of Retreat Mining Pillar Stability (ARMPS) software, and existing NIOSH ground control software.

As a function of this contract, the university will:

  • Analyze and model 40 deep-cover case histories using the LaModel numerical software.
  • Develop best practices for using LaModel.
  • Implement efficiency and accuracy enhancements to LaModel
  • Develop a risk-based strategy assessment of retreat mining that mine managers can use to make better decisions about whether or not to extract of coal pillars.

Once NIOSH has evaluated, calibrated, and analyzed LaModel against the ARMPS software, the resulting products will be made accessible for public use.

Page last reviewed: September 18, 2020
Page last updated: September 18, 2020