Incentive
Legal liability certainly provides incentive in decision making. From my own experience, eight miners died in a 2.5-million-ton failure on a highwall that I helped to design years earlier. Forensic investigation found that the failure mechanism was unique and there was no fault on my part. The investigation made the sometimes-vague concept of potential liability very real and provided incentive for my future work.
The greatest incentive though is in knowing that people have been saved. I once had a miner crying and thanking me that his children did not lose their father two days before Christmas after I cleared him and others from a work area minutes before a slope failed into it.
Thus, our discussion on slope design and factor of safety is presented within a legal standards and liability framework because legal compliance drives much of decision making. But we believe that safety truly is the foremost concern for operators and our goal is to help to make your workplace as safe as possible. Our specific concern presented here is our observation and interpretation that MSHA-required safety catch benches are not incorporated into some reclamation plans.
SMARA
All mines in California require a Reclamation Plan that conforms with California’s Surface Mining and Reclamation Act (SMARA). The requirement for cut slopes is that “cut slopes, including final highwalls and quarry faces, shall have a minimum slope stability factor of safety that is suitable for the proposed end use and conform with the surrounding topography and/or approved end use” (SMARA Section 3704(f)).
But keep in mind:
“Even a simple engineering design concept such as the Factor of Safety of a slope, which most mine managers, superintendents and mining engineers would think of as an absolute number that is universally applicable, is in reality only a factor of the experience and expertise of the engineer involved in the design process. It is purely an index. …We only see what we know.” (T. D. Sullivan, 2006)
MSHA
The final wall configuration that meets the SMARA requirements must be mined while adhering to the federal Mine Safety and Health Administration (MSHA) regulations. “MSHA requires that a bench located immediately above the area where miners work or travel be maintained in a condition adequate to retain material that may slide, ravel, or slough onto the bench from the wall, bank, or slope” (MSHA Program Policy Manual). This catch bench design requirement is a “Mandatory Health or Safety Standard”.
MSHA provides little specific guidance for compliance with this standard. Design professionals must apply judgment and they typically look to literature regarding rockfall in mines and roadcuts for developing safety catch bench design criteria.
Potential Criminal Liability for Operators
The United States Department of Justice Criminal Resource Manual provides the following guidance for prosecuting a willful violation of a MSHA Mandatory Health or Safety Standard:
Title 30 U.S.C. § 820(d) provides criminal penalties for any operator who willfully fails to comply with a mandatory health or safety standard, or who knowingly violates or refuses to comply with an order under 30 U.S.C. § 814 or § 817. Section 820(d) applies to "operators" of mines subject to the Mine Safety and Health Act. Mines subject to coverage include coal or other mines, the products of which enter commerce, or the operations or products of which affect commerce. See 30 U.S.C. § 803. Note that the Act now covers all mines not just coal mines. See 30 U.S.C. § 802(h)(i). "Operator" is defined to include any owner, lessee, or other persons who operates, controls, or supervises a coal or other mine or any independent contractor performing services or construction at such mine. 30 U.S.C. § 802(d).
…
The leading case on the intent requirement of this statute approves a jury instruction that a failure to comply with a mandatory health or safety standard is willful, "if done knowingly and purposefully by a mine operator who, having a free will or choice, either intentionally disobeys the standard or recklessly disregards its requirements."
SMARA Must be Applied Within Confines of MSHA
An issue that concerns EnviroMINE is that some approved reclamation plans have cut slope designs that meet the SMARA requirements but do not, in our opinion, meet the MSHA Mandatory Health or Safety Standards for catch bench design. In these instances, it appears necessary that to achieve the reclamation plan design, an “operator” will subject themself to potential civil and criminal liability and their employees to undesirable rockfall hazard.
For some operators, EnviroMINE has presented the safety issues and technical arguments to the lead agency to seek approval to amend their reclamation plans to be consistent with MSHA. In some cases, a recommended proper catch bench design allows for steeper final walls than the prior design, allowing for greater resource extraction. In cases where 45-degree bench faces were required by the reclamation plan, which is operationally difficult at best in hard rock, the operator benefits by steepening the bench faces to as steep as can be safely mined. This is consistent with internationally accepted mining practice and well-supported by the mining literature.
The take-away point is that mining to a SMARA-acceptable factor of safety without a proper MSHA-required catch bench design may not be safe.
The reason for this apparent disconnect is that application of SMARA generally looks to deep-seated mechanisms that may cause an entire slope to fail. The mining literature supports that these large failures rarely cause injury because they give advance warning and they are managed. Conversely, most injuries related to mine cut slopes are from rock fall. Fatalities have occurred where as little as a single 4-inch rock that fell from above is the likely killer. This relatively common injury mechanism typically gives no warning, and is mitigated by MSHA’s catch bench design requirement.
MSHA and SMARA Combined are Consistent with International Standards
It is widely accepted as an international standard that a catch bench design is the first design to be performed. The follow-up factor of safety analysis can require a shallower slope if the acceptance criteria are not met using a bench design, but the slope cannot be steeper than what the bench design allows, regardless of the factor of safety.
The acceptable factor of safety typically varies by the acceptable risk level. The factor of safety for a slope with no critical infrastructure in harm’s-way can be lower than that for a slope that contains a ramp or other critical assets above or below. SMARA is consistent with these international risk-based standards where it requires that the factor of safety be appropriate for the end use.
Do Local Standards Trump International Standards?
Where the reclamation plan design is not consistent with MSHA, Sullivan’s observation that “We only see what we know” certainly rings true. Can the engineer/operator effectively invoke the often used liability limitation that states that the ordinary and reasonable care owed is that which is common on the same type of project, at the same time and in the same place, under similar circumstances and conditions? Or is this a situation where, in considering local custom, “Courts must in the end say what is required; there are precautions so imperative that even their universal disregard will not excuse their omission” (The T.J. Hooper, 60 F.2d 737 (2d Cir. 1932))?
Slope Stability Experience
Since 1994, Dr. Sims has worked on slope design analysis and recommendations for aggregate, limestone, borax, lithium, phosphate, diamond and large metal mines in North and South America and Asia. He has trained geologists and engineers for data collection and slope stability analysis at many world-class mines.
Legal Disclaimer
Because Dr. Sims is a member of the Arizona Bar, and this article discusses legal issues, the following disclaimers are provided:
*No Legal Services are offered and there is no intention to provide Legal Services or Legal Advice in this newsletter or in any communications with Danny Sims.
*No Attorney- Client Relationship can be created in communications with Danny Sims.