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13 Tolerance and Acceptability
Here modern risk assessment methods help immensely to see through the apparent
complicated series of scenarios and tolerances and then make a balanced decision
based on a meaningful public engagement process. From a corporate perspective,
the financial consequences of a tailings dam failure or the possible malfunctioning of
thickened, filtered or paste alternatives all carry significant financial consequences.
The problem is that the possible alternatives to slurry deposition have not yet created the same body of knowledge that could support development of professional
guidances and protocols of a quality equal to that for slurry deposition. Thus it is
paramount that the risk assessment used to compare the alternatives can explicitly
tackle the different levels of uncertainties and lead to a result that should be approximately right, rather than precisely wrong.
If a project or an alternative has too many intolerable risks (i.e., the aggregated
intolerable risk is too high), it may be time to drop the project/alternative rather than
build it nevertheless and try to mitigate.
From a public perspective, what defines acceptable risk is not found in the results
of a dam safety review report. As an example, the guideline Legislated Dam Safety
Reviews (APEGBC 2014) states:
The determination of what is the acceptable level of risk or safety for the various elements
which are identified as being at risk is not the role of the qualified professional engineer and is
outside the scope of the dam safety analysis. The acceptable level of risk must be established
and adopted by the regulatory authority in consultation with the dam owner. However, an
assessment of the various elements at risk, through the dam failure consequences classification established by the relevant regulatory authority will guide the qualified professional
engineer’s dam safety analysis.
What this basically states is that a government’s or regulatory authority’s approval
of a design, based on an acceptance of its identified risks, defines what constitutes an
acceptable level of risk. The assurance statement required as part of the Dam Safety
Review Report verifying that “the dam is reasonably safe” means nothing more than
the dam’s level of risk is no worse than that level of risk previously approved by the
government. Clearly the government is the final arbiter as to the determination of
acceptable risk on a case by case situation. The question is: what is the responsibility
of the government in this case?
Voluntary risk can be defined as the risk proceeding from the will or from one’s own
choice or consent. Involuntary risks are generated by situations contrary to or without
choice. In our litigation-prone societies, the distinction becomes fuzzier every day and
is linked to the knowledge of the existence of the hazard. A perfectly ignorant person
can only have involuntary risks, as this person cannot formulate any choice based on
potential hazard exposure. At the other end of the spectrum a perfectly knowledgeable
person only has voluntary risks. Having voluntary risks and not mitigating them can
be considered criminal negligence, thus leading to the paradox of good companies
and individuals hiding the fact they perform good risk assessments, in order to avoid
exposure to legal proceedings.
13 Tolerance and Acceptability
Here modern risk assessment methods help immensely to see through the apparent
complicated series of scenarios and tolerances and then make a balanced decision
based on a meaningful public engagement process. From a corporate perspective,
the financial consequences of a tailings dam failure or the possible malfunctioning of
thickened, filtered or paste alternatives all carry significant financial consequences.
The problem is that the possible alternatives to slurry deposition have not yet created the same body of knowledge that could support development of professional
guidances and protocols of a quality equal to that for slurry deposition. Thus it is
paramount that the risk assessment used to compare the alternatives can explicitly
tackle the different levels of uncertainties and lead to a result that should be approximately right, rather than precisely wrong.
If a project or an alternative has too many intolerable risks (i.e., the aggregated
intolerable risk is too high), it may be time to drop the project/alternative rather than
build it nevertheless and try to mitigate.
From a public perspective, what defines acceptable risk is not found in the results
of a dam safety review report. As an example, the guideline Legislated Dam Safety
Reviews (APEGBC 2014) states:
The determination of what is the acceptable level of risk or safety for the various elements
which are identified as being at risk is not the role of the qualified professional engineer and is
outside the scope of the dam safety analysis. The acceptable level of risk must be established
and adopted by the regulatory authority in consultation with the dam owner. However, an
assessment of the various elements at risk, through the dam failure consequences classification established by the relevant regulatory authority will guide the qualified professional
engineer’s dam safety analysis.
What this basically states is that a government’s or regulatory authority’s approval
of a design, based on an acceptance of its identified risks, defines what constitutes an
acceptable level of risk. The assurance statement required as part of the Dam Safety
Review Report verifying that “the dam is reasonably safe” means nothing more than
the dam’s level of risk is no worse than that level of risk previously approved by the
government. Clearly the government is the final arbiter as to the determination of
acceptable risk on a case by case situation. The question is: what is the responsibility
of the government in this case?
Voluntary risk can be defined as the risk proceeding from the will or from one’s own
choice or consent. Involuntary risks are generated by situations contrary to or without
choice. In our litigation-prone societies, the distinction becomes fuzzier every day and
is linked to the knowledge of the existence of the hazard. A perfectly ignorant person
can only have involuntary risks, as this person cannot formulate any choice based on
potential hazard exposure. At the other end of the spectrum a perfectly knowledgeable
person only has voluntary risks. Having voluntary risks and not mitigating them can
be considered criminal negligence, thus leading to the paradox of good companies
and individuals hiding the fact they perform good risk assessments, in order to avoid
exposure to legal proceedings.