110
8 System Definition
the assumptions on the project environment, chronology etc., also helps defining the
system.
With these definitions it is now possible to dissect the elements of the system
within the considered perimeter.
It is important to note that elements within the system and elements in the environment can be threats-to other elements (for example, a dam breach can damage
another infrastructure) or threats-from (for example, a malevolent act on a pipe by
angry residents).
Threat-to/threat-from is a type of analysis used to link identified external or internal
hazards, for instance:
to particular targets (elements of the system) OR
from elements to targets lying outside of the system (population, environment, third
parties, etc.) or inside the system (which then become interdependent).
As a result each couple is qualified in terms of possible dire outcomes (consequences).
Highly-respected geotechnical professionals maintain that highest “risk” to “safe”
dam operation is the mill, as the mill always underestimates the amount of water
storage capacity they need for a wide variety of reasons. While directly connected,
reportedly the ability to manage contaminant levels and the longer retention times
required was found to be of most concern prior to the introduction of cyanide codes
and guidances (ICMI 2018; Cyanide Code 2017). In order to develop a study compatible with the budgeted effort, assumptions and simplifications will generally be
necessary.
The system can be described by “nodes” as shown in Fig. 8.2 where a tailings
dam is split in three nodes: crown (altitude); impervious core (percolation); and
upstream and downstream bodies (stability). Each node has incoming “resources”,
internal “processes” and outgoing “resources”, and many of the resources flows can
be bi-directional, i.e., affected by inter-dependencies.
Any mining system, no matter how complicated, can be described by as a system
of nodes whose granularity is appropriately selected. Indeed, at the beginning the
nodes may be “macro”, i.e., encompass complex processes; for example, there might
be a macro-node called “mill”. When needed the “mill” node can be subdivided into
increasing finer levels of granularity, going all the way, for example, to a node called
“tailings pump A”. The level of granularity is dictated by the stage of development (at
pre-feasibility level only macro-nodes may be necessary) and the purpose of the risk
assessment (part of the system may be modelled with macro-nodes, others be more
detailed). The advantage of scalability becomes evident as the phases of development
progress.
A well-defined system will avoid many blunders and confusions (https://www.
riskope.com/2017/07/26/three-ways-to-enhancing-your-risk-registers/) typical of
common practice risk registers.
8 System Definition
the assumptions on the project environment, chronology etc., also helps defining the
system.
With these definitions it is now possible to dissect the elements of the system
within the considered perimeter.
It is important to note that elements within the system and elements in the environment can be threats-to other elements (for example, a dam breach can damage
another infrastructure) or threats-from (for example, a malevolent act on a pipe by
angry residents).
Threat-to/threat-from is a type of analysis used to link identified external or internal
hazards, for instance:
to particular targets (elements of the system) OR
from elements to targets lying outside of the system (population, environment, third
parties, etc.) or inside the system (which then become interdependent).
As a result each couple is qualified in terms of possible dire outcomes (consequences).
Highly-respected geotechnical professionals maintain that highest “risk” to “safe”
dam operation is the mill, as the mill always underestimates the amount of water
storage capacity they need for a wide variety of reasons. While directly connected,
reportedly the ability to manage contaminant levels and the longer retention times
required was found to be of most concern prior to the introduction of cyanide codes
and guidances (ICMI 2018; Cyanide Code 2017). In order to develop a study compatible with the budgeted effort, assumptions and simplifications will generally be
necessary.
The system can be described by “nodes” as shown in Fig. 8.2 where a tailings
dam is split in three nodes: crown (altitude); impervious core (percolation); and
upstream and downstream bodies (stability). Each node has incoming “resources”,
internal “processes” and outgoing “resources”, and many of the resources flows can
be bi-directional, i.e., affected by inter-dependencies.
Any mining system, no matter how complicated, can be described by as a system
of nodes whose granularity is appropriately selected. Indeed, at the beginning the
nodes may be “macro”, i.e., encompass complex processes; for example, there might
be a macro-node called “mill”. When needed the “mill” node can be subdivided into
increasing finer levels of granularity, going all the way, for example, to a node called
“tailings pump A”. The level of granularity is dictated by the stage of development (at
pre-feasibility level only macro-nodes may be necessary) and the purpose of the risk
assessment (part of the system may be modelled with macro-nodes, others be more
detailed). The advantage of scalability becomes evident as the phases of development
progress.
A well-defined system will avoid many blunders and confusions (https://www.
riskope.com/2017/07/26/three-ways-to-enhancing-your-risk-registers/) typical of
common practice risk registers.