24-MMP-A6 Mining and the Environment · December 2014
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Mining and Mineral Processing Engineering, 09-MMP-A6 Mining and the Environment, 2014-Dec. 3 hours duration, open book (any non-communicating calculator permitted). Six questions of equal value (20 marks each) constitute the bank; a candidate answers any FIVE, with only the first five questions appearing in the answer book marked. Most questions require an essay-format or point-form answer.
Reference texts: BC Ministry of Energy, Mines and Low Carbon Innovation, Health, Safety and Reclamation Code for Mines in British Columbia (current edition) (permitting, reclamation and closure planning requirements); Canadian Dam Association (CDA), Dam Safety Guidelines (2013/2019 update) (dam classification, tailings dam consequence categories, freeboard/PMF design basis, dam safety review and inspection intervals); Global Industry Standard on Tailings Management (GISTM, 2020) (tailings governance, design and closure principles); Price, W.A., MEND Report 1.20.1, Prediction Manual for Drainage Chemistry from Sulphidic Geologic Materials (1997/2009) (acid-base accounting, neutralizing potential ratio screening criteria); International Network for Acid Prevention (INAP), Global Acid Rock Drainage (GARD) Guide (ARD prediction, prevention and treatment across the mine lifecycle); Vick, S.G., Planning, Design, and Analysis of Tailings Dams, 2nd ed. (upstream/centreline/downstream embankment construction methods); Government of Canada, Metal and Diamond Mining Effluent Regulations (MDMER, the current name for the exam's "MMER") under the Fisheries Act; Government of Canada, Impact Assessment Act (successor to the 2012 Canadian Environmental Assessment Act); Mining Association of Canada, Towards Sustainable Mining Tailings Management Protocol; International Cyanide Management Institute, International Cyanide Management Code.
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
| # | Statement | Answer | Explanation |
|---|---|---|---|
| a) | Mineral and mining rights fall under federal jurisdiction in Canada. | False | Under ss. 92A and 109 of the Constitution Act, 1867, ownership, management and disposition of Crown minerals within a province are provincial powers – each province administers its own mineral tenure, leases and mining permits. Federal jurisdiction over minerals is the exception rather than the rule, limited to the territories, federal/reserve lands, uranium and some offshore areas. |
| b) | Federal environmental approval is required for most mining projects in Canada. | False | A federal impact assessment under the Impact Assessment Act (successor to the 2012 Canadian Environmental Assessment Act) is triggered only when a project meets a prescribed capacity or physical threshold on the Physical Activities Regulations (e.g. a new metal mine above a stated ore-processing rate). The great majority of mining activity in Canada – exploration and many smaller operations and expansions – proceeds through provincial environmental assessment and permitting alone, so federal review is the scale-triggered exception, not the norm, even though most LARGE metal mines do trigger it via this threshold or via a Fisheries Act/MDMER Schedule 2 listing. |
| c) | Mine sites in Canada are not allowed to discharge effluent to the environment. | False | The MDMER (the exam's "MMER") is a permission-with-limits regime, not a prohibition: a mine listed on Schedule 2 may deposit effluent (including tailings) to a fish-frequented water body provided it meets prescribed authorized concentration limits for substances such as arsenic, copper, lead, nickel, zinc, un-ionized ammonia, total suspended solids and radium-226, and undertakes an Environmental Effects Monitoring (EEM) program. |
| Term | Definition |
|---|---|
| Hazard | A source of potential harm, damage or loss – for example a tailings dam breach, an underground mine gas outburst, or an unstable pit wall – considered purely as an event that COULD occur, independent of how likely it is. Identifying hazards is the first step of any risk assessment, before likelihood or consequence is estimated. |
| Consequence | The outcome or severity of harm (loss of life, environmental damage, financial or reputational loss) that WOULD result if a given hazard event actually occurred. Risk is conventionally expressed as a function of likelihood and consequence, $\text{Risk} = f(\text{Likelihood}, \text{Consequence})$, and it is exactly this consequence classification that the Canadian Dam Association uses to set a tailings dam's design flood, design earthquake and inspection frequency (Question 6b). |
| Plasticity index | The numerical range of water content over which a fine-grained soil behaves plastically: $PI = LL - PL$, where $LL$ is the liquid limit and $PL$ the plastic limit. For example, a tailings sample with $LL = 42\%$ and $PL = 24\%$ has $PI = 42 - 24 = 18\%$; a high PI indicates a highly plastic, compressible, low-permeability clay, while a PI near zero indicates a non-plastic silt or sand more prone to liquefaction (Question 6a). |
| Atterberg limits | A set of standardized water-content boundaries – the shrinkage limit, plastic limit (PL) and liquid limit (LL) – that mark the transitions of a fine-grained soil between solid, semi-solid, plastic and liquid consistency states, determined by the Casagrande cup/fall-cone (LL) and thread-rolling (PL) tests. They are the standard classification framework for tailings and foundation soils and the basis of the plasticity index above. |
| Darcy's Law | The governing equation for laminar seepage flow through a porous medium: $q = -k\,\dfrac{dh}{dx}$, where $q$ is the specific discharge, $k$ the hydraulic conductivity of the material and $dh/dx$ the hydraulic gradient. It is the physical basis for locating the phreatic surface within a tailings embankment and for calculating the seepage quantity a collection ditch or underdrain must handle (Question 5c/5d). |
Metal Mining Effluent Regulations (MMER, now the Metal and Diamond Mining Effluent Regulations) under the Fisheries Act. Governs the deposit of mine effluent (and, via Schedule 2 listing, tailings) into water frequented by fish, setting authorized concentration and mass limits for key deleterious substances and mandating an Environmental Effects Monitoring program to confirm the receiving environment is actually protected. The operator must design, build and operate a treatment system capable of meeting the limits, self-monitor continuously, and report to Environment and Climate Change Canada; engineering staff are responsible for the treatment plant design and the EEM sampling program. The federal government (ECCC, backed by DFO's habitat-protection authority) inspects, audits EEM cycles and can prosecute under the Fisheries Act, which carries some of the most severe penalties in Canadian environmental law, including significant fines and, for corporate officers, personal liability.
Canadian Dam Association (CDA) – Dam Safety Guidelines. A voluntary technical guideline (not a statute) that classifies dams, including tailings dams, into consequence-of-failure categories and specifies the corresponding design flood and design earthquake return periods, inspection frequency, and the interval for an independent Dam Safety Review (Question 6b). The operator's engineer of record is responsible for the dam safety management system and the Operation, Maintenance and Surveillance (OMS) manual; there is no CDA enforcement mechanism, but most provincial mines regulators now incorporate the CDA guidelines by reference into permit conditions, giving them the practical force of law even though the document itself remains voluntary.
Mining Association of Canada (MAC) – Towards Sustainable Mining (TSM) Tailings Working Group. A voluntary, MAC-member-mandatory framework whose Tailings Management Protocol requires each facility to name an accountable executive, maintain an OMS manual, conduct regular dam safety inspections, and publicly self-assess and report performance on a graded scale, verified by an independent third-party audit every three years. The mine operator implements the protocol and its engineering staff execute the OMS program day to day; MAC administers the verification and publishes the results, but its only real sanction for non-conformance is reputational and membership-based – it has no statutory power, though lenders applying the Equator Principles increasingly cross-reference TSM conformance.
International Cyanide Management Code for the Gold Mining Industry. A voluntary certification program for gold operations that use cyanide in processing, covering the full cycle from production and transport through on-site use to decommissioning, and requiring an independent triennial audit with public certification results. The operator commits corporately and funds the audits; engineering staff implement the cyanide management plan, including worst-case-discharge tank design and spill contingency planning. The International Cyanide Management Institute administers certification (and can suspend or revoke it) but has no government enforcement power – certification is nonetheless frequently a practical precondition for project financing, insurance and, in some jurisdictions, permitting.
