Facility Closure
Issue #45: Focus on Facility Closure
Mine and facility closure trends
The field has changed a lot since SRK’s last newsletter with a closure theme, which we issued in July 2000. The above photograph illustrates one example of the current state of the practice. The graphs in this article show how some of those changes are really part of long-term trends. read full article…
Closure of Mining Pond B at Richards Bay Minerals, South Africa
In 2007 when Richards Bay Minerals (RBM) decided to close their Mining Pond B, SRK was appointed to manage the project. Prior to removing the pond and rehabilitating the pond area, the dredger had to be docked for transfer to another mining pond and the floating concentrator had to be demolished. The possibility of relocating the concentrator was also considered, but an SRK study showed that this was not cost effective. read full article…
What goes up…
The Australian mining industry is booming again! Despite the global financial downturn of 2009, mining investment continues to rise, with strong export growth in the iron ore, gold and coal sectors in 2010 and 2011. So, is it prudence or terminal pessimism that has motivated the Western Australian Department of Mines and Petroleum (DMP) to revise the Mining Act 1978 to impose more stringent mine closure obligations on mining operators and proponents? read full article…
From abandoned site to community asset
The Yankee Girl site is an abandoned tailings area located on the shore of a river in the small community of Ymir, British Columbia, Canada. Tailings periodically eroded into the river and oxidation resulted in the release of contaminants, including cadmium, lead and zinc, into a high-value fish habitat. After extensive consultation, the BC Crown Contaminated Sites Branch and the local office of SNC-Lavalin arrived at a remediation objective that would turn the area into a park-like setting for use by the local community. read full article…
Closure north of 66°
It’s another bitterly cold morning. Mine reclamation work has continued with the use of mobile light towers since the sun set for the season. A call comes in over the radio; the boom on an excavator has cracked. Minus 52°C has won the battle. The soil remediation activities will cease until spring. Closing a mine in the Arctic is no less a challenge than building one. read full article…
Land rehabilitation requirements and practices in Russia
Russian legislative requirements on closure and rehabilitation are contained in federal laws and related regulations, under titles law “About subsoil”, Land Code, law “About environmental protection”, “Instruction about the work order on liquidation and temporary closing-down of dangerous industrial projects related to the subsoil use”. A few state standards (GOSTs) also determine topsoil protection, conservation and use, and the rehabilitation of disturbed land. read full article…
Using ecological risk assessment to establish closure criteria
Does an open pit lake represent a toxic threat to wildlife after closure? If a former process pond is converted into an evapo-transpiration (ET) basin to manage heap leach and tailings drainage, does it create soil conditions that are hazardous to vegetation and soil organisms? These questions are increasingly being asked during the feasibility and permitting stages of mining projects, and the answers are guiding water management and closure strategies for mines around the world, to the benefit of the environment. read full article…
Rehabilitation and construction issues for Silvermines, Ireland
The Silvermines area in County Tipperary, Ireland comprises an area of around 5km2 plus a 74ha tailings facility. A number of abandoned open pits and underground mines were worked there, mainly from the 17th to 20th century, for lead, zinc, copper and barites with some silver. There is a legacy of health and safety issues, as well as potential mining heritage, with tourism and educational interest. read full article…
A risk-based approach to tailings facility closure
SRK recently undertook the closure design and implementation for the tailings facility at a defunct operation in central Nevada, USA. The facility stored gold cyanide tailings in three individual cells of differing heights and construction. Initially, SRK needed to access and review all the as-built records and the facility’s annual operational report as there was limited knowledge of cell design and condition. The operation had been defunct for a number of years and portions had been designed by three different engineering consulting companies. read full article…
San Manuel, Arizona: from mining to reclamation
The San Manuel property is a former integrated mining, milling and smelting operation located in central Arizona, USA. Large-scale mining activities started with underground block cave operations in the 1950s. In the mid-1980s, mining was expanded to include a surface heap-leach facility and an in-situ leach operation within the active cave area. Seven miles to the south, the mill, smelter and refinery processed ores from the San Manuel mine. read full article…
Mine closure planning in the Chinese mining industry
SRK stands at the forefront of mine closure planning in the Chinese Mining Industry. SRK China has completed numerous Independent Technical Reviews (ITRs), covering stock exchange listing, acquisition and/or financing for both domestic and internationally based mining projects. Through this due diligence process, the Chinese Mining Industry is adopting international standards and management practices, incorporating mine closure planning. read full article…
Mine closure regulation in Turkey
The “Regulation on Reclamation of Lands Disturbed by Mining Activities,” published in December 2007 and amended in January 2010, is a milestone toward establishing requirements for mine closure planning in Turkey. It requires that reclamation plans for mining projects be appended to the Environmental Impact Assessment (EIA) reports. The regulation provisions do pose general mitigating actions, such as post-mining safety of the land and acid rock drainage prevention and mitigation, but the process is still in its infancy and shows some limitations. read full article…
Demolition costing
An integral part of any facility closure is estimating the cost of removing the mine infrastructure that cannot be used for other purposes. This cost, while considerable, usually forms a smaller portion of the total closure liability. The approach taken in assessing demolition costs depends on the level of information available. New mines can usually provide drawings and schedules of quantities for the infrastructure, whereas older mines, at best, only retain surface layout plans. read full article…
Capital expenditure to reduce long term closure liability
SRK Reno recently designed and permitted a flotation tailings disposal impoundment in Nevada. The conceptual engineering design envisioned traditional grading, embankment construction, and a single synthetic liner overlain by a drainage system with a gravity outfall passing through the synthetic liner into a lined collection pond. In addition, the conceptual design required incorporating a diversion channel for upstream stormwater to accommodate 1-in-100-year, 24-hour peak flows for the regulated minimum design criteria. read full article…
Reducing economic impacts from interim closure
Interim or temporary closure can be defined as the cessation of the operation of a mine, or a mining or processing activity, as a result of a planned or unplanned activity. Cessation of operations can be precipitated by a number of factors such as a drop in commodity price, seasonal closures, unforeseen weather events, a failure in a major processing plant component, labor disputes, agency shutdowns, or litigation. Planned or unplanned temporary closure does not release an operator from their compliance obligations. read full article…
Soil covers for cold region mine closures
Soil covers are widely used in the closure of tailings and waste rock. However, current soil cover practices are based on experience from temperate regions, and on the theoretical basis provided by agricultural soil physics, which is also derived largely from studies in temperate zones. Two recent research projects led by SRK’s Vancouver office identified several dozen “cold region” processes with the potential to significantly affect soil covers in high latitude or high altitude locations. read full article…
How did the International Cyanide Code get started?
In response to public concern about environmental impacts from gold mining operations, the mining industry set up a stakeholder group under the United Nations Environmental Program to address prevention planning. The group developed a certification program to demonstrate responsible management of cyanide, protection of human health and prevention of environmental impacts. Companies comply with a set of nine principles related to cyanide handling and use, and must pass periodic audits. read full article…
Closure planning to comply with the International Cyanide Code
About 10 years ago, a multi-stakeholder group created a system that demonstrates a company’s voluntary commitment to environmental standards under the International Cyanide Code. Companies certified under the Code (referred to as Signatories) have publically committed to comply with its requirements and have demonstrated that their business is environmentally responsible. Principle 5 of the Code concerns decommissioning and addresses the issue of closure, which was often overlooked or underfunded by the mining industry in the past. read full article…
Engineering solution to save Pacific salmon in the Tsolum River
In partnership with local communities, the BC provincial government and local industry, SRK developed a long-term solution to control copper-bearing drainage that has been contaminating the headwaters of the Tsolum River for decades. The objective of the project was to improve water quality, return salmon, steelhead and cutthroat trout to local waters, and support the goal of sustainable BC fisheries. After briefly operating from 1964 to 1966, the Mount Washington copper mine has been a major source of acid rock drainage (ARD) entering the Tsolum River near Courtenay, BC. read full article…
Using abandoned mines as field laboratories
SRK Cardiff and Cardiff School of Engineering are collaborating to characterise the impacts associated with mine waste at historical sites in central Wales, stretching back over 800 years. Our study will systematically collect representative mine waste samples from historic mine dumps. Working with industrial archaeologists, the dumps will be dated. Samples will be subjected to a range of diagnostic leaching and characterisation tests and compared to fresh, unweathered wall rock from underground. read full article…
The Environmental Management Plan and closure planning
During 2009, SRK Johannesburg completed a number of environmental compliance audits as part of due-diligence exercises. These reviews showed that closure planning is frequently limited to strategies presented in an Environmental Management Plan (EMP). These EMPs are generally prepared during authorisation, years before mining and decades before closure. Once developed, these plans are seldom revisited for appropriateness. In SRK’s experience, closure requirements tend to focus on returning the site to some land capability that existed before mining. read full article…
Closure cost confusion
The last two decades have seen a significant evolution in both the methods and purposes for estimating closure costs. As part of this evolution, changes in how closure cost estimates are used have resulted in coincident changes in the scope, methods employed, and level of detail required. Before regulatory requirements were developed, closure cost estimates were typically intended for the planning, design, and contracting of the actual closure, and were often developed late in the mine life cycle. read full article…
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