Following breaches of a tailings pond and reservoir at two large-scale mining companies, Minister of Natural Resources Vickram Bharrat has announced that a joint-agency monitoring unit will be established.
“This is the second time we have had a collapse; first it was Bosai and now GMI [Guyana Manganese Inc]. So I wrote the GGMC to set up a joint team with the EPA and others to monitor these large scale mining companies,” Bharrat told the Sunday Stabroek as he emphasised that the country cannot risk a third mishap. Bosai and GMI have the same parent company.
Two weeks ago, a section of the reservoir belonging to Chinese-owned GMI collapsed, releasing a torrent of water that washed away a section of the road which connects Matthews Ridge to Port Kaituma, and flooded surrounding areas.
Region One Chairman Brentnol Ashley has stated that a compromised drainage system is suspected to be the primary cause of the collapse. Ashley said that from all indications, the company did not change the drainage pipes that were laid years ago. The integrity of the pipes, he said, is believed to have been compromised by the volume of water in the reservoir.
The Natural Resources Minister said that on hearing of the collapse he was deeply concerned and that a team of persons from his ministry along with personnel from the Guyana Geology and Mines Commission (GGMC) and the Environmental Protection Agency (EPA) were swiftly dispatched to the area.
EPA Director Kemraj Parsram had told this newspaper that assessments done by the Agency found that the water in the reservoir exceeded the capacity of the structure, resulting in part of it collapsing. He said they also found that here was no proper monitoring system in place.
The EPA warned the company that the deficiency must be addressed and they must improve on the monitoring aspects of their operations, Parsram said.
He explained that processed water goes into a tailings pond which is separate from the reservoir, hence it is believed that the reservoir contains nothing but pure fresh water. However, Parsram said when the team visited the area, they collected samples of the water to test for contamination. That process, he noted, will take some time.
Engineer Charles Ceres had the week before the collapse, emphasised to the Sunday Stabroek that large mining companies needed to have proper risk analyses and oversight plans and stick to the guidelines they had proposed in their project submissions and Environmental Impact Assessments (EIAs).
He had pointed to the spill last year from Bosai’s tailings pond, and the severe flooding caused by a breach of the tailings pond at the East Montgomery Mines in June this year, saying that had there been ample risk plans and proper execution of them, the setbacks to the neighbouring communities would not have occurred. He had warned that there needed to be oversight by the EPA and the GGMC.
Two days after Ceres’ interview with this newspaper, the reservoir at GMI collapsed.
Sequences
The veteran geo-technical engineer had explained that risk management refers to the integration of business needs with environmental compliance in the everyday decision making and operation of a company. He said that event sequences and potential incidents are dictated by the environment in which the project is located. These are related to things such as the site locations and meteorological conditions, among others.
Ceres noted that Guyana has several distinct physiographic areas; the coastal plain, sand and clay belt, (White Sand Series), the pre-Cambrian crystallines and the Pakaraima Plateau, and this must be factored into every analysis. The exposure scenario for groundwater contamination, he noted, will differ for each area.
“Typically, groundwater contamination has a relatively remote possibility of being realised in the coastal plain due to the presence of excessive thicknesses of clays at the ground surface. There is however evidence that some chemicals can interact with clays to make them more permeable. Clays tends to have high cation exchange capacity, however during substitution the matrix may become more pervious…. The White Sand Series is the recharge zone for potable water on the coast. This therefore creates a potential pathway for groundwater contamination. In the rock formations of the Pre-Cambrian crystallines and Pakaraima formation, groundwater flow would be dictated by joints in the rock and the rock mass permeability as opposed to the porous media flow in the white sand series and coastal plain,” he explained.
He said that while some might think his advice and “talkings” are not necessary, a comparison of similar operations globally would show the importance of what he is saying.
“Baseline data should establish parameters to enable the potential for groundwater contamination to be assessed. This data should include geohydrologic data such as groundwater levels, flow gradients, hydraulic conductivity, adsorption coefficients, dispersity, and porosity and so on. These parameters are critical to an effective assessment of the fate and transport of chemicals released to groundwater,” he said.
‘The fate and transport of contaminants in groundwater can be assessed using either analytical or numerical models. The database has to be adequate to ensure the validity of any fate and transport technique used. This database is sorely lacking in Guyana and the regulatory agencies should focus on development of these databases to allow for defensible assessment of fate and transport of contaminants in groundwater,” he added.
Tailings ponds here, he said, must be designed to ensure stability of its embankment. “Stability analysis must be performed of the embankment cross-section to optimize the structure with respect to cost and other objectives while maintaining reliability. Flow nets and appropriate numerical methods will be used to estimate seepage direction and volume and pore pressures at points within the embankment. A flow net is a graphical solution of Darcy’s law to show steady flow through porous media and is used to show ground water flow. Finite-element and other analyses are also appropriate for predicting seepage direction and volume. The analyses of the tailings pond embankment stability will considers a host of modes.
These modes include slide, overtopping, foundation failure, erosion, piping and liquefaction.
According to Ceres there must also be frequent monitoring as it is integral and will depend on previous observations and on “the critical nature of the parameters”. “The frequency of monitoring must be more pronounced during and immediately after construction, he said, but after records indicate that conditions are relatively stable, the frequency of monitoring could decrease.
Integral and tied into risk analyses and monitoring, should also be an emergency response plan and a Spill Prevention and Cleanup Contingency Plan submitted by the company.
“The objective of the Emergency Response Plan (ERP) is the protection of the communities and the environment in the project area of influence through the development of emergency response strategies and capabilities. This Emergency Response Plan details measures to respond to potential releases of tailings, process chemicals, process wastewater, fuel oils and or other hazardous material. In addition, it details emergency response procedures for potential release of hazardous material which is being transported to the site,” he said, using excerpts from a plan he had written.
“Examination of a project identifies several possible scenarios which may require the activation of emergency response procedure. Emergency response actions will be needed for different situations such as spills of fuel oil, cyanide or other hazardous material during road transport to the site, releases of fuel oil, cyanide or other hazardous material during unloading and mixing, releases of fuel oil, cyanide or other hazardous material during fires and explosions, release of fuel oil, cyanide or other hazardous material due to pipe, valve and tank ruptures, overtopping of tailings and water management ponds, failure of embankment of the tailings and/or water management pond, power outages and pump failures and uncontrolled seepage through the embankment of tailings and or water management pond and so on,” he added.
He believes that with ample oversight from the GGMC and EPA, large scale mining companies would be less likely to be lax in their internal management.
“These are factors which must be incorporated into the design of these facilities along with mandatory emergency response procedures. Companies’ failure to implement these measures and lack of oversight is what causes these incidents and you put people’s lives at risk and them having to climb trees for safety and refuge,” Ceres emphasised.
According to the Minister of Natural Resources, the motoring team, when established, will help to ensure that there are no future occurrences of spills and breakage of dams at mining facilities across the country.
