A proposed block caving gold and copper mine proposed by Australian mining exploration company Solgold, will most likely cause untold environmental harm to the region. Solgold have been working in Ecuador for over a decade and the Cascabel* mine is their flagship operation in the country. The Cascabel mine, if operational could also lead to more mines in northern Ecuador. Cascabel tenements are surrounded by Hanrine (owned by Gina Rinehart). Melbourne Rainforest Action Group and the Rainforest Information Centre have been keeping an eye on Cascabel for some time. (*Cascabel has two main ore deposits, Alpala and Tandayama. Block mining is proposed for Alpala and open pit and underground mining are proposed for Tandayama).
Rainforest Information Centre commissioned mining expert Steven H Emerman (Malach Consulting) to take a closer look at Cascabel. His detailed report can be found at this link. The Emerman report raises some key issues regarding Cascabel, some of which are highly disturbing.
Concentrate produced at Cascabel will apparently be processed on site and then transported (by truck?) 150km-200km to the Port of Esmereldas and then on to undefined refining facilities.
Some of the key issues uncovered in the Emerman report are that the substantial deposits of gold, silver and copper at Cascabel are very low grade meaning that 469 million tonnes of rougher tailings and 60 million tonnes of finer mining tailings will be created by the Alpala mine and that the costs of the tailings management have been greatly underestimated.
In Solgold’s Pre-Feasilibility Study four preferred options for managing the tailings include the most preferred option which is the construction of two seperate 57km long pipelines that will transport cleaner and rougher tailings to two unspecified sites on the coastal plains north west of Cascabel. Estimations for the costs of these options have been understated. No explanation has been given as to why the coastal plains location was chosen. Emerman writes “Considering that cost was a factor in the choice of the tailings management plan, the underestimation of the cost of tailings management comes as a great surprise”.
Two of the other possible sitings for the tailings dams would be within the Cascabel concession itself. These two options would mean the construction of tailings dams over 200 metres in height and with dam crest lengths of over 1km. The two coastal plains options would require tailings dams with heights of 190 and 132 metres with final dam crest lengths of 3.3 and 4.6km.
The Pre-Feasibility study also does not analyse the consequences of tailings dam failure. There have been 2 to 5 major tailings dam failures around the world each year over the past 30 years. The risks cannot be underestimated and what happens to the tailings dam after the mine is exhausted in 2050 and who is responsible then?
“The level of engineering complete for a TSF [Tailing Storage Facility] is greater than the level of engineering required for the rest of a mining project to support permitting requirements” (Henderson and Morrison, 2022)
“…The Pre-Feasibility Study recognises community concerns regarding the open pit and the tailings storage facility as significant risk factors. The proposed action is however “Do not publish the location of any controversial infrastructure (eg Tailings, Open Pit)…”
This is an outrageous statement. Have communities near where the mine and tailings dumps been consulted about what Solgold are planning. Why the secrecy?
In the Pre-Feasibility there is no discussion about the possibility of pipeline failure. The two 57km pipelines have to cross four major rivers and numerous tributaries and there is no discussion of the exact pipeline route in the Pre-Feasibility proposal. Emerman suggests that failures of tailings pipelines will occur every year over the 28 years of the project. (The Emerman report provides a database of 61 tailings pipeline failings, which has not been previously published). The pipelines will also require construction and maintenance of emergency ponds and leak detection systems.
There is also no discussion in the Pre-Feasibility study of excess water used in the pipelines which will most likely have to be discharged into local waterways near the tailings dam. There is also no discussion in the Pre-feasilbility study made regarding the costs of maintaining and eventual closure of the tailings dams. An estimated cost for the tailings dams is put at $267 million.. Operating costs of the tailings facility have also been underestimated by significant amounts.
Acidification of mining materials occurs when oxygen and water react to sulfide minerals to have been mined. This chemical reaction converts the sulfides to sulfuric acid. Acid mine drainage of this material is disastrous to waterways. Solgold propose to cover their tailings dams with a permanent water cover to lessen possibility of acidification of the cleaner tailings. This practice is no longer consistent with best industry practice as the water can have a detrimental impact on the physical stability of the tailings dam. Solgold believe that only the 60 million tonnes and finer grade tailings will generate acidification but is this correct?
Emerman gives the following quote in his report: “The SME Tailings Management Handbook further concurred in writing, “Where tailings subaqueous disposal is employed behind constructed dams, the dam safety liability associated with maintaining the tailings in a flooded condition also remains … A dam that retains a large water pond is inherently less safe than an embankment that does not. There are no case records of impoundments designed for perpetual submergence behind constructed dams that have been perpetually submerged. So, there is no demonstrated precedent for the legacy of permanent submergence being constructed today. We have only just started the clock” (Andrews et al., 2022).
There is no current electricity at the proposed mine site. The estimated electricity of the planned mine has also been woefully understated with multiple hydroelectric projects required to built to provide power to the mine. Because of the low ore quality at Cascabel the entire ore body still has be crushed. It is suggested that Cascabel will require around 91MW.
Cascabel’s power needs would consume all the entire output of the only two planned hydroelectric projects, Miravalle and Arenal, located near Cascabel and the Pre-Feasilibility study does not include any costings of new hydroelectric plant construction or operation. Miravalle and Arenal have a combined estimated cost of $283 million to generate 90MW. Would the Government of Ecuador support the idea that Cascabel would be the sole user of all the power generated by these yet to be built plants? No way.
The Pre-Feasibility Study also states that “Multiple hydroelectric projects are currently in the advanced planning stage, with a total capacity of 200 MW having been identified in the local area. The Project plans to participate in these projects and secure the supply of power from them” yet Solgold provide no costings estimates for these plans.
In conclusion Emerman recommends that the Solgold should abandon the project and that investors should decline to invest in the project and that regulatory agencies should not approve the mine.
