Globally, smelters separate ore from waste and non-ferrous slag is perceived as a liability. Molten slag could instead be cast into large self-annealing stone blocks and quarried as architectural products. Slag can profitably be a substitute for other products, reduce the impact of hazardous leaching and help reclaim natural habitats.
Currently, 66 million tons of slag from global non-ferrous smelting are wasted and the mining industry pays to manage this liability. Slag is poured from crucibles onto slag heaps and mining companies spend millions on insurance, lining dumps with HDPE impermeable membranes and covering slag in a custom mulch of wood fibres and glues. Slag leaches heavy metals into surface and ground waters and the metal-containing soils or sediments are transported by wind to further extend the areas of contamination. Therefore it is difficult to find a use for the granulated crush. Concerns about leaching now limit mines from selling slag and it is instead stockpiled pending future extraction of minimal residual ore. At the same time, other natural habitats are disturbed to produce 120 million tons of finished stone, immeasurable brick volume and 2 billion tons of concrete. Even though researchers have confirmed that leaching risks could be mitigated if slag is just removed from contact with water, we continue our discriminatory consumption of “valuable” materials and neglect these “waste” materials that actually retain considerable value. We need to regain the historically understood method for thriving on a whole systems approach to consumption. A key insight for our strategy came from seeing 18th century slag buildings that still stand today. They represent the potential for limiting the deleterious leaching effects of water exposure.
Molten slag from crucibles will be diverted to formwork and we will produce Corroro products. We will capitalize on the liquid state by casting large cubes near smelters. Due to a reduced ratio of surface area to volume, the cubes will self anneal into stone without the addition of any thermal energy. These large consolidated masses of material resemble granite or basalt and can be quarried down to transportable dimensions. They are subsequently taken to a fabrication site near the smelter for finer work. The slabs can be squared, honed, polished, sealed, mounted with brackets or structural joints and used for compression structures or as surfaces for steel, wood or concrete buildings. These Corroro blocks have value due to their high compressive strength, sound isolation, thermal absorption, fireproof nature, castability, hardness, low cost, and positive environmental impact. Construction with prefabricated pieces also limits waste on project sites. In developed countries, it is generally more economical to oversize blocks, pay for transportation and speed up construction time at the site as labor costs more than materials. In developing countries the blocks would be scaled down in size to suit the local technology and labor force. Further prototyping will eventually yield self splitting slabs and customizable shapes.
A proposal for the Franklin Carmichael Art Gallery then served as the agent for material reinterpretation. The high density of Corroro provides effective counterweights to support dynamic steel truss cantilevers while the weaving pattern of blocks ensures lateral stability for this compression structure.These renders illustrate the textural and monolithic qualities of the material. Diffuse and direct light is spatially contrasted to reserve the heightened perception of colour intensity for the art work being exhibited. People navigate parallel routes while light is permitted to pass perpendicularly throughout the woven mass. This tension is meant to incite the spatial qualities of the local mining culture.
LOCATION Sudbury, ON PERIOD 2011.6 - 2012.12 STRUCTURE Corroro Slabs SCALE 3 stories
CONTRIBUTIONS: ARCHITECTURE Greg Aunger, Tyler Brown, Stewart Burgess, Byron Chang, Dr. Raymond Cole, Greg Johnson, Adam Maitland, Oliver Neumann, Samuel Ostrow, Patricia Patkau, Brian Rudy CONSTRUCTION Dale Craddock, Jay Drew, Sade Kahra GEOLOGY Betsy Friedlander, Daan Maijer, Michael Parsons MINING Michael Danielson, Joseph Lawless, Ken Scholey PAINTINGS Frank Danielson FUNDING Royal Architectural Institute of Canada PHOTOGRAPHY Greg Taylor (3-unedited)