First and foremost…. We do not want to see these kinds of emissions from our operations. We do everything in our power to avoid them and we are committed to improving. That’s how we approach all aspects of our business. To that end, a team has analyzed and reviewed all available technical options to reduce or eliminate impacts of excess hot metal management, and information about the practice and options was presented to the company’s Community Liaison Committee in April 2016. The review and file preparation for new technology continues and we will have a plan shortly for additional technology to address this issue. In the meantime, we have implemented a running reline strategy to reduce the volume of excess molten iron generated during KOBM relines which in turn reduces the need for excess hot metal management. During a KOBM reline (where the refractory lining inside the furnace is replaced), the production of molten iron is carefully controlled to minimize the creation of excess hot metal. In addition, a Standard Operating Procedure (SOP) has been developed for excess hot metal management to allow for proactive management of the key causes of emissions.
In terms of the background… Excess hot metal management is the pouring of liquid iron into slag beds. The liquid iron is generated in the company’s Blast Furnaces and is normally transferred to either the electric arc or basic oxygen steelmaking furnaces as part of the steelmaking process. There are times when there is more molten iron produced than can be accepted by steelmaking (not all the time but for example when a steelmaking furnace is not operational). In these cases, the iron is poured onto slag beds. The sudden release of water vapour may occur when the iron is poured quickly, the slag bed is compacted too tightly, there is excess moisture in the bed or slag, or when there is overflow from the slag bed onto the ground. Visible emissions tend to happen more frequently after rain events, when the slag bed area is wet.
In the case of this weekend, there was a crane failure in our basic oxygen furnace steelmaking stream. As a result, the hot metal excess management process had to be implemented very quickly. At the same time, there were significant rains which made the beds wet and difficult to manage.
Of course with such visible emissions, there is a requirement to ensure there is no immediate danger to members of the community. These types of emissions are primarily composed of particulate matter, mostly iron, silica, calcium and magnesium. Trace elements include aluminum, phosphorus, manganese and titanium, while the remainder of substances in the emitted particulate matter are burned carbon and water vapour aerosols. The potential health effects from the emissions from excess hot metal management are low as the particulate matter within the excess hot metal management emission is typically a large particle size, which limits the potential for inhalation, and therefore means that there is less potential for an impact to human health.
Regardless, again we do not want to see these kinds of emissions from our operations. We do everything in our power to avoid them and we are committed to improving.