In a year met with unique corn harvest and storage issues, paying extra attention to grain bin safety is a priority, says Matt Roberts, Purdue University Extension grain storage specialist.
"The biggest grain bin safety concerns this year are related to moldy corn," he adds. "The molds we are concerned about develop when corn is stored too wet—greater than 15 percent moisture-- and also can develop if moisture enters the storage structure through leaks or downspout condensation.
Kernels damaged by the field molds were abundant in last year’s crop, as well as broken kernels and fine materials that resulted from high harvest moistures, are more susceptible to storage mold growth than are healthy, undamaged kernels.
Damaged and moldy grain often clumps together and can clog or create other in-bin issues that require farmers’ attention. Roberts reminds that those activities need to occur from outside the bin, if at all possible.
"As moldy corn is drawn out of the bin, it can clump together and clog the center well, requiring the farmer to find a way to break up the clumps," Roberts notes. "The danger is that farmers may be tempted to enter the bin to try to rectify the situation."
Molds also can cause corn to bridge across the top of a bin.
"Often moldy corn crusts at the top, and when a farmer goes to unload the bin, the crusted grain causes a bridging phenomenon," Roberts says. "If the grain has been drawn out from under the crusted layer and a farmer walks on top of that grain, the bridge can collapse and the farmer can become entrapped under that grain."
Corn molds can cause grain to stick to the sides of the bins. The safety concern then occurs when a farmer climbs into the bin to try to probe the stuck grain from underneath. In this scenario, when grain does break loose, it can avalanche, also entrapping the farmer.
"We recommend that farmers try to probe clumps - both on the walls and in the center well - from the outside of the bin," Roberts said. "However, if a farmer decides to enter a bin he needs to make sure all of the equipment, including augers, are not only turned off, but also locked out in case someone showed up to unload the bin without knowing someone is inside.
"It's also essential to have an observer outside of the bin to monitor what's going on outside and to keep an eye on anyone inside the bin."
Richard Stroshine, Purdue agricultural engineer, adds that in the case of clogged bins, a farmer should avoid opening side wells for fear of bin collapse. "What happens is that creates an unbalance of forces in the bin, and if farmers start drawing corn from the side well it can actually cause the bin to buckle,” he notes. "There is some equipment for loosing up bins. If a farmer finds himself in a really difficult situation, contacting one of the companies that makes such equipment can help determine how best to solve the problem."
Safety harnesses are another way a farmer may try to increase grain bin safety, but Roberts says most bins are not designed to hold farmers from inside the bin with a harness. "Farmers who have harnesses need to make sure they are approved for grain bin use, and they need to be aware that other than helping rescuers locate them in an emergency situation, harnesses don't really help with entrapment," he says. "Harnesses should definitely be used when you are working up high, outside the bin, to prevent falls."
Managing aeration correctly and monitoring bin conditions can reduce some of the safety concerns. "Farmers should check their bins every two weeks," Roberts notes. "We recommend they let the fans run for about five minutes, then climb up, open the door and smell for mold. If you are warming grain as the outside temperatures rise, make sure not to exceed 50 F, because anything higher is going to promote mold and insect growth."
More information is available on the Purdue Extension "Managing Moldy Corn" Web site.