Pit pumping has begun in areas with small grains such as oats, barley and wheat. In corn-soy country producers are monitoring pit depth in anticipation of soybean harvest beginning in 6-7 weeks. With this in mind, I’ve had some inquiries regarding pit pumping and safety considerations.
The first inquiry was from a producer asking about repairing worn gating following pit pumping. His concern was the potential fire hazard associated with welding sparks serving as a possible ignition source for methane release from the pit. In his situation, the welding would be done when the barn is empty of pigs and following pit pumping.
My recommendation to him was to monitor for pit foaming. If the pit showed evidence of foaming even after pumping, don’t weld above the foam. The gas in the foam is about 70% methane and any activity which breaks the foam (such as welding sparks dropping into the pit) has the potential for release of the gas and the sparks can serve as an ignition source. If there is no foam present, turn on ventilation fans prior to welding to that any methane being released is constantly diluted below the explosive threshold level.
The second inquiry dealt with dead pigs following pit pumping. In this instance, no pigs died during or immediately after pit pumping. However 9 pigs were found dead 24 hours after pit agitation was stopped. Were the deaths related to the agitation and removal of manure?
It is tough for me to say whether the deaths were related to pumping without more details. The facility in question was a tunnel ventilation grow-finish barn. The pigs were in pens close to where the agitation device was inserted into the pit. With warmer weather and big pigs most likely the barn was in tunnel ventilation mode continuously, meaning at least 50-60 cfm/pig was being exhausted from the fans.
If the pit lid was not secured correctly following removal of the agitation device or the agitation device was left in the pit access port and the pit lid remained off, a large amount of the ventilation air was brought into the animal space from this access point. Any pit gases such as hydrogen sulfide that were being released as the pit returned to stability would have been dangerous to the pigs at the entry point.
This highlights the importance of making sure pit lids are secured once the pit agitation and pumping equipment is removed. When pumping, tarp the equipment as much as possible to limit the pit pump port as a ventilation air access point. Do not leave pumping equipment idle overnight, over the weekend, etc. in access ports without sealing the port as much as possible.