The late Keith Bolsen said many times that a key goal of making good silage is sending all workers home safely to their families at the end of each day. To meet this goal, producers must design their facilities and equipment to protect workers and must implement practices to keep workers safe

Crush – Workers are exposed to being run over by equipment during filling of bunker/pile silos as transportation equipment and filling and packing equipment are continuously moving at the storage. Visitors, especially children, should be excluded from the work area. Equipment should be equipped with backup warning signals to warn workers. Workers should be instructed to remain in their vehicles so they are not exposed to moving equipment.

Use safety clothing to make workers more visible to equipment operators. When working at night, site lighting and equipment lighting give equipment operators good visibility of the area.

Collision – When multiple pieces of equipment are moving in a work area, the chances of a collision increase. To avoid collisions, a series of procedures should be established to give specific equipment a right-of-way over another. Equipment operators should use devices to communicate with other operators so they know what will happen next. Care must be used to prevent communication devices from becoming a distraction, as they might be used for alternative conversations.

Dump trucks in particular (but walking floor trucks also) discharge their loads quickly. Workers should be instructed to stay away from the rear of discharging trucks to avoid being engulfed by forage.

Driving off the wall – Filling and packing tractors run the risk of driving off the wall top of a bunker silo. Packing tractors require a rollover protection cage and operators must wear seatbelts. To avoid driving off the wall, operators should slope the surface of the forage down away from the wall top until it is time to place and pack the forage above the wall top. Slope forage up away from the wall starting at some distance (several feet) away from the wall.

Locating a siting fence along the top of the wall gives the tractor operator a better sense of where the wall top is at all times. The siting fence can also act as a barrier against workers falling off the wall.

Rollovers and tip overs – As the slope of the forage surface increases, so does the likelihood of equipment driving on this surface rolling or tipping over. Limiting surface slopes to 3 units of horizontal run to 1 unit of vertical rise (3-1) reduces the risk of rollover or tip over. If a slope is greater than 3-1, equipment should back up the slope and drive forward down the slope to avoid a tip over.

Dump trucks experience an increased risk of tip over when they drive on a non-solid surface like forage and/or when the wind is blowing while the box is up. Avoid using dump trucks to transport forage during windy conditions. Truck drivers should keep dump trucks on solid surfaces, especially when dumping.

Covering the pile – During the forage covering process, workers are at risk of falling off the wall of bunker silos. Workers should be aware of where the wall is at all times. Facing the wall while working helps maintain this awareness. Wind can move the covering plastic with great force. Assign enough workers to maintain control of the plastic so no one is carried off the bunker/pile by the wind.

Covering plastic, especially when wet, is very slippery. Keeping the forage slope at 3-1 reduces the likelihood of sliding down the slope. Slip-resistant footwear helps reduce sliding down the slope as well.

Steel-belted tire sidewalls can have sharp pieces of wire projecting from the cut edge. Use leather gloves to protect hands from cuts and punctures when handling steel-belted tire sidewalls. These pieces of wire are also likely to puncture the plastic, which contributes to silage spoilage from oxygen exposure.

Handling heavy cover-weighting materials (gravel-filled bags and tires) can cause muscular and skeletal injuries if not performed properly. Moving weighting materials as close as possible to the application site with equipment helps reduce the amount of effort required to handle the weights. Workers should use proper lifting practices to avoid injuries. Use legs for lifting rather than the back. Hold the weight close to the body. Avoid twisting with a weight to avoid back injuries. When needing to turn, rotate the whole body using the legs.

Silo gas – Within the first few weeks post filling, silo gas can be present. Wind usually ventilates silo gas from the area around bunker/pile silos, but there are cases when silo gas can accumulate to dangerous levels. Avoid confined spaces between and near silos to reduce possible exposure to silo gas soon after filling.

Avalanche – Most bunker/pile silos are emptied in such a way as to leave a vertical feedout face. Silage behind these faces is known to slough off creating avalanches. Avalanches occur suddenly and often without warning. Sometimes fissures appear at the top of the silage before an avalanche happens. Avalanches pose a risk to anyone present in the hazard zone in front of the feedout face. Avalanching silage has engulfed workers causing severe injury and death. Some avalanches are so large that loadout equipment has been engulfed trapping the operator inside.

Because of the severe consequences from avalanches, workers should not be on foot on the silo floor or on top of the silo surface within the hazard zone (considered to be three times the height of the feedout face). Using good covering and weighting practices limits top surface spoilage; with low top spoilage, workers need not spend time forking spoiled silage near the feedout face.

Those needing to sample silage should remove the silage from the floor with a front-end loader and carry it away from the hazard zone before taking samples. Some producers run several bucket loads of silage through a feed mixer before sampling to obtain representative samples. This whole process should be conducted outside the avalanche hazard zone.

Several factors increase the likelihood of an avalanche. Feedout equipment that cannot reach the top of the feedout face leaves a silage overhang. Eventually, the overhang collapses onto the floor. Design bunker/pile silos with a height no taller than the equipment used to unload them can reach.

Building bunker/pile silos that are very tall increases avalanche likelihood, as pressure causes a blowout from the silo face with a subsequent slide of silage from above. It is not known how to predict the maximum height to limit avalanches, but if you are experiencing avalanches, reducing the height of new silos should reduce the frequency of avalanches.

When new forage is packed against an existing feedout face, a discontinuity in the silage mass occurs. Producers report that avalanches of the newer silage often occur at these interfaces. One way to avoid the likelihood of an avalanche at this discontinuity is to shape the old silo feedout face at a slope of 3-1 before placing the new forage.

Higher-moisture silage has a higher rate of seepage, often seen as leachate draining along the silo floor. As this seepage drains into the lower portions of silage, saturation is reached. The seepage lubricates the silage causing it to slide and resulting in an avalanche. More avalanches occur in corn silage than hay silage due to the higher moisture content of corn silage. Removing a large area of plastic silo cover exposes silage to an increased amount of rainfall, which can add to the seepage percolating through the silage. This can increase the possibility of an avalanche.

Vibrations from operating equipment or earthquakes can also trigger an avalanche.

When combinations of the above factors occur, the probability of an avalanche increases.

People working to fill and feed from bunker and pile silos need to be aware of these hazards and protect themselves so they can go home safely to their families at the end of each day’s work.

Information on making silage safely is found at the Keith Bolsen Silage Safety Foundation website.