The Tub Grinder at Work on My Farm
It's very busy and very noisy up at my compost yard - one of the most important areas on my Bedford, New York farm.
If you saw my last blog, you know my outdoor grounds crew has been gathering lots of organic debris - logs, stumps, bark and brush, and piling it all up so it can be taken to the compost yard in preparation for the tub grinder. I like to call in the massive machine once a year or once every two years, to reduce the size of our debris pile into much finer, nutrient-rich mulch. The crew and the tub grinder from Material Processors Inc. in Warwick, New York have made so much progress over the last couple of weeks.
Here are some photos, enjoy.
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- Our piles of debris get larger and larger every year. This is just a small fraction of what will go through the tub grinder.
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- All along the carriage roads around my farm are piles of organic material ready to be transported to the compost yard. It is a massive project. This pile includes large trees which had to be taken down because they were damaged or diseased.
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- There are also large piles of smaller branches and limbs taken off the trees before they are felled or picked up from the woodland floor after breaking and falling during storms.
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- For years, I’ve used a team from Material Processors, Inc. – a 30-year old company that focuses on recycling green waste, and clearing and preparing land spaces for development.
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- Here, they are using their own grapple and truck to help haul the bulky waste to the compost yard.
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- Tub grinders are extremely large and heavy, so the team delivers the tub grinder and excavator to the farm the day before to set it up and prepare it for work.
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- Tub grinders are named for the distinctive in-feed hopper – the large round tub, normally 10 to 14-feet in diameter and roughly six-feet deep. It is moved into position close to the wood pile. Before any equipment is used, all the controls are checked to make sure everything is in good working order.
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- Tub grinders have a variety of screens for the output. The screen selection for each job is usually based on the type of material being processed and the desired end-product.
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- A conveyor belt transports the finished product away from the mill and then drops it in a nearby location.
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- Here’s the tub grinder at work on the first day. The excavator is used to pick up the material using its large “jaws grab” bucket attachment to drop debris into the tub grinder.
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- Notice the small pile of ground up wood – it is very small at the start.
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- Every time I call in the tub grinder, the crew works for nearly a month grinding up all the material from around the farm. The jaws on the excavator are huge and can pick up, move and sort several large logs or pieces of debris at a time.
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- Tub grinders are loaded from the top. Here, one can see a load as it is delivered to the grinder just before it is dropped.
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- Tub grinders rely primarily on gravity to feed the material into the hammermill at the bottom of the tub. As the tub revolves, the hammermill below, shatters the wood into smaller fragments. Here, one can see the wood in the turning machine.
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- Here is the continuous discharge conveyor carrying the material away from the machine and onto a mound. It is always sad to see the trees go, but I am glad they can be repurposed into usable rich materials for the gardens. When the pile gets too large, a front loader comes to manage and move the output. This is the second week – the pile of output is much larger.
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- This output is from a first grind – only the wood. It will go through a second grind and get mixed with horse manure and organic chicken waste to create a nutrient rich mulch.
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- On the left is a pile of the horse and chicken waste.
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- After the second grind, the mound looks like this – beautiful, dark usable mulch which we use during the rest of the year to top dress the garden beds.
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- The machines do this over and over, one load at a time. There is a lot of dust and occasional debris flying around – it is very important to stay several feet away whenever visiting an excavator and tub grinder at work. The team prefers to work on rainy days, which helps to cut down on all the dust. The past few days have been perfect – on and off showers from morning to afternoon. We have a lot more work to do. I’ll be sure to share photos of the finished product.
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