The Stockpile · Pile 03 — The Fix List
A silo fails two different ways, and they want different fixes. Diagnose from the ground — before anyone touches the vessel.
When a silo stops feeding, the plant says “it’s plugged” and reaches for whatever worked last time. But a silo fails in two distinct ways, and they want different fixes. Getting this diagnosis right is the difference between restoring flow and making it worse — sometimes dangerously worse.
Material forms a self-supporting arch across the outlet, like a stone bridge with the outlet as the span. Below it: nothing. Above it: the full inventory, waiting.
Flow carves a narrow channel straight down the middle, empties it, and stops. The rest of the inventory stands around the walls like a donut — compacted, stale, and going nowhere.
| Clue | Bridge | Rathole |
|---|---|---|
| How flow died | Suddenly — normal one minute, zero the next | Gradually — erratic, dribbling, starving the feeder |
| Silo weight when flow stops | Anywhere — bridge can form nearly empty or full | Heavy — most of the inventory is still standing at the walls |
| After a hammer blow or vibrator burst | May restore full flow at once (with a surge) | Brief dribble, then stops again — the channel just re-forms |
| Level indication | Reads material present above the outlet | Center probe reads empty while weight says full |
| History | Random events, worse with moisture or fresh compaction | Chronic — same silo, every time, live capacity shrinking |
Usually, yes — from the flow history, the weight-vs-level disagreement, and how it responds to a flow aid burst. Sudden total stops point to a bridge; chronic erratic flow with a heavy silo points to a rathole. The table above is the two-minute diagnosis.
Vibration compacts fine cohesive powders. On a bridge or rathole that isn't actively flowing, energy without flow just consolidates the blockage. That's the cardinal rule: flow aids assist flow — they don't create it against a consolidated mass.
The cannons aren't aimed at the channel — they're arrayed to undermine the stagnant ring at the walls, sequenced so it sloughs into the flow channel a layer at a time. Placement and sequence matter more than raw blast force.
No. Chronic plugging means the silo's flow pattern and the material's flow properties don't match. Scheduled cleaning keeps you running, and a flow evaluation — outlet, hopper angle, wall surface, flow aids — can end the cycle rather than manage it.
Our standard is whip and specialty cleaning from the top of the vessel — crew outside, capacity restored without confined-space entry. On the rare job where entry is genuinely required, it's identified in the proposal and executed under a full permit program, never improvised on site.
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