GBFI Custom Twin-Trommel
Wash Plant TT 30×12
U.S.-manufactured by Earth Construction. 38 years of heavy construction and mining equipment expertise. Engineered specifically for high-yield alluvial gold processing in tropical, remote environments.
Technical Specifications: TT 30×12
All specifications sourced directly from the official GBFI equipment manual, manufactured by Earth Construction.
Engine & Power System
| Engine Make | Isuzu C201 (4-cylinder diesel) |
| Drive System | Variable hydraulics — all functions infinitely controlled |
| Engine Life | Up to 8,000 hours with proper maintenance |
| Cooling | Oversized radiator (rated for 300 HP) + electronic fan control |
| Hydraulic Cooling | Oversized hydraulic cooler for extreme tropical heat |
| Oil Capacity | Large-capacity sump for continuous operation |
| Fuel Tank | Extra-large capacity; minimizes shutdown for refueling |
| Hydraulic Tank | Extra-large with temperature gauge and safe-range indicator |
| Auto-Shutdown | Automatic engine shutdown on low oil pressure or high coolant temp (>225°F) |
| Electrical | 12-volt onboard battery; electric front jacks |
| Engine Rebuild Kit | Under $600 (Isuzu C201) — globally available |
Processing System
| Configuration | Twin-drum (2 independent trommel barrels on 1 trailer) |
| Model Designation | TT 30×12 |
| Processing Capacity | 100 tons/day (double that of single-drum equivalent) |
| Monthly Throughput | ~2,500 tons |
| Classification | Punch plate (>½" oversize exits via conveyor) |
| Punch Plate vs Wire | Punch plate resists wear better; less oversize binding |
| Sluice Design | Multi-design riffle system (Clarkson Report hydraulics) |
| Sluice Mat Type | Vortex rubber-backed mats — thousands of traps; cleans in seconds |
| Nugget Trap | Built-in nugget trap for large gold + secondary fine-gold recovery |
| Mat Changeover | No shutdown required — one drum continues while other is cleaned |
| Chemical Use | Zero chemicals — gravity separation only |
| Water System | 3 independent valves (hopper, trommels, pan); adjustable flow |
Mobility & Transport
| Portability | Towed by standard sturdy pickup truck — no specialized transport |
| Setup Time | Less than 1 hour from arrival to operational |
| Tires | 15" highway-rated trailer tires, 10-ply radial, >2,800 lbs/tire |
| Front Jacks | 12-volt electric (onboard battery) |
| Trailer Design | All major components bolted — removable for field repair |
| Lockable Storage | Onboard lockable tool box for supplies and spare parts |
| Support Equipment | Requires 1 loader/excavator + water pump (same as single drum) |
| Loader Efficiency | Loader stays continuously productive — no idle time for mat cleanup |
Parts & Serviceability
| Parts Philosophy | No proprietary parts — all sourced globally without licensing restrictions |
| Specialized Tools | None required |
| Oil Filter | NAPA 1808 & 1802 |
| Fuel Filter | NAPA 3367 & 3336 |
| Air Filter | NAPA 2338 |
| Hydraulic Parts | Full hydraulic schematics included (valves, controls, pump, tank) |
| Grease Type | Chevron EP2 high-temp (red) or equivalent |
| Engine Oil | SAE 30W diesel engine oil; change every 250 hours |
| Hydraulic Oil | Replace annually; clean tank breather |
| Antifreeze | 50/50 mix with diesel additive (prevents electrolysis) |
| Manufacturer | Earth Construction (38 years heavy construction experience) |
| Contact | Gordon Goetsch, GBF Investments Inc. +1-210-601-0707 |
Twin Drum vs. Single Drum: The Economic Case
Earth Construction's 12-point analysis of why the twin-trommel configuration delivers superior economics for alluvial gold operations.
Purchase Price vs. Production
The twin trommel produces double the tonnage at approximately the same purchase price as a single-drum machine.
Labor Cost
One operator for either configuration. The twin's large fuel tank requires fewer shutdowns, keeping the operator productive.
Support Equipment Cost
A loader rented at $350/day loading 500 yards on a single drum yields ~$1,000 in gold. The same loader on a twin yields ~$2,000 in the same day — same cost.
Portability Cost
Delivered and set up for the same cost as a single drum. No larger truck required. Production is double.
Machinery Wear Cost
Punch plate classifying resists wear better than wire screens. One engine operates both drums. A single drum matching twin output would require two complete machines.
Parts Availability
Designed for owner-sourced global supply. No specialty tools. No proprietary design restrictions. Parts available worldwide.
Machinery Life Cycle
Isuzu diesel rated to 8,000 hours vs. gas engines at less than half that. Hydraulic drive lasts as long as the engine with proper care — no chain/sprocket wear.
Sluice Box Design
Multi-riffle Clarkson-design sluice with vortex rubber mats. Nugget trap + secondary fine-gold recovery. Mats clean in seconds vs. carpet that plugs and loses fine gold.
Water Consumption
Standard pump sufficient for twin operation in most conditions. Hydraulic drum speed infinitely adjustable for stubborn clays without additional water.
No Shutdown for Mat Changes
Shut valve, move hydraulic lever to neutral, swap mats — other drum keeps running. Loader stays productive. No idle time cost.
Idle Time Cost Eliminated
Single drums must shut down for mat cleaning — crew and loader cost continues with zero production. The twin eliminates this entirely.
Direct Cost Per Yard
The bottom line: the twin trommel delivers the lowest direct cost per yard processed of any comparable portable alluvial processing configuration.
Maintenance Schedule
Designed for remote operation with minimal downtime. All maintenance items are achievable with standard tools and globally available parts.
Daily
- Check all liquid levels (engine oil, coolant, hydraulic oil, fuel)
- Verify hydraulic oil tank valve is open before starting
- Inspect tires — check for flats
- Fuel as necessary
- Log all checks in day log
Weekly
- Check tire pressure with gauge
- Service air cleaner as needed
- Grease 4 conveyor fittings (1–2 pumps each)
- Grease hard rolls (1–2 pumps, twice per week)
- Grease axle rubber tire bearings (1–2 pumps)
- Grease pump shaft bearing (1–2 pumps)
Monthly / 250 hrs
- Change engine oil (SAE 30W diesel)
- Inspect oil condition between thumb and finger
- Consider oil analysis meter ($55) to optimize change intervals
- Check and clean all filters
- Inspect sluice mats and riffles
Annual
- Replace hydraulic oil
- Clean hydraulic tank breather
- Change antifreeze (50/50 mix with diesel additive)
- Full inspection of all bolted connections
- Replace air filter (NAPA 2338)
GBFI Equipment — Real Photos
Every image below is the actual GBFI TT 30×12 wash plant. No renderings. No stock photos.
Why This Equipment Matters to Investors
Rapid Deployment
The TT 30×12 is towed to site by a standard pickup and operational in under 1 hour. No heavy transport, no site preparation, no delay. Capital starts working within weeks of receipt.
Continuous Production
The twin-drum design eliminates the single largest cause of downtime in alluvial operations — mat cleanup. One drum continues processing while the other is serviced. No idle time. No idle cost.
Zero Chemical Liability
The entire gold recovery process relies on gravity and water — no mercury, no cyanide, no chemical reagents. This eliminates environmental liability, regulatory risk, and community opposition.
Global Parts Availability
Every part is sourced from standard global suppliers. The Isuzu C201 engine rebuild kit costs under $600 and is available worldwide. No proprietary components. No supply chain risk.
Built for Africa
Oversized cooling systems for tropical heat, punch plate instead of wire screens for abrasive laterite soils, and hydraulic drive instead of chain/sprocket — every design decision reflects real-world African operating conditions.
Scalable Platform
The TT 30×12 is designed to be replicated. As capital scales, additional units are deployed to additional locations. GBFI's platform model means the equipment can be at the highest-yield site at any given time.