The MST-JKL Automatic Cross-Belt Sampler is a heavy-duty mineral sampling system engineered by JKL Mineral Dressing S.A.C. for obtaining fully representative primary increments by means of a complete transverse cut across the entire material stream on a moving conveyor belt. The system is designed in strict compliance with the principles of equiprobability sampling and international mineral sampling standards, ensuring unbiased sample collection under continuous mining operation conditions.
1. Operating Principle
The MST-JKL performs increment extraction through a clean, perpendicular, full cross-sectional cut across the material flow transported on the conveyor belt.
During each sampling cycle:
- The cutter traverses the full cross-section of the material stream.
- The extracted increment is discharged via a lined chute to the sample receiving system or secondary stage.
- The cutting frequency is programmable and automatically controlled.
- Constant cutter velocity is maintained throughout the full sweep, preventing sampling bias.
This operating principle minimizes errors associated with:
- Particle size segregation
- Temporal grade variability
- Material settlement due to belt speed fluctuations
- Partial cross-sectional sampling
2. Main Components
2.1 Structural Frame and Housing
- Fully fabricated in ASTM A36 structural steel
- Reinforced frame for high structural rigidity
- Extra-Heavy Duty design for continuous mining operation
- Internal abrasion-resistant liners
- Inspection doors with safety interlock micro-switches
- Certified lifting lugs for safe handling
- Abrasion-lined discharge chute
Manufacturing is performed under ISO machining tolerances and industrial fabrication standards, ensuring dimensional accuracy and structural integrity.
2.2 Clean Sweep Hammer-Type Cutter
- Constructed in AISI 304 stainless steel
- Open-face cutter geometry
- Adjustable rubber curtain at the lower edge
- Side and rear scrapers
- Complete interception of the material cross-section
- Zero clearance between cutter and belt (periodic adjustment required)
The cutter design ensures:
- Full cross-sectional cut
- Elimination of under-sampling
- Reduced cross-contamination
- Minimal material spillage losses
2.3. Drive Assembly
- Three-phase gear motor, 440V / 60Hz
- TEFC (Totally Enclosed Fan Cooled) configuration
- Integrated electromagnetic brake
- Torque-controlled system to maintain constant cutter speed
- Direct shaft coupling to cutter mechanism
- Adjustable motor protection (thermal-magnetic motor protector)
2.4. Control System and Instrumentation
The MST-JKL integrates advanced electrical and control architecture, including:
- Ultrasonic material presence sensor
- Door safety interlock micro-switches
- Travel limit switches
- Main control panel
- Auxiliary control panel
- Manual / Automatic selector switch
- Mushroom-type emergency stop buttons
- Status beacon (red / yellow / green)
- Siemens S7-1200 PLC (automatic mode)
- HMI interface with dedicated screens for:
- Process monitoring
- Sampling parameters
- Alarm management
Programmable parameters include:
- Primary cutter sampling frequency
- Number of cuts per cycle
- Total cycle duration
- Interface with secondary sampler
- Feeder belt operating time
3. Bias Control and Equiprobability System
The MST-JKL complies with internationally recognized sampling theory principles, including:
- Full transverse cross-sectional cut
- Constant cutter velocity
- Regular sampling intervals
- Activation only in the presence of material
- Spillage prevention and contamination control
- Flow control according to CEMA recommendations
This design ensures:
- High analytical accuracy
- High repeatability
- Reduction of Fundamental Sampling Error (FSE)
- Compliance with ISO 12743
- Alignment with AMIRA Code P754
4. Operational Safety
The system incorporates:
- Emergency stop pushbuttons
- Door opening interlocks
- Overload protection
- Visual and audible signaling
- Alarm reset system
- Rotation direction verification prior to startup
5. Technical Advantages of the MST-JKL
- Retrofit installation on existing conveyor belts
- Easy maintenance access
- Modular engineering design
- Low maintenance cost
- Minimal internal moving parts
- High operational durability
- Imported components with local technical support
- 24/7 technical assistance
6. Applications
- Primary mill feed sampling
- Crushing circuits
- Flotation feed
- Concentrate streams
- Tailings
- Run-of-Mine (ROM) ore
- Metallurgical accounting and mass balance control
7. Strategic Value
Implementation of the MST-JKL enables:
- Truly representative sampling
- Reduction of commercial disputes
- Improved metallurgical balance accuracy
- Sampling audit compliance
- Process optimization and performance monitoring
