ZOOMRY
In Guizhou Province, an open-pit factory focused on coal processing and transshipment has faced challenges due to continuous capacity expansion in recent years, with daily coal stockpiling increasing from 8,000 tons to 12,000 tons. The traditional “loader + fixed stacker” stockpiling model has become increasingly inadequate to meet production demands, revealing multiple bottlenecks: fixed stackers can only operate in one direction, with a single unit handling less than 300 tons per hour, failing to match the factory’s coal receiving capacity of 450 tons per hour, resulting in frequent coal accumulation at the unloading area. The stacking height is limited to 8 meters, and the 54-meter-long stockpiling area can only accommodate 60,000 tons of inventory, necessitating frequent transfers to temporary stockyards, which further exacerbates material losses. Open-air stockpiling leads to dust emissions of 22 mg/m³, far exceeding the 10 mg/m³ limit set by the Comprehensive Emission Standard for Air Pollutants, triggering persistent complaints from surrounding areas. Coal dust dispersion and transfer processes contribute to a coal loss rate of 5%, highlighting significant material waste. The stockpiling area has a natural 12° slope, which fixed stackers cannot adapt to, requiring additional site leveling costs. During the rainy season, water infiltration causes coal caking, impacting subsequent processing and accelerating equipment corrosion, with annual maintenance frequency exceeding 12 times and persistently high operational costs.
To address these challenges, the factory requested suppliers to provide a coal stockpiling solution that is “highly efficient, environmentally sealed, and adaptable to site conditions,” with full integration of equipment for the “coal receiving-feeding-stacking” process to ensure seamless connection with the existing production chain. ZOOMRY, combining on-site survey data (terrain, weather, coal characteristics) with its comprehensive product line parameters, designed a full-chain solution centered on a radial telescopic stacker, complemented by a truck unloader and a hopper feeder. This solution leverages the functional advantages of each piece of equipment to create a seamlessly integrated “receiving-feeding-stacking” stockpiling system.
Project Requirements
The factory’s requirements revolve around four key dimensions: “precise parameters, system integration, site adaptability, and compliance reliability,” precisely tailored to the characteristics of open-pit coal stockpiling. In terms of parameters, the core stockpiling equipment must achieve a handling capacity of ≥450 tons per hour, a belt width of 1200 mm, cover a 54-meter stockpiling length, and adapt to a 12° natural slope, with radial rotation and telescopic functions. For system integration, supporting equipment for coal receiving and feeding is required to form a closed-loop process of “truck unloading-uniform feeding-efficient stacking.” For site adaptability, the equipment must withstand open-pit conditions, including high temperatures (40°C), low temperatures (-5°C), and rainwater, with core components having a protection rating of ≥IP55. For compliance and maintenance, dust emissions must be ≤10 mg/m³, the equipment’s overall service life must be ≥15 years, and operational training and spare parts support must be provided.
Based on these, the project set four key objectives: a stable stockpiling system handling capacity of ≥450 tons per hour, with the 54-meter stockpiling area’s inventory capacity exceeding 80,000 tons; dust emissions ≤10 mg/m³ and coal loss rate <1%; equipment adaptability to a 12° slope with a coal caking rate during the rainy season of ≤1%; and a 30% reduction in annual maintenance costs, with initial investment offering a cost-performance advantage over international brands.
mobile stacker Coal Stockpiling Solution
Core Equipment
To meet the 450-ton-per-hour coal stockpiling demand, ZOOMRY selected the ZR120SF radial telescopic stacker, which adheres to the ZR-SF series technical standards and is specifically optimized for open-pit conditions.
Stockpiling Efficiency and Capacity
The ZR120SF radial telescopic stacker features three adjustable functions: “radial rotation + telescoping + luffing.” It offers a radial rotation angle of ±120°, a telescopic range of 10–22 meters (covering the entire 54-meter stockpiling area), and a luffing angle range of 0–18° (adapting to the site’s 12° natural slope without additional leveling). With a PLC-controlled automatic stacking program (supporting modes like “herringbone” and “circular”), it avoids dead zones in coal stacking, increasing the 54-meter stockpiling area’s inventory capacity to 85,000 tons, a 28% improvement over traditional fixed stackers.
In terms of hardware, the ZR120SF is equipped with a 1200 mm wide Conveyor Belt (suited for coal particle sizes of 0.5–10 mm), with a belt speed of 3.15 m/s and a maximum theoretical handling capacity of 1500 m³/h (approximately 1275 tons per hour at a coal bulk density of 0.85 t/m³). In actual operation, variable frequency control stabilizes the capacity at 460 tons per hour, meeting current demands while providing room for future capacity upgrades. The power system uses an efficient drive unit paired with a hard-tooth-surface reducer (transmission efficiency ≥96%), ensuring long-term stable operation.
Sealed and Environmentally Friendly Design
The stacker’s discharge end is equipped with a non-powered dust suppression chute with an internal airflow buffer chamber, reducing airflow speed during coal discharge to minimize dust generation. The conveyor belt adopts an overlapping sealed structure (overlap ≥120 mm) with rubber sealing skirts at the discharge end, completely blocking dust escape routes. A UV-resistant transparent dust cover on the stacker’s cantilever section facilitates open-pit inspections while reducing wind-driven dust dispersion, ultimately controlling system dust emissions to within 8 mg/m³. The sealed conveying and stacking structure also isolates rainwater, reducing the coal caking rate during the rainy season to 0.8%, eliminating additional crushing costs.
Open-Pit Durability
The chassis adopts a lattice frame design made of high-grade carbon steel, with a 30% improved strength-to-weight ratio, supporting heavy loads and 12° slope operations. The travel system uses eight solid tires with a ground pressure of ≤0.08 MPa, preventing equipment from getting stuck in soft open-pit terrain. The hydraulic power unit, equipped with a 500L oil tank and an integrated oil temperature control system, operates reliably in temperatures from -5°C to 40°C, reducing hydraulic component failure rates by 40%.
Supporting Equipment
To ensure seamless integration from truck unloading to stacker operation, the solution includes two types of ZOOMRY-developed equipment:
- Wheel-Type Truck Unloader: As the coal receiving equipment, it features a 1400 mm belt width and a handling capacity of 200–1000 tons per hour, suitable for 30-ton dump trucks commonly used at the factory. It includes two 6.7° hydraulically adjustable ramps (allowing trucks to unload without reversing), with rubber sealing skirts at the ramp base to reduce dust emissions. A vibrating feeding device adjusts the discharge rate based on the stacker’s status, preventing coal accumulation at the unloading area.
- hopper feeder: Positioned between the truck unloader and stacker, it has a 5 m³ hopper capacity and an 18.5 kW variable-frequency motor for real-time feeding adjustments, ensuring a stable 450-ton-per-hour coal flow to the stacker. The hopper’s inner walls are lined with 12 mm wear-resistant ceramic plates to combat abrasion, and a color-coated steel rainproof canopy prevents rainwater-induced coal caking.
Core Components
All critical components are independently manufactured by ZOOMRY, with performance surpassing national standards:
- Rollers and Pulleys: The stacker and truck unloader use silent rollers (133 mm diameter, suited for 1200 mm belt width), with radial runout ≤0.4 mm (better than the national standard of 0.5 mm) and water ingress ≤95 g after a 72-hour immersion test. Pulleys are made of 40Cr forged material (159 mm diameter) with diamond-patterned rubber coating (friction coefficient ≥0.4) to prevent coal slippage, with ovality <1.5 mm, subjected to ultrasonic testing and stress-relief tempering, offering a service life exceeding 50,000 hours.
- Cleaning and Safety Components: The stacker is equipped with two PU cleaning scrapers (one at the head, one at the tail) with ≥95% belt contact, removing residual coal dust to prevent belt misalignment. It features “dual safety protection”—a belt misalignment switch (alarms at >5 mm deviation) and a hydraulic winch self-locking system (locks within 0.01 seconds after power failure, preventing telescopic arm collapse), ensuring safety in unattended open-pit conditions.
Project Implementation Process
Preliminary Survey and Design
ZOOMRY dispatched a five-person technical team to the factory, completing within 10 days: 3D terrain mapping of the 54-meter stockpiling area using a total station, marking the 12° slope and drainage points to optimize the stacker’s track layout and avoid water accumulation during the rainy season; laboratory testing of coal samples for flowability, abrasiveness, and moisture content to determine stacker parameters; and development of an open-pit protection plan based on local weather data, including dust cover layout and hydraulic oil temperature control settings.
Manufacturing
All equipment and components were produced at ZOOMRY’s Hebei factory, integrated into ISO 9001 and ISO 14001 systems. The radial telescopic stacker’s chassis frame passed a 24-hour static load test at 1.2 times the rated load without deformation. Rollers underwent a 1000-hour no-load test to verify sealing and rotational resistance (≤2 N, better than the national standard of 3 N). The truck unloader’s hydraulic system completed a 72-hour cycle test to ensure no leaks. Factory acceptance confirmed all parameters met contract requirements, with outstanding results in open-pit durability tests (high/low temperature cycles, rain exposure).
Installation and Commissioning
An eight-person installation team adopted a “modular assembly + rainproof construction” approach. The radial telescopic stacker’s main body was divided into five segments (10–12 meters each), pre-assembled at the factory, requiring only bolt connections and hydraulic pipeline docking on-site, completed in 18 days (industry average: 30 days). Temporary rainproof canopies protected components during rainy days to prevent corrosion. A 72-hour full-load test simulated open-pit conditions, optimizing the stacker’s PLC program to achieve a stable 460-ton-per-hour stacking efficiency. The truck unloader and feeder’s integration logic was synchronized to ensure precise matching of feeding and stacking capacities.
Maintenance Training
ZOOMRY provided 15 days of specialized training for two factory maintenance personnel, covering daily inspections, troubleshooting, and regular maintenance, with additional open-pit skills like “rainy season drainage checks” and “winter hydraulic preheating.” The training ensured the team could independently operate and maintain the equipment. ZOOMRY’s spare parts warehouse guarantees delivery within 7 days, with a 24-hour multilingual hotline for lifelong technical support.
Project Outcomes
After commissioning, the system achieved stable long-term operation, delivering significant value to the Guizhou open-pit factory:
- Efficiency and Capacity: The ZR120SF radial telescopic stacker achieved a stable 460 tons per hour, increasing the 54-meter stockpiling area’s inventory capacity to 85,000 tons, eliminating temporary transfers. The unloading-to-stacking cycle was reduced from 4 hours to 1.8 hours, cutting annual downtime by approximately 35 hours, indirectly boosting production. The integrated truck unloader, feeder, and stacker ensured precise matching, eliminating accumulation or idling.
- Environmental and Material Utilization: The sealed system reduced dust emissions from 22 mg/m³ to 8 mg/m³, avoiding complaints and penalties. Coal loss rate dropped from 5% to 0.8%, saving approximately 35,000 tons annually at a daily stockpile of 12,000 tons. The rainy season caking rate fell to 0.8%, eliminating additional crushing costs.
- Reliability and Durability: Core components maintained stable operation, requiring only periodic belt and scraper replacements, reducing annual maintenance frequency from 12 to 4 times and costs by 40%. In -5°C to 40°C conditions, the annual failure rate was 0.6% (below the industry’s 1%). A secondary capacity upgrade to 500 tons per hour required only minor PLC and motor adjustments, showcasing scalability.
The factory project manager stated: “ZOOMRY’s stockpiling system resolved our efficiency and environmental challenges, operating reliably in open-pit conditions with seamless integration and easy maintenance. We will prioritize ZOOMRY’s solutions for future expansions.”
ZOOMRY’s Core Competitive Advantages
- Comprehensive Product Line: ZOOMRY offers a full chain of “truck unloader + hopper feeder + radial telescopic stacker,” with precisely matched parameters, avoiding compatibility issues and ensuring seamless stockpiling.
- Tailored Adaptability: ZOOMRY’s R&D team optimizes designs for open-pit conditions like slopes, temperature variations, and rainwater, reducing adaptation time by 50% compared to international brands.
- Global Service Support: Equipment complies with ISO 9001, ISO 14001, CE, and EAC certifications. Global spare parts warehouses and multilingual support address overseas clients’ challenges, with response times exceeding industry averages.
