2026-10-31
Located in the arid Kyzylkum Desert region of Zarafshan, Navoiy Region, Uzbekistan, a major open-pit gold mining and hydrometallurgical processing plant operates a continuous carbon-in-leach (CIL) circuit with a total process water circulation capacity of 3,200 m³/h. The process water loop recycles barren cyanide solution and decant water from tailing storage facilities (TSF). The circulating fluid is heavily laden with ultra-fine silica dust, residual iron cyanides, calcium sulfate scale precursors, and abrasive gold-bearing ore micro-slurry.
The mining complex operates in an extreme climate where summer temperatures exceed 45°C, making raw river water abstraction from the Amu Darya river strictly regulated under Uzbekistan's national environmental quotas. The facility originally relied on bank-mounted duplex bag filtration assemblies to protect downstream heat exchangers, high-pressure elution column pumps, and electrowinning cell spray nozzles. However, the abrasive micro-slurry caused severe operational bottlenecks, leading the mine operator to seek an automated, continuous filtration upgrade from LEFILTER to stabilize gold recovery rates and maintain environmental compliance.
Excessive Downtime and Production Line Stoppages: The incoming liquid carried fine quartz particles ($D_{50} = 45\,\mu\text{m}$) and sticky clay colloids. The existing manual bag filters blinded completely every 24 to 36 hours. Replacing bags required shutting down fluid delivery to the elution circuit for 5 to 7 hours per event, restricting overall gold bullion output by over 8%.
High Operating Expenses for Disposable Media: The plant consumed over 1,400 high-capacity synthetic filter bags monthly. Due to local cyanide contamination protocols, spent bags were classified as hazardous chemical waste, resulting in extreme toxic waste disposal and incineration fees alongside escalating supply chain shipping costs to central Asia.
Severe Mechanical Wear and Thermal Stress: Unfiltered slurry bypass caused rapid erosion of titanium plate heat exchangers and high-pressure elution pumps. Abrasive scoring on pump impellers led to unexpected mechanical failures and localized fluid leaks, posing severe worker safety risks due to trace residual cyanide.
Stricter Environmental Penalties for Water Abstraction: Frequent filter bag flushing and manual filter cleanouts consumed massive volumes of clean raw water. The site regularly exceeded its seasonal groundwater withdrawal quota, incurring escalating financial penalties from the Uzbek State Committee for Ecology and Environmental Protection.
LEFILTER’s international metallurgical engineering team developed a complete, automated filtration skid featuring four parallel LEFILTER LF-FC Series Multi-Chamber Automatic Backwash Filters engineered specifically for aggressive chemical environments.
Corrosion-Resistant Structural Build: The filter housings were manufactured from ASME-certified 316L stainless steel, internally polished and passivated to withstand continuous exposure to mild alkaline cyanide solutions ($pH\ 10.5\text{--}11.5$) and elevated chloride contents.
Precision Wedge Wire Element Design: Instead of woven mesh or fabric, LEFILTER integrated V-shaped 316L wedge wire filter elements with a 150 $\mu\text{m}$ rating. The smooth slot surface prevents particle entrapment, while the inverted V-profile allows rapid release of fine solids during reverse flow.
Non-Stop Multi-Chamber Backwashing: Each vessel contains eight independent filtration chambers. When the differential pressure reaches 0.12 MPa, an internal rotating mechanism isolates one chamber at a time for reverse flow purging using the clean system fluid, while the remaining seven chambers continue uninterrupted 100% duty-cycle filtration.
Localized Control and Remote Integration: The system includes an IP65-rated control cabinet with a Siemens S7-1200 PLC and a bilingual (Russian/English) touchscreen interface. It communicates seamlessly via Modbus RTU with the mine’s main ABB Distributed Control System (DCS), allowing operators in the central control room to monitor real-time pressure drops, backwash frequency, and valve positions.
Turnkey Logistics and Field Commissioning: The entire skid was pre-assembled, pressure-tested to 2.4 MPa, and shipped via direct multimodal rail transport to Zarafshan. LEFILTER deployed two senior field service engineers on-site for 14 days to oversee mechanical positioning, piping tie-ins, and DCS calibration.
Following 18 months of continuous operational monitoring at the Zarafshan gold plant, the LEFILTER LF-FC multi-chamber backwash system achieved exceptional technical and financial performance metrics:
Suspended Solids Interception Rate: Maintained a consistent 93.4% removal rate of suspended solids larger than 150 $\mu\text{m}$, reducing process stream turbidity from over 420 NTU to under 28 NTU.
Uninterrupted Operations & Capacity Enhancement: Completely eliminated planned and unplanned filtration-related plant shutdowns, recovering an estimated 420 hours of production time annually. This increased annual gold ore processing throughput, delivering a calculated net value gain of USD $1.15 million.
Zero Disposable Filter Consumables: Disposable filter bag consumption dropped to zero, eliminating over USD $145,000 in annual media procurement and hazardous chemical waste handling costs.
Water Conservation & Penalty Avoidance: Total backwash wastewater volume dropped by 68% compared to manual bag flushing. The plant reduced raw water intake by 112,000 m³ annually, completely avoiding municipal over-abstraction fines.
Extended Equipment Lifecycle: The operating lifespan of downstream plate heat exchanger gaskets and elution pump seals expanded from 3 months to over 14 months, cutting maintenance labor costs by 62%.
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