I. Process Background
With the advancement of “zero-waste mine” and green-mine initiatives, full‑tailings cemented filling technology has been widely adopted in large non‑ferrous and ferrous metal mines across China. This process uses mill tailings as aggregate, mixes them with cement, additives, and water, and homogenizes them into a paste slurry (typical concentration 65%–78%) using a high‑consistency vertical mixer. The slurry is then pumped via plunger pumps through boreholes and pipelines to underground voids, achieving both harmless disposal of tailings and support for the mined-out areas. Density (concentration) control of the paste slurry is the linchpin of the filling station: if the concentration is too low, the slurry tends to segregate and leach water, resulting in insufficient strength after setting and an increased risk of collapse; if it is too high, pipeline resistance rises sharply, leading to frequent blockages and even pipe ruptures, causing production shutdowns and equipment damage.
Meanwhile, in the grinding circuit (ball mill–hydrocyclone–return to ball mill), the feed density to the hydrocyclone directly determines the classification particle size and the mill’s recirculating load, making it a key control parameter for grinding energy consumption and metal recovery. Excessively high feed density causes “overgrinding,” wasting energy and leading to metal losses; too low a density results in “coarse material passing through,” with oversized particles entering the flotation stage and lowering recovery rates.
II. Pain Points of Traditional Density‑Measurement Solutions
• The filling‑paste slurry has a high concentration (water content only 22%–35%), coarse and hard particles, and poor flowability; differential‑pressure transmitters’ diaphragms are easily worn through, and tuning‑fork meters frequently suffer from tine wear and fracture.
• Although gamma‑ray density meters can handle high‑concentration slurries, underground mine workings and filling stations are densely populated areas with frequent equipment maintenance, placing significant pressure on radiation safety management.
• The feed density to the grinding hydrocyclone fluctuates dramatically (affected by feed particle size, slurry temperature, hydrocyclone fouling, etc.); conventional instruments respond slowly with substantial lag, failing to provide timely feedback to the DCS for adjustment.
• Modern mines are pursuingsmart automation and unattended operation, demanding instruments that are maintenance‑free, long‑lived, and capable of remotely uploading data to the cloud—requirements that traditional devices struggle to meet.
III. PS7000 Solution
The PS7000 is tailored for two typical mining applications: the discharge line of the plunger pump at the filling station and the feed line to the grinding circuit’s hydrocyclone. It features a flanged direct‑insertion installation, covering DN50 to DN1000 and accommodating the diverse pipe sizes found in mines. An ExdⅡCT6Gb explosion‑proof version is available, meeting the requirements for underground operations.
Figure 5 Schematic of density measurement in mine tailings filling and grinding circuit processes
Core Value of the PS7000 in the Mining Industry ▸ Non-contact measurement—completely eliminates wear and clogging of instruments caused by highly concentrated paste slurries; ▸ The Chirp algorithm delivers a measurement response time of less than 1 second, enabling the DCS to instantly detect and regulate fluctuations in grinding circuit density; ▸ The ceramic probe withstands continuous abrasion from paste slurries with concentrations of 65% to 78%, with a service life of at least 5 years; ▸ Non-nuclear—zero radiation—ensuring intrinsic safety in underground operations and backfill stations; ▸ Optional 4G cloud-connectivity module supports mine-level intelligent centralized monitoring and unattended operation. |
IV. Customer Value
Comparison Dimensions | Original Conventional Solution | PS7000 Solution |
Instrument service life | Diaphragm/tuning fork frequently worn | Ceramic probe ≥ 5 years |
Tube burst / blockage incidents | Density out of control → Major safety risk | Precision density control → Significant risk reduction |
Grinding Response Speed | Lag → Coarse discharge / Overgrinding | < 1 second → real-time DCS control |
Metal recovery rate | Fluctuations in particle size lead to a decline in recovery rate | Stable particle size · Improved recovery rate |
Intelligent Adaptation | Local instruments — Difficult to migrate to the cloud | 4G module · Mine-grade remote monitoring |
At a full‑tailings filling station in a gold mine in Shandong, the PS7000 replaced the original differential‑pressure density meter on the filling pipeline. After one year of operation, slurry concentration fluctuations narrowed from ±2.5% to ±0.6%, eliminating the previous issues of pipeline blockages and ruptures. Simultaneously, PS7000 was deployed on the feed line to the grinding circuit’s hydrocyclone, working in conjunction with the DCS to implement closed‑loop control of the water addition. Mill energy consumption decreased by approximately 4%, and metal recovery improved by 0.6 percentage points, yielding significant annual economic benefits.
