Magnetic Level Indicator Float Level Switch with Alarm

Underground Block Cave Mining Drawpoint Level Monitoring System

Block caving is an underground mining method used to extract massive, low grade ore bodies such as copper porphyries and diamond bearing kimberlite pipes. During block caving, a large block of ore is undercut and allowed to collapse under its own weight, breaking into fragments that flow by gravity into drawpoints and then into haulage drifts. Managing the drawpoint material level is critical: too low and waste rock falls in, diluting the ore; too high and fragmented ore can bridge, blocking flow and creating dangerous air gaps. Traditional manual level checks are infrequent, subjective, and place workers in hazardous locations. The BlockCave Drawpoint Sentinel provides continuous remote level monitoring of each active drawpoint using laser or radar rangefinders, integrating with automated load haul dump (LHD) dispatch to optimize draw control and reduce dilution by up to 50%.

Underground Mining Technology for Ore Recovery Optimization:

• Laser and Radar Rangefinding Through Dust and Water Sprays: Drawpoints are subject to dust, water spray from dust suppression, and fragmented ore surfaces. The system uses frequency modulated continuous wave radar that penetrates dust and operates reliably in dark, wet conditions. The sensor is mounted on the drawpoint brow and measures the distance to the broken pile surface with 10 millimeter accuracy. A laser pointer aids alignment during installation.

• Drawpoint Condition Alerts for Bridging or Overdraw: The platform continuously tracks each drawpoint's pile height and rate of descent during LHD extraction. If the rate of descent stops while the LHD is mucking (indicating a bridge), the system alerts the operator to use a scaling bar or remote hammer. If the pile falls below the minimum allowable height (typically 1.5 meters), it blocks further extraction until a supervisor reviews the risk of dilution.

• LHD Integration for Automated Draw Control: The system communicates with the wireless LHD dispatch system. When an LHD approaches a designated drawpoint, the operator sees the current pile level on their onboard display. The system can automatically assign drawpoints to LHDs based on which ones have the highest priority (i.e., nearest to the optimal draw range), maximizing production while avoiding dilution.

• Historical Draw Performance Analysis for Mine Planning: All drawpoint level data, extraction rates, and tonnage drawn are logged to a central database. Mine engineers analyze drawpoint performance to identify areas of poor flow, refine cave propagation models, and plan future undercut sequences. The system generates weekly draw control reports that compare actual extraction against the planned production schedule.

Block Cave Draw Control Workflow for Maximum Recovery:

1. Drawpoint Calibration and Safe Zone Definition: For each drawpoint, engineers define the optimal operating range between a minimum level (avoid waste dilution) and maximum level (avoid bridging). These values are entered into the system.

2. Real Time Drawpoint Monitoring and LHD Guidance: During production shifts, the system displays color coded drawpoint statuses (green = ready, yellow = approach caution, red = do not draw) on operator consoles. LHD drivers follow the guidance, drawing only from green points.

3. Event Detection and Response to Bridging: When the system detects a drawpoint bridging event (level not dropping while LHD is extracting), it sends an alarm to the shift supervisor and logs the event. The supervisor can direct borehole camera inspection or remote hammer application to break the bridge.