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MillSlicer PMC Phalaborwa AG Mill Initial Installation Trends and Results

The following items obtained from the first couple days of system installation are presented in the next several slides:

I. PMC Single Page (double sided) Operator’s Guide for understanding the new MillSlicer signals. A. Polar Plots are shown that illustrate the toe movement between an empty and full mill. B. The toe 4-20mA signal along with the new inlet, shell and outlet fill level signals.C. A basic control strategy using the toe signal and how to increase/decrease the auto-control set point.

II. Initial PMC Trend Data running under manual control the first day of MillSlicer operation. A. Toe, Inlet, Outlet and Shell Fill level signals along with the usual process control variables.B. Brief Observations.

III. Initial Trends running under auto-control (using the toe 4-20mA signal) the second day of MillSlicer operation.A. Toe, Inlet, Outlet and Shell Fill level signals along with the usual process control variables.B. Brief Observations and Summary.

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Operator’s Guide - MillSlicer Polar Plot Toe Position (PMC AG Mill #1 Data)

Real-time ToeAngle

Under-filled Mill

Toe = 152o

Full Mill

Toe = 136o

Note: As the mill fills, the load shifts up on the liner. Toe Angle 0 degrees = 4 mA, Toe 360 degrees = 20 mA

Mill Rotation

Mill Rotation

Bearing Pressure

Mill Power

Water

Outlet Fill Level (green)

Inlet Fill Level (blue)

Shell Fill Level (teal)

Feed (red)

Toe = 152o

Toe = 136o

0o

90o

180o

0o

90o

180o

Page 1 of 2

PMC Operator’s Guide MillSlicer Toe Position Auto Control Strategy

Bearing Pressure

Mill Power (black)

Water (light blue)

Feed (red)

Fill Level Signals:Shell

(teal) Inlet (dark

blue)Outlet

(green)

Toe = 152o

Toe = 144o

Basic Automatic Control Strategy:1. Empty mill start-up set-point for Toe Angle = 145o. Enter this set point and start auto-feed control. 2. As the mill fills, observe how bearing pressure & power increase over time (see trends).3A. If power or bearing pressure begin to reach their maximum limits, increase the toe set point. i.e. change toe angle set point from 145o to 147o. This should now reduce the feed and empty the mill.3B. If power or bearing pressure are significantly below their maximum limits, decrease the toe set point. i.e. change toe angle set point from 145o to 143o. This should now increase the feed and fill the mill.

Note: Upon start-up, it is recommended that the operator run the mill in manual control to more quickly bring the mill up to the desired power/pressure operating point and then switch to auto-control. Page 2 of 2

Initial MillSlicer Toe and Typical Process Signals – 1st Day

Bearing Pressure

Mill Power (black)

Water (light blue)

Feed (red)

Fill Level Signals: Shell (teal) Inlet (dark blue)

Outlet (green)

Manual Control Only (3 hour Trend Duration)

Toe

1. Drops in feed are due to metal detected on the feeder. Metal must be cleared before feeders re-start.2. Shell vibration signal (Teal) does not show much variation over the 3 hour interval.3. Inlet (dark blue) and Outlet (green) vibration signals vary with mill load but remain constrained

between 55-80%. The Outlet has the greatest dynamic range and should be able to detect a blockage very quickly. Unfortunately the operator confidence is quite low (and problems with metal in the feed) mean that the mill is typically being run in an under-loaded condition.

4. Toe shows the greatest variation of all the new MillSlicer signals.

Bearing Pressure

Mill Power (black)

Water (light blue)

Fill Level Signals: Shell (teal, top)

Inlet (dark blue)

Outlet (green)

Feed (red)

Toe (orange)

Initial MillSlicer Toe and Typical Process Signals – 2nd Day Morning

Auto Control (2 hour Trend Duration)

1. Toe, Power & Pressure all show the mill filling while shell and inlet show the mill emptying slowly.2. Outlet remains relatively constant (no problems). All three vibration signals run in parallel.3. Toe set-point for auto control is 146 degrees which we briefly attained so feed was cut and then

increased as the Toe increased back up. Note: The actual feed delivered versus the auto control desired amount was found to be many times 5-10% off. i.e. Desired 700 TPH, Actual 630 TPH (10% off)

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Initial MillSlicer Toe and Typical Process Signals – 2nd Day Afternoon

Auto Control (2 hour Trend Duration)

Bearing Pressure

Mill Power (black)

Water (light blue)

Fill Level Signals: Shell (teal, top)

Inlet (dark blue)

Outlet (green)

Feed (red)

Toe (orange)

1. More trouble with the feeders initially. Auto Control is asking for a conservative 850 TPH and actual is over 1000 TPH for the clipped periods of time.

2. Toe set point for auto control is kept at 146 degrees. We go below this point after ~30 minutes and so the feed is gradually decreased. Mill Power & Bearing Pressure are kept away from their max limits and so the control room is impressed.

3. First night of the night shift operator using the new signals, record production is recorded for the shift.4. 8-9% improvement in overall production since installation is reported by Ensight mining consultants

given the task to optimize power consumption and production via new automation technologies.