Draslovka Mining operates the world’s largest solid sodium cyanide production facility, supplying the mining industry with reagents essential for precious-metal extraction. At their Memphis plant, sodium cyanide is produced using legacy compression equipment—including a Delaval 3c30/24 centrifugal blower originally commissioned in 1964. The unit forms part of Compressor Train #1, which was last serviced in 2019 by Siemens.

The client engaged Blackstone to perform a Minor Inspection on the steam turbine and compressor after reporting performance degradation and having all required spares on site.

The Memphis facility operates three compression trains critical to sodium cyanide production. Unit #1—powered by a 1964 Delaval centrifugal compressor—remains the primary operating train. Unit #2 has reached the end of its service life, and Unit #3 is currently undergoing a multimillion-dollar revamp by Siemens Energy for future commissioning.

Given the age of Train #1, the client requested a focused Minor Inspection to verify mechanical integrity, validate alignment and clearances, and keep production running until the Unit #3 upgrade is complete.

Planned Scope

• As-found alignment between compressor and steam turbine

• Measurement of axial and radial clearances across bearings and seals

• Inspection of turbine and compressor bearings

• Re-assembly and pedestal sealing with as-left measurements

Client-Requested Additions (Onsite)

• Removal of 8″ steam piping spool for turbine inspection

• Borescope inspection of steam control valves, turbine inlet, and last-stage blades

• Visual inspection of the Gimple valve

• Manual surface smoothing of journal bearing pads and shaft journals due to lack of spares

• Cleaning of significant contamination inside all bearing pedestals

• Inspection and preservation of bearing pedestal components for Train #3

• Removal and borescope inspection of compressor balance line

• Removal and machining of thrust collar to correct deep scratches

• Fabrication of special tool for thrust-collar removal (via client’s 3rd-party machine shop)

• Calculation and machining of new shims for turbine and compressor axial clearances

Abnormal wear in Compressor thrust and journal bearings.

• No available replacement bearings or pads for compressor DE and NDE
• Scope continuously increased by client during execution
• Evidence of abnormal oil contamination in bearing housings
• Deposits and wear found in probe pickup areas
• Severe wear on thrust collar, thrust faces, and shaft journals

Abnormal wear and deep scratches in thrust collar and shaft journals.

• Completed in 7 shifts despite added scope—no production downtime
• Compressor restored to reliable operation with no new spares available
• Train #1 performance improved from 30% of nominal efficiency to 100% nominal speed
• Bearing contamination removed, extending operating life (replacement still recommended)
• Source of water ingestion identified for corrective action
• Train stabilized at low vibration levels
• With Unit #2 at end of life, Blackstone can propose a modern, energy-efficient replacement compressor
• Elevated temperature in the steam turbine DE bearing (rebabbitted by a 3rd party) presents an opportunity for Blackstone rebabbitting and engineered spare-part services