Development and Evaluation of Corrosion Resistant Coating for Expandable Rock Bolt against Highly-Corrosive Ground Conditions

Ma, Kevin J. ; Stankus, John ; Faulkner, Dakota
Organization: International Conference on Ground Control in Mining
Pages: 8
Publication Date: Jan 1, 2017
"Expandable rock bolts are widely used in hard rock mines as an efficient ground control product. However, capacity and service life can be significantly reduced if the metallic body is subjected to corrosion. In some hard rock mines in the U.S., highly corrosive ground conditions exist, and it has been reported that inflatable rock bolts have corroded within a few months after installation. To provide mining industry a cost-effective inflatable bolt and combat the corrosion issues, Jennmar Corporation, Inc., and its subsidiary Keystone Mining Services, LLC (KMS), analyzed corroded bolt samples, identified root causes, evaluated properties of various coating materials, and developed a new inflatable rock bolt, Python M3TM, that is protected with an innovative PyFlexU2TM coating. The new generation Python M3 features improved steel chemistry for reliable performance, modified profile for better inflation, and surface preparation and coating application. The PyFlexU2 is impervious to liquid and air, durable, and UV resistant. With a flexible adhesive, and highly corrosion-resistant undercoating, and a very hard sacrificial surface coating, the PyFlexU2 coating system provides the Python M3 superior protection against chemical corrosion and physical scratch damage. The under-coating has exceptional flexibility and adhesion to prevent coating micro-cracks or fractures after bolt inflation and possesses excellent corrosion resistance to acids (pH <3), alkalis (pH >11), fuels, and salt solvents. The corrosion and scratch resistant PyFlexU2 coating offers very effective bolt protection for extra longevity in highly corrosive environments. The Python M3 coated with PyFlexU2 has been tested in the most challenging conditions, including laboratory corrosion tests in extreme acidic and basic solvents, rock slurry, and borehole scratch insertion tests. With demonstrated corrosion and scratch resistance, the product has been greatly welcomed by hard rock mines in the West and is currently installed in large scale. This paper identifies the root causes of the bolt corrosion, discusses the analysis process, and details laboratory and underground tests carried out on the Python M3 coated with PyFlexU2. The Python M3TM and PyFlexU2TM are subjects covered by pending U.S. Patent Applications assigned to FCI Holdings Delaware, LLC."
Full Article Download:
(2338 kb)


Additional chapters/articles from the SME-ICGCM book Proceedings of the 36th International Conference on Ground Control in Mining

Analysis of Monitored Ground Support and Rock Mass Response
Applying Robust Design to Study the Effects of Stratigraphic
Evaluation of Seismic Potential in a Longwall Mine with Mass
Damage and Permeability Evolution Mechanisms of Coal under U
Coal Bursts That Occur During Development: A Rock Mechanics
Geotechnical Challenges and Experiences of Working a Deep an
Case Study of the Barro Branco Coal Mine Pillar Burst
Numerical Modeling the Interburden Impact on Multiple-Seam C
Basic Procedures for Monitoring and Modeling Abandoned Under
Coal Rib Response during Bench Mining: A Case Study
Geotechnical Considerations for Concurrent Pillar Recovery i
Highwall Mining of Thick, Steeply Dipping Coal: A Case Study
Coal Pillar Design When Considered as an Overburden Reinforc
Analysis of Global and Local Stress Changes in a Longwall Ga
CBM Extraction Engineering Challenges and the Technology of
Numerical Analysis of the Effect of Coal Seam Characteristic
3D Modelling of Mine Backfill
Spreading of Ground Pressure Fluctuation in the Gob
Research Progress on Fully Mechanized Mining Technology of S
Fundamental Principles of an Effective Reinforcing Roof Bolt
Ten Factors about Standing Supports That Might Surprise You
Effect of Vertical Discontinuities on Roof Stability and Gro
The Relationship between Ultrasonic Velocities and Mechanica
Moisture–Induced Swelling of Illinois Mine Roof Shales: A Vi
Ground Control of Longwall Top–Coal Caving Faces within Thic
Coal Strength Variation by Lithotype for High-Volatile a Bit
Deep Cover Bleeder Entry Performance and Support Loading: A
Study on Appropriate Support System and Control Criteria for
Case Study and Design of Standing Steel Set Support for Aged
Modeling the Effect of Bolts on the Behavior of Rock Pillars
Tekcrete Fast®: Fiber-Reinforced, Rapid-Setting Sprayed Conc
A New Generation of Web-Based Applications for Mine Design
User-Friendly Finite Element Design of Main Entries, Barrier
Development and Evaluation of Corrosion Resistant Coating fo
Mechanism and Prevention Measure of Rib Spalling in 6.5 Mete
Development Process for a Greater Capacity Propsetter® Syste
Development, Trials, and Testing of a Two-Component, Rapid-S
Application of Updated Joint Detection Algorithm for the Ana
Study of the Backfill Confined Consolidation Law and Creep C
Changes in Stress and Displacement Caused by Longwall Panel
Geotechnical Monitoring of Rock Mass and Support Behaviour a
Upwards Surface Movement above Deep Coal Mines after Closure
The Use of the Area of Main Influence to Fix a Relevant Boun
High-Precision Dynamic Subsidence Prediction Model Aided by
SDPS Update: Easy Calculation of the Edge Effect Offset for