Australasian Mining Review

application in which they are installed. They can fail by internal effects such as manufacturing defects, poorly designed hose/coupling interface, continuous pressure impulse spikes above working pressure, temperature spikes and by external effects such as poor crimping, twisting, external cover abrasion, cuts, or gouges. The program tracks hose assemblies from cradle to grave thereby identifying when the hose fails and what was the failure mode. 3. What are the events that cause each failure? Many events cause these failures but most are related to manufacturing processes, crimping practices, installation practices and engineering practice. Analysis of each failure will help to recommend the right product that will ensure from the beginning the highest possible reliability for a particular hose assembly. 4. What happens when each failure occurs? Usually, when a hose assembly fails on a piece of mining equipment the equipment is out of service immediately after the failure. Although the frequency will vary, from a mining operator's perspective the severity is high and immediate. Additional risks that are involved are severe injury to the operator and potential complete loss of the piece of equipment due to a fire for example. In addition, the environmental consequences of a failure might be severe depending on which hose assembly fails. Usually, the cost of the hose assembly that fails pales in comparison with all the other costs that are involved with a failure. 5. In what way does each failure matter? Each failure matters because it will affect to a greater or lesser extent the profitability pyramid of a mining operations described in Figure 3: Every one of the sub-pyramids can have an economic value associated with them and in conjunction changes in them will lead to incremental positive or negative cash flows in a given mining operation. 6. What systematic task can be performed proactively to prevent, or to diminish to a satisfactory degree, the consequences of the failure? The most proactive action an operator can take to prevent or diminish to a satisfactory degree the consequences of failure is to take an Applications Engineering approach. This approach involves studying the hydraulic system on the machine and prescribing the right hose assembly component for that application. In addition, Application Engineering helps with the serviceability of the machine when it comes the time for Hose Assembly fabrication, replacement while also helping with the cost of the machine's Bill of Materials 7. What must be done if a suitable preventive task cannot be found? Time and answers to questions 1 through 6 will help build a database of well documented cases that will help the user to establish maintenance principles and a body of maintenance tasks (preventative and/ or predictive) where correct remediation is not immediately obvious. So, this body of information is the essence of the Hose Management Program. KEY COMPONENTS OF THE HOSE MANAGEMENT PROGRAM • Key performance Indicators to be determined at the beginning of the implementation of the program • High performance products that will enable a significant reduction in undesired outcomes • Product application engineering analysis that will optimize hydraulic systems • Hose assembly tagging and tracking to track the lifecycle of every hose assembly • Internal Condition Monitoring and engineering analysis of selected hydraulic circuits • External Condition Monitoring of hose assembly conditions • Risk analysis based on hose assembly function and location on a given piece of equipment • Reliability Based Replacement Alerts based on condition monitoring APPLICATIONS OF THE HOSE MANAGEMENT PROGRAM By applying some or all of the components of the Reliability Based Hose Management program as described above it has been possible to produce the following results at several different types of mining operations described in Figure 4. RELATION BETWEEN THE COST OF A HOSE ASSEMBLY & THE COST OF DOWNTIME An idea of the relationship between the cost of downtime for selected mining operations and the cost of a hose assembly on a given machine are presented in two examples shown in Figure 5. CONCLUSION The paper discusses Reliability Based Maintenance applied to Hose Assemblies and shows the results produced by applying one or more components of a Reliability Based Hose Management Program in several mining operations around the world departing from a time based maintenance program to a condition based maintenance program. This new approach in hose assembly maintenance has shown significant improvement in Mean Time Between Failures, Reduction in the Total Cost of Ownership and improvement in Mobile equipment Fleet availability. The main factors determining the success of mining operations were discussed and it is shown that the acquisition cost of a hose assembly is insignificant compared to the value of downtime of a major piece of equipment in any mining operation. Paulo is a mining engineer with 32 years experience in operations, sales and business development, with a target to increase mining productivity. Paulo graduated with a Master of Science from the Colorado School of Mines and a Bachelor Degree from the Catholic University in Brazil. SURFACE GOLD MINE HEAP LEACH • Cost of Hose Assembly: up to $840.00 • Content per Machine: up to $25,000 • Lost production per hour of downtime on a prime mover: $77,000/Hr • Spot Gold Price at 1,300/oz SURFACE COAL MINE • Cost of Hose Assembly: up to $1,100.00 • Content per Machine: up to $40,000 • Lost production per hour of downtime on a prime mover: $27,000/Hr • Spot Price of Coal at $7.53/metric ton F I G U R E 5 RELATIVE VALUES OF DOWNTIME, CONTENT PER MACHINE & HOSE ASSEMBLY PRICING A U T H O R P R O F I L E PAU LO P E R E I R A 87 www.miningreview.com.au / ISSUE 12 / AUST R A L AS I A N M I N I N G R E V I E W

• Cover