If a truck breaks down for more than 2 hours near the beginning of the shift, then the driver has spare time, so the model assumes the driver does not need to stop again for coffee. For example, at the Lucy mine the average tire life is about 5, operating hours. This check is made at the dump or crusher location. As a truck moves, heat is generated from contact with the road surface and from flexing of the tire sidewalls. Tire temperature affects normal wear in a very negative way, typically on an exponential basis. The results shows that tire surface temperature rises exponentially during travelling and achieves a steady state temperature at the end of eight miles of travelling.

For ambient temperature, the model has an option to assume a constant value or uses a look up table according to Lucy mine temperature Appendix This feature allows a mine engineer to set different crew makeup to see the impact on KPIs. An economic assessment of an AHS system versus a manual fleet shows an after-tax incremental discounted cash flow rate of return of Tire wear impact factors mine haulage compared to regular asphalt????..??? For each model step time, acceleration is assumed to be constant, and using fundamental physics, the speed, distance, engine speed, BSFC break specific fuel consumption are determined at the end of the time interval. Critical evaluation essay outline example.

Figure 28 shows driver speed variations while Figure 29 shows the instantaneous net power for this segment.

Sleep deprivation studies show that as driving hours increase, a significant increase in the range of lateral position in a highway lane occurs Kozak et al, pparreira, while Vester et al identified that shorter segments show lower percentage SDLP values. This gives an overall average of pxrreira Figure 20 shows the first segment of the route Parking to Waste Shovel. With this speed, Sy can be calculated as follows: Heat is lost from the tire through its sidewalls and circumferential surface to the surrounding air.


Home by dr. jose rizal essay

Global organizations use these htesis to create value. The map indicates significant points of interaction between the trucks. Chapter 9 shows the economic results of these comparisons to quantify the potential improvement in monetary terms of an AHS system over a manual truck fleet.

UBC Theses and Dissertations. The driver took 24 seconds to complete the segment.

juliana parreira thesis

Original tread wear data as a function parreeira temperature and speed as reported by thesi Miller Rubber Company Popular Mechanics, The distribution shape of Lucy mine data is assumed as normal and from this information; the model reproduces a normal distribution for the all drivers speed. Employment is an important contribution that a mining company creates for a community, and this forms an important part of the corporate-community relationship, reputation, and social license to operate.

Home by dr. jose rizal essay

This type of failure can be catastrophic if a high tire temperature exists at the time and may result in a blown tire or an explosion. Heat enters the tire through the contact surface with the road and from the flexing of the tire sidewalls as the tire rotates.

juliana parreira thesis

The time to decline from this value back down to ambient conditions jjliana a bit longer at about 90 minutes. As such, at this time, automation is not a universal solution for all challenges faced by underground mining. Only a portion of the Lucy mine haulage system is modeled in this work with two shovels digging ore and waste to achieve a stripping ratio of 0. In rhesis to account for loading, unloading, and productivity in the model, data from the Lucy mine was obtained from the VIMS?


The conventional TKPH calculations tell the user very little and serve merely as an alarm Joseph, In addition, the model counts and stores the number of interactions that each truck has encountered. A second factor to be considered is the influence of tire diameter. Average haulage distances for several trucks at the Lucy mine VIM data.

juliana parreira thesis

For the Miller data, the tire diameter is estimated at 0. This contact percentage is 7. At the start-up and shut-down of each shift, significant fuel use results as the trucks idle during the change-over of drivers as well as the need to drive to and from the point of shift change-over. Each mine has unique variables such as weather, road material type, etc. The data is held in an internal ExtendSim database stored with the model to open, 22 save, or close when the model opens, is saved, or is closed respectively.

Juliana parreira thesis

The model uses fuzzy logic to determine this factor as described in Section 5. If a greater time step value is selected, trucks may not be where the system believes them to be at each step.

Although AHS trucks drive slower than normal drivers, htesis cycle time is shorter than manual because manual breaks involve assembling at the parteira lot for safety purposes. Tire Construction and Nomenclature By knowing the instantaneous speed of each time step, the model uses one of these equations to determine available Rimpull Figure College application essay sample harvard.