Minex Tips – Pit Design, How to Create a Switchback Ramp

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When Mining Engineers want to create a ramp for a pit design, whether along the pit boundary or along intermediate strips, the ramp parameters they need to consider for the design include ramp gradient, ramp width, ramp and berm intersection criteria and switch back details, amongst others. GEOVIA Minex provides the features and tools required to create ramps both along pit boundaries or along strips. The following process details how to create a Swtichback Ramp.

To build a pit with ramps you will need to have a GM3 file open, a bench list file ready. You can create a Pit design boundary for one starting bench for crest or toe using the pit/dump design menu and digitise the boundary.

Normally you would move the digitised boundary points and create a place where the ramp would start. Note the two encircled points in the images below. The selected line is the base line or the boundary that you have digitised first. This could be the pit bottom or the pit crest line.

 

 

 

Choose, Normal Manual option in the pit/dump design menu for creating the rest of the pit boundary. In the Pit Design form you will be required to define the Ramp as below:

 

 

Select Build Ramps, then you have to define the ramp using the Create/Edit Ramps option. Fill in the details in the Edit Ramps form as below.

 

 

There are 4 types of Berm exit, choose the one that suits you best to design the berm and ramp intersections. Taper distance is the distance over which the ramp width would increase from just the defined ramp width to ramp width plus berm width, as shown below.

 

 

Once the details are filled in, click on “Fill Table”. Note the Lower Bench and Upper Bench option here. You could have a ramp from a certain bench to another. You could then decide to change the direction , width or other parameters of the ramp and go for the next few benches. In order to create a switchback you would alter the direction (Type) of the ramp from clockwise to Anti Clockwise or vice versa.

Once you click OK on the Pit/Dump design menu you will be prompted to choose the two ramp start points. Choose the two circled points as shown earlier. Note that there should be no intermediate points between the two points to be selected as ramp starting point. As you keep progressing the pit the ramp will also keep progressing between the upper and lower benches selected earlier. You might sometimes be prompted to select Ramp points. Ramp points are sometimes lost and you may have to choose the points again.

For creating a switchback the process remains the same, only that you may like to move the points and create some room for a switchback as in the image below. Before you go for a switchback click on the Reset ramp points.

Move the points of the toe in such a way to make room for trucks to turn and for the next ramp to start. When you click OK on the Pit/Dump Design window you will be required to select the new ramp points again.

You will be prompted whether you want to delete the existing ramp, choose No. Also you would be prompted on would you like to combine it with the previous ramp, choose yes.

 

 

You can be creative with your ramp and switchback designs and create the ramps to suit your site requirements.

 

 

The above process can be repeated for Strip Ramps as well, if you wanted to do some intermediate phase ramps for your pits.

 

 

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Ranajit Das

Ranajit Das

Senior Mining Industry Process Consultant, GEOVIA at Dassault Systèmes
Ranajit is a qualified Mining Engineer with over 22 years of experience in mine planning, consulting, operations, logistics, exploration and feasibility studies. Ranajit has previously worked for the Steel Authority of India, Santa Fe Mining in Chile and JSW Steel in India. He specializes in GEOVIA Minex and Surpac.