The goals of this lab were to learn how to do raster analysis, build a sand mining suitability model, build a sand mining risk model, and overlay the results of these two models to find the best locations for sand mining with minimal environmental and community impact.
Suitability for mining:
1. Generate a spatial data layer to meet geologic criteria
2. Generate a spatial data layer to meet land use land cover criteria
3. Generate a spatial data layer to meet distance to railroads criteria
4. Generate a spatial data layer to meet the slope criteria
5. Generate a spatial data layer to meet the water-table depth criteria
6. Combine the five criteria into a suitability index model
7. Exclude the non-suitable land cover types
Risk for mining:
1. Generate a spatial data layer to measure impact to streams
2. Generate a spatial data layer to measure impact to prime farmland
3. Generate a spatial data layer to measure impact to residential or populated areas
4. Generate a spatial data layer to measure impact to schools
5. Generate a spatial data layer to measure impact on local parks
6. Combine the factors into a risk model
7. Examine the results in proximity to prime recreational areas
Datasets and Sources:
Bureau of Transportation Statistics: Rail terminals feature class.
Wisconsin Geological and Natural History Survey: Bedrock Geology of Wisconsin, West-Central Sheet.
Methods:
For the suitability model, variables followed a similar workflow. The geology feature had to be converted into a raster before it could be reclassified. The Euclidean Distance tool was applied to the rail terminals feature in order to create rings around them to represent distances from any given point on the map. Then it was reclassified. Slope was calculated for the DEM and then Block Statistics were applied in order to create an average to smooth out the results. Then the slope was able to be reclassified. Land Cover, and Water Table Depth were able to be reclassified right away. The categories and reasoning behind the reclassifications will be discussed below. The final step in creating the suitability model was to use the Raster Calculator to add up all of the rasters.
| Figure 1: Model used to create the Mining Suitability raster. All of the reclassified rasters were added together to produce this. |
Normally, all of these processes can be done using model builder. For some reason, there were issues with model builder while working on this project that limited the tasks it could be used for. Everything was reclassified before putting it into model builder in order to deliver exactly what was needed for this portion of the lab.
| Figure 2: Reclassification of Geology features. These two were isolated because they are the only ones that are viable for sand mining. |
| Figure 4: This table shows the reclassification of the distances to railroad depots in miles. This was determined on an exponential scale while thinking about convenience factors. |
| Figure 5: This table shows the slope of the land cover in terms of percentage. The lower percentages are much more suitable than the higher percentages. |
The next portion of this lab examined the criteria for sand mining impacts on the community and environment. This involved looking at rivers, farmland, residential areas, schools, and parks. For each of the criteria, they were broken into 3 ranks (3= high risk, 2= moderate risk, 1= low risk). Euclidean distances were calculated for all these features because distance is a main factor in the impact mines have on them.
| Figure 7: This is the model used to calculate the Risk Index. Similar to above, all of the reclassified rasters were added together to produce this. |
| Figure 11: This shows the risk factor near schools. The closer the mines are to schools, the more dangerous they become for the kids. |
| Figure 12: This shows the risk factor near parks. People will not want to use parks as much if there is a ton of pollution from these sand mines, so it is important to avoid them whenever possible. |
Results:
![]() |
Figure 13: Suitability Index map. This map shows where the land resources are most suitable for mining use.
The following maps were all added together to create this index:
|
Figure 16: This is the model used to execute the Viewshed tool.
|
Figure 18: This is the model used to create the final map. The two reclassified rasters were added together in Raster Calculator.
|
Knowing these results are important because sand mining is a growing industry in Wisconsin. It is important to keep in mind all of these factors when deciding where to put a new mine because there are a lot of implications associated with them. If done right, sand mining can be beneficial. If done wrong, more problems will be created than are necessary, and the entire industry will get a much worse reputation. These results can be very helpful to companies looking for places to start new mines, however these processes would be much more effective if experts in multiple fields were collaborating to create the most well informed classifications. The classifications for this assignment were done with best judgment in mind, but there is always a chance of error.
Conclusions:
Throughout this lab, it became very evident how complex the issue of sand mining really is. It is extremely difficult to be able to keep everything in mind, especially when it may not impact somebody directly. Overall, it is important that as many factors be considered as possible when working with sensitive topics, such as this one. If everyone works together, there will be a way to solve these problems. Using GIS to help compile these aspects into one place is just one of many useful ways of handling these types of issues.


















