To provide an accurate response regarding the primary cause of pollution in Mine Gap Run, I would typically conduct a search for relevant information. However, I can share general insights based on common pollution sources that might affect streams and waterways like Mine Gap Run.

Pollution in streams and waterways often stems from several key sources:

1. Agricultural Runoff: Fertilizers, pesticides, and herbicides from nearby agricultural activities can wash into streams during rain events, leading to nutrient pollution and harmful algal blooms.

2. Urban Runoff: In urban areas, rainwater can pick up pollutants such as oil, heavy metals, and debris from roads and buildings, which then flow into nearby water bodies.

3. Industrial Discharges: Factories and industrial operations may discharge pollutants directly into waterways if not properly regulated.

4. Wastewater Treatment Plants: Sometimes, effluent from wastewater treatment plants can contribute to pollution if the treatment processes are inadequate.

5. Sedimentation: Erosion from construction sites, deforested areas, or agricultural land can lead to increased sediment in streams, which can harm aquatic habitats.

For the most accurate and specific information regarding Mine Gap Run, including any local studies or reports detailing the causes of pollution in that area, I recommend checking local environmental agency reports or studies conducted by universities or environmental organizations.

If you have access to specific data or reports regarding Mine Gap Run, please share, and I can help interpret that information further!