Guide to Surface Prospecting — Nicholaus Vieira

In order to survey a cave you must first find them. This involves surface field work that can involve examining satellite imagery, aerial photography, topographical and/or geological maps, then systematic surface examination of the terrain... or, going for a hike and asking locals.

Acquiring Topographical and Geological maps in Lima, Peru for areas of exploration interest.

All of the data which is collected should be saved and organised to better help analysis future exploration and studies. Databases and Geographical Information Systems are a good way to do this. It is possible to overlay various types of maps, GPS way-points, GPS track-logs, cave line plots, etc to better direct surface search efforts.

QGIS is a free GIS program which is gaining in popularity among cavers. Here is the link.

Below is a basic guide of what information to collect when Surface Prospecting. A list of equipment needed to prospect for caves will be in a separate post.

Searching
1.   Divide the area to be inspected into smaller zones. Use the terrain features to help set the boundaries of each zone. Designate each zone with a letter. (18AA05= Year 2018, Zone AA, Cave 05)
2.   Using a GPS device (dedicated unit, or phone with an appropriate application) begin a track log of the path which you travel.
3.   Systematically walk each zone, start high and work to low. Use the contour of the slope to your advantage. Remember to look back every now and again.
4.   If you are unable to get into an entrance (climb, pit etc), describe what equipment would be needed to gain access on the entrance sheet.

Searching for potiential entrances (Peru)

Entrance photos
1. Take a location (far-away) and entrance (close-up) photo for each cave you find. A person or rucksack for scale is always a good idea.
2. Record the photographer, and frame number along with the cave's GPS data on an Entrance Sheet (to be entered into the projects GIS when back at basecamp).

Standing next to the large entrance of Coincidence Cave for scale (New Zealand).

Names
1.   Always ask locals to write down the name of any cave or locality.
2.   Note the source and reliability of the name, ie. local/non-local, literate/semi-literate.
3.   Use the Projects Naming protocol to give the feature (Cave, Sink, Spring, etc) a numerical name (18BB05).

GPSing entrances and features
1.   Set your gps to UTM WGS84 meters.
2.   Aim for an epe <10m. In a pinch, anything is better than no fix, but readings worse than 20m are highly suspect. Attempt to use waypoint averaging if possible.
3.   Vertical error is ~5 time that of horizontal error. If your gps shows 3 or fewer satellites, it cannot give an altitude fix for the entrance. If necessary take a second reading from a different position level with the entrance in order to fix the entrance elevation, or use an altimeter if available.
4.   Mark the GPS point at the entrance with red paint (nail polish) or a half-drilled hole so underground surveys can be tied into it. If you can't get a fix at the entrance, surface survey to it. If a surface survey is not possible, estimate the distance, bearing and height difference. This is very important for making a map of all the caves of the area. While Cairns, and flagging are options more permanent solutions should be used when possible.
5.   Record the zone, northing, easting, altitude, position error, gps owner, gps model, waypoint name, and position of the reading relative to the entrance on an Entrance Sheet.

Marking a potientail cave entrance in Peru.

Entering the cave
1.   Get together with a partner. At least 2 people check out the cave together
2.   After checking out an entrance, write a short description of the cave and a sketch.
3.   Mark the cave number inside the entrance (use brush to clean rock before marking). Keep the number discrete but noticeable, so it could be found again (a few years later).
4.   Go light, Have fun.

Descending a 105m surface shaft to see if it continues into the unknown (Peru).

End of recce
1.   Record the day’s events in your logbook, and in the projects diary.
2.   Give all data to the Project leader for organizing the next phase of exploration. Make sure to upload the GPS track log, GPS way-points, and photos to the expedition computer.
3.   Write an article for a caving magazine.