I have been a proponent of the concept that coins do not sink under natural circumstances for many years. This is a hotly debated topic with many metal detector gurus. Soil stability becomes a key factor that is easily overlooked or not addressed by many.We will examine the sinking possibilities in relation to this factor. However, let me tell you why I have not been a believer in the coin sinking theory for nearly 40 years.
I started metal detecting on Christmas day of 1969 with a BFO detector manufactured by a Florida high school science teacher. I was hooked on the hobby the very first day. Good finds were everywhere and in large numbers. Over a 40 year period I have dug-up more than 153,000 coins with more than 15,000 being silver. I have searched and hunted very heavily in my favorite city, Tarpon Springs, FL. 135,000 of my total coin finds have come within a five mile radius of this community from the land as well as the Gulf of Mexico. Florida soil is, for the most part, very sandy. I have dug up coins from the very surface to nearly seventeen inches deep. Some of my most valuable finds have been large coins like US half and silver dollars. Most of them have been less than two inches deep. My deepest large coin find was a 1921 silver dollar in a coin bezel at 10 inches deep. Did it sink to 10 inches? Absolutely not! I found it on a school yard that dates to the late forties and has had two sod replacements / layovers in a 50 year time frame. The same day that I found it, I dug 36 Mercury dimes in a four hour period. This was the day of replacing the sod and about six inches of sod and dirt were removed making the dollar and many dimes reachable with my Fisher 1260. Most of the deep buried new coins can also be explained by the actions of man upon the environment. I could write a book on the valuable coins that I have recovered at shallow depths that were dug from land that no one had altered or had previously been worked by other hobbyist with metal detectors. There are circumstances that are not easily explained that I call soil stability issues.
If you are hunting in areas where new coins are being found at eight inches or deeper, I would surmise that there could be a soil stability failure or the possibility that man has altered the environment dramatically. Historically, there are cities and unbelievable treasures that that are buried deeply that will never be recovered that are the result of soil stability failure. Even with the most powerful and advanced metal detection technology, these sites are not within reach. There are two methods of determining the soil conditions and both are useful to the hobbyist in finding success in metal detecting.
The first method for soil analysis is visual. In areas where there is no soil and exposed rock, granite or coral are prominent, it is obvious that coins could not sink. In areas that have thick carpet grass and lots of rainfall there will be heavy grass clippings that will cause coins and other valuables to appear to sink. This is not a very stable soil area. Find areas where the grass is having trouble growing, or has bald spots where there is no grass, and you probably have fairly stable soil. This visual analysis can help determine whether a spot is worth hunting. However, the second method, electronic analysis, is the easiest and is done with your metal detector.
Using your detector, take a sample of the deer targets, to determine the age or era of those finds. If the defect items are relatively new, there is a high probability of the area being covered with fill dirt or was bulldozed. Move to another area and check again. If, the targets at greater depths are consistently older, then you are hunting in a stable soil area that is conducive to finding valuables. Always remember that soil conditions can change dramatically in a short distance. Another technique to aid in checking out a potential site is to check out the trash targets. Trash, including iron nails, will help identify the era of a property. Check out all the non-ferrous items like foil, pop tops, coins, etc. Pop tops and pull tabs came along in the early sixties and areas without them are typically older. Remember, that all pull tabs, foil, gold rings / coins and other gold jewelry, will 90% of the time, read foil or pull tab on the modern metal detectors.
There are areas that I believe that true sink rate can be found. Soggy bogs, murky grassy shorelines, heavy surf areas and woodlands have natural conditions that would cause dropped items to sink or disappear quicklyly. These areas for the most part are not conducive to metal detection success and should be avoided. The real keys to metal detecting success are good equipment and the intelligence, awareness and savvy of the operator. Mindset really matters! Become a treasure finder-you can do it!