You often hear about people saying to dig the “Black Sand” to find gold.
Here’s a hole I threw down on a nearby beach which demonstrates why people get excited about the black sand.
This hole is around 40cm deep and shows the light, fluffy highly mobile blonde sand on top, about 10cm of it.
The lighter sand (predominantly ground up shell) comes and goes readily, and moves with every tide, and even by wind and rain. This stuff is your enemy unless you are collecting yesterdays drops or pulltabs.
Further down, you can see how the sand is starting to become graded as the heavier black sand (rich in iron, manganese and other minerals) migrates downwards, by gravity and micro-vibrations from every single wave hitting the beach…
Finally, at the bottom of the hole, you can see dense black sand sitting hard on the clay bedding on which the beach has built up on. This is what you want to see and where all things will eventually go to hide.
I’ve had a few golds out of this particular clay,a couple were actually recessed into it where they’ve sunk into the clay over time.
Get to know your beach. Pick one or two beaches that you can visit easily.
Visit them at least once a week, take photos of rocks and note which weather / tide conditions expose them, and which cover them. Look how sand moves around headlands, how it builds in one spot and erodes in another.
Dig some test holes to see how deep the blonde sand is. Check each end of the beach as well as the middle - and if you hit rock or clay just under the surface nip back to the car and grab the detector!
Make a mental note of the gradient of the beach - if the gradient lessens, then hunt the top of the beach as it’s a good chance sand has been pulled from the upper beach and deposited further down the beach. Equally, if it gets steeper focus on the low tide mark.
Banks of pebbles and shells can be worth a swing if you’re chasing coins as coins flip around in the waves in a similar fashion and end up tucked in with the larger shells. If you’re only pulling tabs though and foil etc, you’re too high.
Finally - don’t hesitate!
I was swinging before work one morning and found a gutter - Was pulling a ring or a $1/$2 almost every other step!! But being a good lad, I went into work. Back that afternoon (and only one tide) and the gutter was gone. Buried under I have no idea how much sand…Never seen it since (and it’s a regular beach for me). So I watch, and wait…Kicking myself.
Next time, I phone in sick - or at least turn up late!
Awesome tips man ive been watching ninety mile for a few months…went out last week and tide was the lowest i seen it in the year i been here…
I was only going for a dive and didint have my detector…
They aren’t big tides at the moment (Low tide there is currently 1.2m higher than the lowest low), so if the water goes out a long way - it means there’s a helluva lot of sand (effectively pushing the low tide mark further out)
What you want is the big tides, and the water not going out a long way at low - this means there’s less sand on the beach (allowing the water to come in closer) If that makes sense?
What you’re looking for there is a week of big southerly swells to wrap around Tauroa and cut the sand out.
Big tides this month are 17th and 18th (LT will be over a metre lower than it is today at Te Kohanga)
For now, check where all the surfers park up - will be tons of caps and tabs, but I’m picking a few silver rings or bracelets (which will be well clear of the aluminium range) - Not too many surfers wear gold. And should be enough goldies to help pay off the detector.
Don’t leave the detector in the car, especially in summer - the heat will kill it (if someone doesn’t nick it).
awesome tips and pointers…ill start watching the swell and wind conditions aswell now…found my first ring in a million pull tabs and bottle caps.was only rubbish but just gives me more incentive to get out there more im going for a look out taipa this weekend still learning and gratefull for all the tips and pointers
Tip#2 Predominant Littoral Current (Longshore drift)
Look to see which way any sandspits are pointing…
In the picture above, the sand will usually (usually) be deeper on the right hand end of this beach (it’s also where all the ali tends to end up).
However, the other end, whilst losing sand to this bit, is also being replenished from elsewhere - you need to work out what sea conditions interrupt the replenishment, which is when a beach starts getting eroded before rebuilding once the sand ‘conveyor’ gets going again. This could be as little as a few hours with a particular swell or wind direction.
I often throw a chunk of driftwood into the surf to see which side it goes - then head the other way.
