New Zealand Gold Prospecting & Metal Detecting Forums Archive

well i know myself and rgmcbrid went to some of the beaches here in CHCH and found coins anywhere from 3 to 6 inches deep...but havnt done alot of beach detecting yet so not real experianced with it..just wanted to give the depth of the coins i found.

The coins will slowly sink in the sand even if undisturbed because of gravity until they come up to a layer of the same or more density. Then they will stay there until disturbed. Thus above the high tide mark they could slowly sink a matter of metres until they come across hard packed shell or sand or bedrock etc.

Storms will come in cut away the sand and wash them out then redistribute them around. Because this things of similar weight will end up accumulating in the same area thus the term "Coin Lines" etc that are used. And its the reason that if there are a lot of sinkers in a area the chance of gold is very high.

My best beach finds have been when the sand has eroded away by either wave action or rain wash out down to the bed rock / clay. At these times the area is literally carpeted with coins and the detector is going off constantly.

I'm down to St Kilda St Clair beaches, Dunedin today low tide 5.24pm. Massive undercutting along the two beaches. Its usually the best time for me when beaches have undercutting. I'll let you know how I get on.{ Using my minelab sovereign GT}

For most of the overseas vids I have seen they are hunting recent drops. Modern coins and jewellery that were dropped that day or the day before. The encrusted jewellery and old coins that are sometimes shown are found either after a storm has shuffled things around or in areas that have eroded away.

I find it hard to spot erosion on an ocean beach unless it is obvious like a cut etc. By just glancing at a beach it is very hard to say if the sand has built up or eroded away unless there is something like a rock outcrop or wooden pile to compare the level with.

But there are other clues:

1. Seaweed and loose shell - means the sand is building up

2. Small pebbles and rocks - dig under them, chances are there is plain sand underneath. This means build up.

3. Flat spots of firm sand that look wet - if the sand is firm it is a good sign that the loose layer of sand has been removed and the wet look is from a thin layer of water that has accumulated in a low spot.

4. Larger 10" etc sized rocks sitting around in firm sand - eroded area with good chance of gold and heavy items.

5. Dark brown "old" looking shells - eroded area but will most likely only hold lighter treasures.

6. Ripples in gutters running along the beach near the low tide mark - forget it, although lower then surrounding area I have yet to find a target in these.

7. Gutters running along where the steep high to mid tide area meets the low tide area on an angle. Worth while, normally some targets especially coins here and a few feet on each side of the gutter. If the sand is soft its not so good but still worthwhile. If it is firm it should hunt very well.

8. And of course any cuts from wave or rain washout, exposed rocky platforms that don't normally show (especially in the dry sand area) and wash outs of the dunes or banks.

The above are just my observations since I started at Xmas, but I'm finding them running true. Lately I have been amazed how the gutters in N.o. 7 have been formed on our local beaches when there is almost zero wave height. The main thing to look for is any difference in the beach from the previous day and for firm sand. Loose fluffy sand especially in the wet seems to be a waste of time.

Also if you are digging pull tabs or can slaw in the wet sand - move on and don't even look further in that area.

Hope this helps.

oh yea just did an air test on my detector and seems to have a 4-5 inch max scan depth so this could be less in sand .
With this in mind it is probably a little weak for deeper beach targets will have to wait for a storm and stick to grass.
Thanks for your responses......

Nice to hear from another Dunedin metal detectorist. You have done well. I worked right in the water line today and had heaps of strikes just in front and to the left of the st kilda club house. I was hoping for a ring and expected one with so many strikes. here is my post rock tumbling shot with the coins cleaned up. I keep the old currency and bag them up for dropping off to the reseve bank in wtgn on the way through to ak at xmas time. The pre decimal I keep. I know what you are saying about the right of the club house side just along a bit towards middle beach but not as far. I found lots of predecimal last winter there and the earliest coin last winter was a 1860s chch shop token.

Rusting silver coins? Don't quote me on this, but I think our current 'silver' NZ coins are silver in appearance only. From memory they're actually nickel plated steel.

I bought a Lortone model 3A tumber at a large rock tumbler type shop in Rotorua. I believe it was the only shop in NZ that specialized in these. It is a USA made tumbler.

I tumble most of my finds. I don't use commercial grits, though I do have them, but rather sand and stones, and dish washing liquid. I tumble for an hour then wash it all out through a sieve, into an icecream container. Then I take out the cleaned coins and put the rest back in with fresh water and new dishwashing liquid. I can repeat this several times. I clean the old currency just enough to look semi respectable for bagging up to sell back to the govt. The modern coins I clean until they are usable.

The reason why I got the tumbler was that it was embarrassing taking modern currency that has been in the ground or sea and trying to spend it and have retailers or supermarkets look at it closely and sometimes rejecting them. Some banks were good others not so good. And I didn't like having to explain to anyone where the coins came from.

Parks are good too. Thats why I bought an LCD metre for my sovereign so I could set it to +20 and dig up only $2 or $1 coins.

went out today for the afternoon...found 25 coins in total..i had discrimanate set to around the 64 mark to get rid of some of the junk...
i may have missed some different things but until i get use to all the signals i put it on one that i know prety good..lol

and after giving them a clean i have discover that my oldest coin found to date is an 1888 penny found today..along with 2 half penny's 1933 and 1952..my first half penny's ever.

Edited by user Friday, 26 August 2011 8:58:56 PM(UTC)  | Reason: Not specified

very cool..you say you thurpence are between 1934 and 1940...any 1935?