If the item was dug from the ground

[keannu]

After I came to know there's also conditional 0 which is about factual things that actually happen, the barrier between factual conditionals and predictive conditionals became vauge for me. Is the underlined factual conditional(conditional 0) or predictive conditional(conditional 1)? It seems to be something that happens regularly to him, so it can be labelled as a factual conditional, but if it's something whose factuality he doesn't know, then it's conditonal 1.
Sorry, labelling may not be important, but I'd like to know the distinction between the two conditionals.

ex)Almost every year a person arrives at my office with artifacts he or she has found outdoors - stone arroheads, bits of pottery, and so on - and wants to know what these pieces represent, how old they are, and who used them in the ancient world. My first question is always to ask where the artifacts came from, but unfortunately the answer is normally too vague. Knowing which layer under the ground an item came from is vitally important because layers stack up over time. That's because a few centimeters may mean a difference of thousands of years. If the item was dug from the ground without carefully recording the various layers, I have no way of knowing whether it came from layers 10,000 years old or 1,000 years old.....

[5jj]

I vaguely recall telling you in one of your numerous threads on this topic that, if you wished to compartmentalise conditional sentences, there were more than fifty types. It seems that you are still trying to slot all conditional sentences into one of three, four or five types.

Good luck.