Type 2 or 3 conditional

I’m learning conditional sentences recently ,and I’m confused by the two sentences below because they don’t seem to fit any type of conditional sentences my grammar book categorizes.

I think they look like mixed conditionals of type 2 and 3, but I’m not sure.

According to the book, the the main clause of type 2 is accompanied by common modals such as will, can, may, might, should; And the main clause of type 3 is accompanied by the modals would or could.

I’m not sure if I can use would in type two. If I can, what would be the the difference between using will and using would(I don’t even know whether this sentence is correct anymore😨).

Here are two sentences extracted from The Economist. Could you tell me which categories do they belong?

But it would be a surprise if the presidential election scheduled to take place in Venezuela is allowed to threaten the position of the country’s dictator, Nicolás Maduro.

That would be make it seem like a type 3, but that is allowed to seems like a type 2.

Finding a viable way to mine outer space’s plentiful supplies of platinum, for example, would surely lead to a meteoric descent in the price of the metal.

Is this even a conditional sentence? The book says nothing of this kind. Why did the author use would instead of will here? That would makes it sound like a past tense.

Thank you!

———————————————————— Skip this if you already know what conditional sentences are.

Here’s what the Top 20 grammar book says about the four types of conditional sentences.

Your first example:

But it would be a surprise if the presidential election scheduled to take place in Venezuela is allowed to threaten the position of the country’s dictator, Nicolás Maduro.

You are right to assume this is a type 3 conditional, according to the classifications in your book. If the Economist writers were following the strict rules that your book proposes, then the proper way to write this sentence would be:

But it would be a surprise if the presidential election scheduled to take place in Venezuela were allowed to threaten the position of the country’s dictator, Nicolás Maduro.

I would have written it that way, although as your text pointed out, many English speakers would have written was. Still, I don't think most speakers would combine "would" with "is." I'd say it's a grammatical error. Either "will" with "is" (which would make it a type 2) or "would" with "were" (which would make it a type 3) is much more correct here.

Your second example:

Finding a viable way to mine outer space’s plentiful supplies of platinum, for example, would surely lead to a meteoric descent in the price of the metal.

This is another form of the type 3 conditional, although your book doesn't seem to cover it. The first part isn't worded using an "if" statement, but a gerund phrase like this, followed by "would" is another proper way to describe something imaginary. It could be reworded like this without changing the meaning, at all:

If we found a viable way to mine outer space’s plentiful supplies of platinum, for example, it would surely lead to a meteoric descent in the price of the metal.

Note that you can also use infinitive constructions this way: "To find a viable way . . . would surely lead . . . "