Hola G.M. I'm not a native speaker of English, but for what I see, there's an error in your first sentence. This is what I understood: 1. Soil and rocks FROM EXCAVATIONS ARE left in huge tips. Then, in this case, the translation would be: 1. El suelo y las rocas de las excavaciones se dejan en enormes vertederos. Talking about your second question, "Washing" has to be translated as "Lavar", not "lavando". This is a common problem for ESL students, because we tend to translate the sulfix "ING" as "NDO", like in "washing > lavando", but it's not always like this. When you're talking about an action, you refer to this action using a Gerund form of the action (verb). For example: Swimming: Natación. Not "nadando". Ex.: Swimming is good for health. Cooking: Cocina. Not "cocinando". Ex.: Cooking is like a therapy for me. Listening: Escucha. Not "escuchando". Ex.: You need to improve your listening. You might want to study a little more of Gerunds and Infinitives. It will help you a lot in your reading comprehension. Well, that being said, in this case, "that" is not necessary. The translation would be: 2. Lavar el suelo para aislar minerales contamina los ríos y arroyos. Just remember, I'm not a native speaker of English or Spanish. So it might be innacurate. But I hope this helps you, amigo. =]

I see THAT SuKi and Vitor have pointed out THAT THAT 'THAT' THAT you think is a missing 'THAT' ' is actually a 'THAT' THAT you don't need.

1. I'm guessing that this should be: Soil and rocks from excavations is left in huge tips. A 'tip' can mean a pile of refuse, as in, for example, 'a rubbish tip'. So it's the opposite of a hole, in fact - it's a large mountain of unwanted soil and rocks, discarded after the excavations. 2. Washing the soil to isolate minerals pollutes rivers and streams. There is nothing missing from this sentence. I think you are reading it wrong if you think that there should be a 'that' in it. Try looking at it like this. [Washing the soil to isolate minerals] [pollutes] [ rivers and streams] 'Washing the soil to isolate minerals' is the subject, 'pollutes' is the verb, 'rivers and streams' is the object. There's nothing missing.

Yes, I think a tip is the bottom of the holw for a foundation or piling. I think the second sentence is saying rivers and streams are polluted when soil is washed. That is, the water returned to the stream after washing soil is muddy or cloudy and that harms the stream.