Data type error in Excel Power Query

You forgot to attach sample files. If you attach it then please put the PowerQuery into it.
My hints:

1. Are you sure that the error is caused by that table and that column?
2. You should check subsequent transformations maybe the error happens later.
3. You should check other tables as well (you mentioned that you appended many tables)

2020 Monthly Haul Sheet.xlsxMTR Report - NEW.xlsx

Sorry.  I was sure I had attached them.  
The reason I think it's that particular column in that table is because when I open the query for that table, it shows errors in the column, and it doesn't show it in the other tables.  The data is importing correctly from the other tables.  I don't know much about Power Query, just enough to be dangerous.

What column is the problem in?

Looks like the query is not finding the source file for June and August.  If you changed the file name or location from the last time the query was run it will error.  Either need to save erroneous file in same location and with same name as previous file, or change the location to the new file.

Oops..  My mistake I don't imagine you are getting that error.

Okay, let me start over. So the 34 tables are all brought into Power Query editor as separate queries, right?  

If I look at the M code for the months that the query worked (April, May, July) have one more line of code than does August.  I am thinking this may be the problem.  Now, the solution may be to simply copy that line of code and add it to the August query and refresh and see if this works.  This is assuming the data fields are the same every month.  Do you want to give this a try?  

Which query in NEW is the problem?  Aug_2020?

Okay, I have attached three months of Power Query code for June, July and August for you to see.  My guess is there is a problem with data type in your queries.  If you look at #"Changed Type"  & #"Changed Type1" for each of the months you will see inconsistencies.  This could lead to data type errors when trying to append these queries together.

My guess is the original queries for each of these months (#"Changed Type") attempts to determine the data type upon load of the source data.  But because sometimes data coming in differently from source the query can make different decisions for a field's data type.  This is the first problem.

Then someone is trying to change the original data types with #"Changed Type1", but may not be covering all the differences. Part of the solution should be (for all queries) to delete the data type step #"Changed Type", and make all the changes to your data types one time manually.  Then those changes should be replicated in all the queries.

EE Power Query.docx

I'm sorry for the slow reply.  The error is in the Load Type column.

So, if I understand, I need to remove all of the Changed Type steps from all queries, and then only change it in the appended one?

I consolidated four months from your data.  See how it looks..EE-PowerQueryTest.xlsx

It's still not showing the load type for August.  I am going to try creating a new test file like you suggested and see if I can get it to work.  I will not be able to respond for a few days.  I will be on vacation, away from technology, until Wednesday.

No problem.  Are these monthly tables going to be in the same workbook?  Separate workbooks?

They are all going to go into one workbook.  I am summarizing all of the data and comparing by year and month.

I took your advice and started from scratch.  I created queries for each of the source tables, deleted the bottom row (Totals) from each sheet, appended them, and then changed the data type for each column.  The errors are gone.  Thank you for your help.  I think I just over complicated something that should have been simple.