Demonstration of Optical Microscopy and Image Processing to Classify Respirable Coal Mine Dust Particles

Round 1

Reviewer 1 Report

General comments:

This paper reports a novel method to classify coal and mineral in respirable coal mine dust based on an optical microscope and a classification model. Appreciable efforts were made to give us a comprehensive understanding of the performance of this method. The figures are presented properly, the manuscript is also well organized. Overall. I recommend this paper to be accepted after minor revision.

(1) Line 113-116, what is the collection size of this cyclone? (2) Figure 2, I am wondering if particles could uniformly deposit on the filter? Could the inlet influence the distribution of particles on the filter (i.e., more coarse particles deposit on the center and more fine particles on the edge)? This may affect the results between OM and SEM. (3) Line 303, “too” should be “to”.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

This is an interesting paper in which the authors aim to demonstrate the potential for optical microscopy with cell phone-based image analysis can distinguish/fractionate coal dust vs. mineral dust collected from coal mines. The focus is laboratory-based, and although the results are promising, additional pilot testing in real-world settings is indicated. This paper is outside my area of expertise; I do not have substantive comments on the methods, although they appear to be thoughtfully designed, executed, and well-written. 

pg. 10, line 308: "This performance is outstanding..." This seems inappropriate, especially for a Results section. Recommend scaling back the language and/or moving it to Discussion.

pg. 10, line 303: I believe "too yield" should be "to yield"  

pg. 12, first few lines of Discussion: Recommend using less loaded language here. Allow the data/results to speak for itself and focus energy on conveying key findings and discussing implications/next steps.

pg. 12, line 346: Consider including more discussion on further potential for scaling of this novel application of existing technology, including a need for piloting in real-world settings and what would be needed to eventually meet requirements for MSHA's strict "intrinsically safe" approval process.    

Author Response

Please see the attachment.

Author Response File: Author Response.pdf