A Baseline Lunar Mine by Richard E. Gertsch

In this section I propose a modest lunar mining method. It illustrates the problems to be expected in lunar mining and how they might be solved. While the method is quite feasible, it is, more importantly, a useful baseline system against which to test other, possibly better, methods. Our study group proposed the slusher to stimulate discussion of how a lunar mining operation might be successfully accomplished. Critics of the slusher system are invited to propose better methods. The group noted that while nonterrestrial mining has been a vital part of past space manufacturing proposals, no one has proposed a lunar mining system in any real detail (Carrier 1979, Williams et al. 1979). The group considered it essential that the design of actual. workable, and specific lunar mining methods begin immediately.

Based on an earlier proposal (Gertsch 1983), the method is a three-drum slusher, also known as a cable-operated drag scraper (Ingersoll-Rand Company 1939, Church 1981). Its terrestrial application is quite limited, as it is relatively inefficient and inflexible.

The method usually finds use in underwater mining from the shore and in moving small amounts of ore underground. It uses the same material-moving principles as more efficient, high-volume drag lines.

The slusher is proposed here because the LOX-to-LEO project is a very small operation by terrestrial standards and requires a method that minimizes risk. The three- drum slusher has already proven itself in this context. It has the advantages of simplicity, ruggedness, and a very low mass to be delivered to the Moon. When lunar mining scales up, the lunarized slusher will be replaced by more efficient, high-volume methods, as has already happened here on Earth.

The Machine and Duty Cycle

Before discussing the advantages of the machine in a small-scale startup lunar mining scenario, I will describe the slusher and its duty cycle. It consists of the following modules (see figs.18 and 19):

1. A mobile power unit and loading station-including three drums around which the cables are wound, a mechanism to place anchors, a mechanism to change tools, an optional operator cab, a dozer blade, and a conveyor to load material into the electrostatic separator
2. Three lengths of cable to operate the scraper or other mining tools
3. Two anchored pulleys
4. Interchangeable working tools, including scrapers, rakes, plows, and rippers

Figure 18

The Mobile Lunar Slusher
Several features of a mobile slusher (cable-operated drag scraper) are shown in this perspective view. The scraper loading material in the center of the pit will continue to load material until it reaches the discharge point or loading station to the left. In the method proposed in the text, the slusher will load into a mobile mill module with the aid of a conveyor.
(Neither the conveyor nor the mill module is shown here. The module behind the loading station is a transporter.) The mobile power unit/loading station will be anchored (not shown) to counter the forces on it. The function of the two anchored pulleys should be clear from the illustration. The" box-type" slusher bucket has enclosed sides, which keep the very fine lunar material from spilling out while being loaded and transported.

Figure 19

Side View of the Mobile Lunar Slusher
This side drawing of the slusher shows the mobile mill module behind the combination power unit and loading station. In this setup, the material from the slusher bucket is dumped directly into the mill module. The pylons holding the pulleys must be firmly anchored. They position the bucket when it is pulled out from the loading station into the mining area.

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