Chest Collector is new item in Mr. Mine released at 4th June 2021. You can get Chest Collector at 100KM between 9th and 10th miner. It look like a pile of boxes and you just click on it to acquire the structure.
You can upgrade the storage and chance of Chest Collector from Craft Center up to level 10.
It works during offline progress and fills up while you AFK.
The chest collector doesn't store the type of chest it collects only the number of chests in it and it rolls the type when you collect them. So I think there's a chance your gold chest could be deleted, but also a chance all your basic chest rolls get a second chance to be a golden chest.
As for the update of 17/12/21 the chest collector now stores both types of chest, basic and gold.
You can collect chests from Collector by Shortcuts shift+click.
|Level||Chance (%)||Upgrade Cost|
|1||5||1 Building Material|
|2||10||10 Building Materials, 15K Red Diamond|
|3||15||20 Building Materials, 20K Blue Obsidian, 200 Polonium2|
|4||20||50 Building Materials, 5M Californium, 150 Polonium3|
|5||25||100 Building Materials, 5M Californium, 5k Oil|
|6||30||250 Building Materials, 1M Californium, 500 Polonium3|
|7||35||500 Building Materials, 10M Carbon, 10K Nitrogen1|
|8||40||750 Building Materials, 25M Promethium, 25 Fermium1|
|9||45||1000 Building Materials, 1M Neodymium, 10 Fermium2|
|10||50||1500 Building Materials, 1M Ytterbium, 5 Fermium3|
|1||10||1 Building Material|
|2||25||5 Building Materials, 15K Red Diamond|
|3||50||20 Building Materials, 20K Blue Obsidian, 200 Polonium2|
|4||75||80 Building Materials, 5M Californium, 150 Polonium3|
|5||100||125 Building Materials, 5M Californium, 5k Oil|
|6||120||200 Building Materials, 10M Californium, 75 Polonium3|
|7||140||300 Building Materials, 10M Carbon, 10K Nitrogen1|
|8||160||500 Building Materials, 50M Titanium, 500 Einsteinium1 , 50 Einsteinium2|
|9||180||750 Building Materials, 1M Neodymium, 100 Einsteinium3|
|10||200||1000 Building Materials, 1M Ytterbium, 200 Einsteinium3|
Both chance and storage tables were updated to 0.27